DRH-EM Education

A knee dislocation is a very serious injury which involves dislocation of the tibiofemoral joint and disruption of all the ligamentous structures. Posterior dislocations occur when with high velocity direct trauma to a flexed knee, such as a dashboard impact in a motor vehicle crash. The most serious consequence of knee dislocation is a popliteal artery injury. The popliteal artery runs in the popliteal fossa and its relative immobility makes it susceptible to disruption when dislocation occurs. A popliteal artery injury is a true emergency. When repair is delayed for more than 8 hours, the amputation rate is greater than 90%. Hard signs of vascular injury include absent pulses, limb ischemia (e.g. a cool, mottled foot), rapidly expanding hematoma, palpable thrill or audible bruit, or history of pulsatile bleeding (in the case of penetrating trauma or open injury). Though not considered a hard sign, paresthesias also raise concern for injury to popliteal structures. The workup-up for ruling out popliteal injury includes serial physical exams, ankle-brachial indices (ABI), CT angiography, conventional angiography, and duplex ultrasonography. Patients with vascular injury require emergent surgical repair.

Carpal tunnel syndrome is a median mononeuropathy and the most common mononeuropathy in the body. Classic symptoms include pain and paresthesias on the volar side of the first, second, and third fingers and radial half of the fourth finger with symptoms most notable at night. Fourth finger sensory dysfunction on the radial aspect of the finger only is very specific for the diagnosis of carpal tunnel syndrome. Extension and flexion at the wrist commonly exacerbate the condition and can aid in diagnosis. Using the Phalen test, by holding the wrists in maximum flexion for at least 1 minute, reproduction of the symptoms helps to point toward this diagnosis. A positive Tinel sign yields tingling after tapping on the wrist where the median nerve passes through the carpal tunnel between the carpal bones and the flexor retinaculum. Both of these tests have poor sensitivity, and if negative, do not effectively rule out the diagnosis. A more specific finding is divided sensation of the fourth finger, with dysfunction on the radial aspect only. Treatment for carpal tunnel syndrome includes a splint on the wrist and NSAIDs. Recurrent symptoms sometimes warrant steroid injections by a hand surgeon and possibly surgical decompression.

WHY THE OTHER ANSWERS ARE WRONG

Some patients have weakness in the muscles of the hand, a condition known as Guyon canal syndrome or handlebar palsy. It is an ulnar mononeuropathy rather than a median neuropathy as with carpal tunnel syndrome. In this rare syndrome, there is compression of the ulnar nerve at the wrist that causes weakness of the intrinsic muscles of the hand. What often happens is that the sensory function of the ulnar nerve is spared or involves only the palmar aspect of the fifth finger and half of the fourth. Carpal tunnel can cause weakness in the thenar eminence, but not the traditional intrinsic muscles of the hand.

Carpal tunnel syndrome is caused by compression of the medal nerve in the inflamed carpal tunnel between the flexor retinaculum and carpal bones, not at the medial epicondyle. Compression here causes cubital tunnel syndrome, and patients have numbness and tingling in the fifth and lateral fourth digits.

Carpal tunnel syndrome is the most common mononeuropathy in the body and involves the median nerve, not the ulnar nerve. The most common ulnar nerve mononeuropathy is cubital tunnel syndrome. Patients typically have paresthesias of the fifth and lateral fourth fingers. Ultimately, weakness of the intrinsic muscles can ensue.

The correct answer is inability to fully extend the knee. The remaining answer choices are all components of the Ottawa Knee Rules, which include: Age over 55 years old, isolated patella tenderness, tenderness at head of fibula, inability to flex knee 90 degrees, and inability to bear weight (4 steps) immediately after injury or in the ED.

Compartment syndrome is diagnosed by a compartment pressure greater than 30 or a ∆ measurement (diastolic BP – compartment pressure) <30. This patient's pressure difference is 25 which is strongly suggestive of compartment syndrome. The femur is in a large compartment and it is typically difficult to sustain compartment syndrome. More concerning areas are the anterior tibial compartment and the forearm.

A. Anterior talofibular ligament
The correct answer is anterior talofibular ligament (ATFL) injury. The anterior-posterior and oblique x-ray views of the right ankle demonstrate a normal mortise and no fractures. There is, however, right lateral ankle soft tissue swelling. Typically, the mechanism of injury helps determine the location of ligamentous injury. The most common mechanism is inversion of the plantar-flexed foot, leading to lateral ankle sprains due to injury of the anterior talofibular ligament (ATFL), the calcaneofibular ligament, and posterior talofibular ligament. Of the three ligaments, the ATFL is the most commonly injured.

B. Calcaneofibular ligament
This patient is presenting with an ankle sprain and with lateral ankle sprains, the most common ligament injured is the anterior talofibular ligament. The calcaneofibular ligament may also be injured, but isolated calcaneofibular ligament injury is uncommon.

C. Deltoid ligament
This patient is presenting with a lateral ankle sprain and the deltoid ligament is on the medial side of the ankle, is much stronger, and is much less prone to injury.

D. Tibiofibular syndesmosis
Injury to the tibiofibular syndesmosis is an uncommon, but significant, injury. Injury to this structure characterizes a “high” ankle sprain. However, the squeeze test of the tibia-fibula is reported negative, making this diagnosis less likely. The squeeze test involves compression of the fibula against the tibia at the mid-calf level, trying to reproduce pain while attempting to widen the syndesmosis between the distal tibiofibular space.

The X-ray demonstrates an anterior knee dislocation. It is important to differentiate between a knee dislocation (tibiofemoral) and patellar dislocation. The patellar dislocation is less severe and typically without other associated injuries. A knee dislocation may not always be present on arrival to the ED as spontaneous reduction can occur prior to arrival. However, even with spontaneous reduction, significant pain and soft tissue swelling remains. In an anterior knee dislocation surrounding vascular and nerve structures are at risk. The dislocation results in significant ligamentous injury. The neurovascular bundle running behind the knee is at risk. The life threatening injury is laceration of the popliteal artery within this bundle. In addition to lacerations of the vascular structure, dissection is also possible from the shear injury occurring during the trauma. The popliteal vein is the other vascular structure within the bundle. The common peroneal nerve is located within the bundle and the neurologic injury associated with an anterior dislocation. This dislocation is associated with an injury to the common peroneal nerve in 20 to 40% of patients. The common peroneal nerve arises from the L4-S2 nerve roots and branches into the deep and superficial peroneal nerves. These nerves supply sensation to most of the dorsum of the foot sparing the lateral most portion of the foot. The motor function of the common peroneal is dorsiflexion of the ankle.

Metatarsal fractures are responsible for one third of foot fractures. Fractures at the base of the metatarsal are uncommon in the first through fourth metatarsals. The isolated fracture at the base of the fifth metatarsal is common and management depends on which form of the two fractures occurs. The Jones fracture is a transverse fracture occurring in the diaphysis of the bone at least 1.5 cm distal to the end of the bone. The Jones fracture tends to displace with further weight bearing. With improper immobilization there is a higher percentage of nonunion of the fracture fragments. Therefore, patients should be immobilized in a posterior splint and given crutches for non-weight bearing ambulation. The pseudo-Jones fracture is an avulsion fracture of the tuberosity at the base of the fifth metatarsal. The injury often occurs as a result of a lateral ankle strain with tension at the attachment of the peroneus brevis tendon. These patients are treated with a compression dressing and weight bearing as tolerated. Providers may elect to give the patients a hard sole shoe.

The lateral radiograph shows a perilunate dislocation in which the lunate remains aligned with the distal radius, however the remaining carpal bones are dorsally displaced. There is significant ligamentous injury. The mechanism of injury is generally a fall on an outstretched hand (FOOSH). Patients complain of wrist pain and swelling, and tenderness is noted over the carpal bones on exam. If untreated, the patient is at risk for developing median nerve compression, avascular necrosis, compartment syndrome and long-term disability. A hand surgeon should promptly evaluate the patient with a plan for urgent open dislocation reduction.

Anterior shoulder dislocations are the most common type of shoulder dislocation. The axillary nerve is the neurologic structure most at risk for injury during a shoulder dislocation. Sensation over the deltoid muscle is the way in which axillary nerve function is tested on physical examination. Additionally, distal nerve function of the median, radial and ulnar nerves should be evaluated as part of the complete evaluation of the shoulder joint. It is important to document all findings of the neurovascular examination prior to any attempts as a baseline. Posterior dislocations are associated with significant injury 30% of the time to intrathoracic and mediastinal structures. These complications include: injury to the great vessels, tracheoesophageal fistula, pneumothorax and brachial plexus injuries.

This case describes a patient with an ankle syndesmosis injury which if not properly treated leads to chronic ankle instability and pain. The image shows widening of the tibio-fibular joint as well as a widened ankle mortise. This ankle requires non-weight bearing an urgent othopedic consultation for possible operative fixation.

It is difficult to identify cardiac tamponade by visual inspection only. Thus the first step should be opening the pericardium. Direct cardiac massage should be done after pericardium is opened and if no tamponade is found. Cross clamping of the aorta should be the next step if the patient still has no cardiac activity.

This clinical scenario depicts a patient with a tension pneumothorax. He has decreased blood pressure, decreased breath sounds, and, most important, an increased resistance to ventilation, which is the earliest sign of the development of a tension pneumothorax. Immediate decompression with a large-bore needle is the correct initial management in this condition.

Elevation of the right mainstem bronchus is suggestive of acute traumatic aortic disruption. Traumatic aortic disruption can result in immediate death if the degree of injury is severe, such as a complete transection. However, with less severe disruptions, the patient may survive and present to the ED. Prompt diagnosis and early intervention, can lead to a functional recovery.

Deviation of the trachea to the right (B), not the left suggests aortic injury. Deviation of the esophagus to the right (A), not the left suggests aortic injury. A left-sided hemothorax (D) suggests aortic injury, not a right hemothorax.

Two most common sites of aortic injury with blunt trauma are: Aortic isthmus and ascending aorta just proximal to the origin of the brachiocepahic vessels.

This patient has signs and symptoms of blunt cardiac injury. The most common chamber injured is the right ventricle as it lies most anterior in the thorax, immediately behind the sternum. Blunt cardiac injury results in myocardial contusion and “stunning” of the heart muscle. This can lead to dysrhythmias and heart failure. Cardiac contusion is most frequently caused by high-speed motor vehicle collisions or severe crush injuries. The most common etiology is a depressed sternal fracture. Symptoms of cardiac contusion include chest pain, shortness of breath, and palpitations. There is often external evidence of chest trauma including obvious depressed fractures of the sternum and steering wheel imprints. The diagnosis of significant blunt cardiac injury is made by electrocardiogram abnormalities (e.g. T wave inversions and frequent PVCs) and a serum troponin level. If either of these studies is abnormal, the patient should be admitted for telemetry monitoring.

This xray shows a Jefferson fracture, or a C1 burst fracture. These fractures occur with axial loading with vertical compression, an injury pattern that is common when a football player spears another player. When looking at the odontoid view of a c-spine film, the lateral masses of C1 shoulder align with the lateral parts of the C2 vertebral body. A Hangman’s fracture, or bilateral C2 pedicle fracture is best seen on a lateral view and shows C2 displaced anteriorly on C3. Odontoid fractures involve the odontoid process and are graded type I through type III depending on position.  Type II and III are both unstable fractures. Bilateral facet dislocation fractures are seen on lateral xrays of the c-spine and is characterized by anterior displacement greater than 50% diameter of vertebral body.

The correct answer is that this injury is associated with anterior cord syndrome. This patient has a flexion teardrop injury at C5 (note the wedge shaped fracture at the base of the vertebral body).  This is generally caused by extreme flexion and axial load, classically a diving injury. There is failure of the anterior column, often middle column, and disruption of the posterior ligamentous complex and the significant potential for cord injury from retropulsion of a fragment as a result.

Odontoid (dens) fractures are classified as Type I, II and III. Type I fractures are stable avulsion injuries to the tip of the odontoid. This patient has a Type II fracture, which is a fracture at the junction of the odontoid and body of C2. A Type III fracture is a fracture at the base of the the dens. Both Type II and III fractures are unstable because of ligamentous attachments. A bilateral C2 pedicle fracture is also known as a Hangman’s fracture and is seen on lateral xray as C2 being displaced anteriorly on C3. A teardrop fracture is an avulsion fracture of the anteroinferior portion of the vertebral body. Both of the former fractures patterns are unstable c-spine injuries.

A Clay-shoveler’s fracture, which is an avulsion of the spinous process of C6 or C7, is considered a stable cervical spine fracture. Other stable injuries include a unilateral facet dislocation and a type I odontoid fracture in which the tip of the odontoid is broken off is usually a stable cervical spine injury. This injury got its name from clay shovelers who were shoveling heavy clay that caused them to abruptly flex their neck while contracting their lower neck muscles. Now, most cases are due to direct trauma to the posterior neck.

Midline posterior bony cervical-spine tenderness is present if the patient reports pain on palpation of the posterior midline neck from the nuchal ridge to the prominence of the first thoracic vertebra, or if pain can be elicited with direct palpation of any cervical spinal process. Patients are considered intoxicated if any of the following is present: a recent history provided by the patient or an observer of intoxication or ingestion of an intoxicating substance, evidence of intoxication on physical exam (e.g., slurred speech, ataxia, dysmetria, or other cerebellar findings), or any behavior consistent with intoxication. Patients may also be considered intoxicated if tests of bodily fluids are positive for alcohol or drugs that affect the level of alertness. An altered level of consciousness can include any of the following: a GCS of 14 or less; disorientation to person, place, time, or events; an inability to remember three objects at five minutes; or a delayed or inappropriate response to external stimuli. A focal neurologic deficit is defined by any neurologic finding on motor or sensory exam. No precise definition of painful or distracting injury is possible. Determination of this is left to the treating clinician.Therefore, only the 64-year-old man with no posterior midline cervical spine tenderness nor pain when he turns his head to the left can be clinically cleared.

A 22-year-old man with no posterior midline cervical spine tenderness and the odor of alcohol on his breath (A), a 32-year-old man with no posterior midline cervical spine tenderness with a GCS of 14 (B) and an 18-year-old woman with no posterior midline cervical spine tenderness and mild numbness to her right arm (D) do not meet NEXUS criteria and require imaging.

What 3 components of the Canadian cervical spine rules are not present in the NEXUS cervical spine rules? Age, mechanism, neck rotational

A pulmonary contusion occurs most commonly from blunt trauma and is the result of a direct bruise to the lung parenchyma followed by alveolar edema and hemorrhage. Although the initial radiographic findings (patchy, irregular to dense pulmonary infiltrates over the injured area) may be non-diagnostic and initial measurements of gaseous exchange may be normal, pulmonary function may be compromised over the ensuing few hours. Subsequent radiographs taken over several hours may demonstrate irregular opacification of the pulmonary parenchyma in a non-lobular pattern. Chest CT scans may demonstrate a contusion. Uncomplicated pulmonary contusions typically develop over the first 24 hours and resolve in approximately one week. Patients with severe pulmonary contusions experience difficulty breathing and hypoxia. Repeat chest radiographs show an increasing opacity in the affected lung fields. The condition is exacerbated if extensive crystalloid fluid resuscitation has been performed. Blood gas evaluation reveals an increased a-A gradient. Treatment is initially supplemental oxygen administration to reverse hypoxia; however, subsequent intubation and ventilation with positive end-expiratory pressure may be required. Other adjunctive therapies include pulmonary toilet and analgesia.

Lung Contusion

Air within the pleural cavity (A), or pneumothorax, is part of the differential diagnosis for this patient but is less likely to occur than a pulmonary contusion with a blunt trauma mechanism. Pulmonary contusions tend to worsen over time (B) and the patient’s initial presentation can change rapidly as there is an increase in alveolar edema and hemorrhage. Lung involvement is usually localized to a segment or a lobe (D). Adult respiratory distress syndrome (ARDS) is associated with diffuse lung involvement.

This xray shows a Jefferson fracture, or a C1 burst fracture. These fractures occur with axial loading with vertical compression, an injury pattern that is common when a football player spears another player. When looking at the odontoid view of a c-spine film, the lateral masses of C1 shoulder align with the lateral parts of the C2 vertebral body. A Hangman’s fracture, or bilateral C2 pedicle fracture is best seen on a lateral view and shows C2 displaced anteriorly on C3. Odontoid fractures involve the odontoid process and are graded type I through type III depending on position.  Type II and III are both unstable fractures. Bilateral facet dislocation fractures are seen on lateral xrays of the c-spine and is characterized by anterior displacement greater than 50% diameter of vertebral body.

The correct answer is that this injury is associated with anterior cord syndrome. This patient has a flexion teardrop injury at C5 (note the wedge shaped fracture at the base of the vertebral body).  This is generally caused by extreme flexion and axial load, classically a diving injury. There is failure of the anterior column, often middle column, and disruption of the posterior ligamentous complex and the significant potential for cord injury from retropulsion of a fragment as a result.

The patient has an epidural hematoma. Epidural hematomas result from blunt trauma to the temporal or temporoparietal area with skull fracture and disruption of the middle meningeal artery. Blood pools in the potential space between the skull and dura mater, leading to a classic biconvex-appearing hematoma. Patients classically present with an initial loss of consciousness followed by a “lucid interval” and subsequent rapid neurologic decline as mass effect and herniation develops. Treatment is surgical evacuation of the hematoma.

The patient presents with minor head trauma and complaints consistent with a concussion and should have neurology follow up arranged. A concussion is a minor traumatic brain injury (TBI) that is often seen in MVCs and collision sports (football, hockey). It is typically caused by a rotational injury or an acceleration-deceleration injury. Patients will present with a number of non-specific symptoms including headaches, dizziness, confusion, amnesia, difficulty concentrating, and blurry vision but do not have focal neurologic findings. Despite the absence of severe intracranial injury, patients can have chronic and debilitating symptoms from concussions. Neurology referral is recommended, as patients should have functional testing and tracking of their symptoms for resolution. It is vital to council patients to avoid contact sports or activities that increased the risk of recurrent injury as these patients are at risk for more severe injury with second impact.

Odontoid (dens) fractures are classified as Type I, II and III. Type I fractures are stable avulsion injuries to the tip of the odontoid. This patient has a Type II fracture, which is a fracture at the junction of the odontoid and body of C2. A Type III fracture is a fracture at the base of the the dens. Both Type II and III fractures are unstable because of ligamentous attachments. A bilateral C2 pedicle fracture is also known as a Hangman’s fracture and is seen on lateral xray as C2 being displaced anteriorly on C3. A teardrop fracture is an avulsion fracture of the anteroinferior portion of the vertebral body. Both of the former fractures patterns are unstable c-spine injuries.

This patient has sustained a Zone II neck injury. He is demonstrating signs of impending airway obstruction with an expanding anterior neck hematoma, dysphagia, and dysphonia. The primary focus in the care of this patient and any other patient presenting following a traumatic injury should be the ABCs. This particular patient should be intubated right away: he is at risk for rapid deterioration and respiratory failure. Indications for establishing a definitive airway in the setting of penetrating neck trauma include respiratory distress, altered mental status, bloody secretions in the oropharynx, subcutaneous emphysema, expanding hematoma, and tracheal shift. Other signs of potential airway compromise include dysphagia and dysphonia. Orotracheal intubation is preferred in penetrating neck injury, but backup airway techniques should be available. If quickly available, awake fiberoptic intubation may be considered.

The patient’s presentation is critical. As soon as the airway is established, he should be transported immediately to the OR. Performing angiography would inappropriately delay management. All symptomatic patients with penetrating injuries to Zone II require surgical exploration.

Again, sending the patient for a CT scan would delay appropriate management. Additionally, CT is more appropriate in the evaluation of blunt trauma.

Cricothyrotomy should be avoided when an anterior neck hematoma is present. If the patient were more stable on arrival, intubation could be delayed until the patient reached the OR.

The treatment and amelioration of increased intracranial pressure (ICP) is one of the most important steps in the management of the multiple trauma patient. Mannitol is very effective, with a slightly delayed effect on the oncotic forces at work within the cranial cavity. Indicated in patients with impending herniation or evidence of increased ICP from trauma, mannitol is given as a bolus to lower ICP via osmotic diuresis and increase plasma expansion. A continuous mannitol drip can increase the chance of hypovolemia and is thus not recommended.

Hyperventilation after intubation has been used as a rapid intervention to lower ICP. It can be used for impending herniation or as a lifesaving therapeutic measure. But more recent studies indicate that patients with traumatic brain injury have a worse prognosis if hyperventilation is used in any prolonged manner, and that it should be avoided especially in the first 24 hours.

Neuromuscular paralysis is part of the process of rapid sequence intubation, but it does not in itself contribute to reduction of ICP. Successful intubation to manually control the patient’s respiratory rate and ventilation volume is made more successful with the use of neuromuscular blockers. Complete paralysis allows mechanical hyperventilation while the patient is on the ventilator.

The value of steroids in the care of patients with increased ICP from other processes, including cancer, is debatable. Several large studies have shown that steroids are not effective in treating patients with traumatic brain injury.

A. Admission to the hospital
This patient is presenting with a basilar skull fracture, evidenced by the CSF fluid coming from his ear. Recommendations are that all of these patients should be admitted to the hospital for monitoring. A recent cochrane review found no evidence that routine antibiotics were indicated for CSF leaks in these patients however. Source: Ratilal BO, Costa J, Pappamikail L, Sampaio C, Antibiotic prophylaxis for preventing meningitis in patients with basilar skull fractures. Cochrane Database Syst Rev. 2015;4:CD004884. PMID: 25918919

B. Admission and systemic antibiotic therapy
While this patient should be admitted for his basilar skull fracture, antibiotics are not indicated. A recent cochrane review found no evidence that routine antibiotics were indicated for CSF leaks in these patients however. Source: Ratilal BO, Costa J, Pappamikail L, Sampaio C, Antibiotic prophylaxis for preventing meningitis in patients with basilar skull fractures. Cochrane Database Syst Rev. 2015;4:CD004884. PMID: 25918919

C. Admission and systemic steroids
While this patient should be admitted for his basilar skull fracture, steroids are not indicated

D. Discharge with oral antibiotics
This has a basilar skull fracture and CSF leak, and should be admitted for monitoring.

Complex facial fractures may be classified into the Le Fort system of fracture patterns. Three types exist. Type I Le Fort fractures are transverse fractures through the base of the maxilla and often involve the roots of the teeth. It may be unilateral and bilateral. The upper teeth may be grasped and rocked independent of the midface, indicating discontinuity with the maxilla. Type II Le Fort fractures are often bilateral and are characterized by pyramidal fractures that extend through the body of maxilla, orbital floor, nasal bones, hard palate, and lacrimal bones. The nasal unit and maxilla may be grasped and move as a unit relative to the orbital complexes and lower face. Type III Le Fort fractures are considered complete craniofacial disjunction as the fracture extends from the nasal bridge traveling posteriorly along the ethmoid bone, which comprises the medial orbital wall, and continues through the inferior and lateral orbital walls and frontozygomatic suture. The sphenoid bone is often involved with type III fractures, and cerebrospinal fluid (CSF) leak may occur. CSF may also leak from involvement of the cribriform plate of the ethmoid bones. Le Fort fractures are best seen with computed tomography. Depending on the extent of the injury, Le Fort fractures often require management of a multidisciplinary team and may necessitate consultation to otolaryngology, plastic and reconstructive surgery, dentistry and neurosurgery if a CSF leak is present.

A type II Le Fort fracture involves the central maxilla (A), nasal bridge, lacrimal bones, hard palate (C), and orbital floor. It often occurs bilaterally and in a pyramidal pattern. Fractures of the mandibular condyle (D) are not included in the Le Fort classification of midface fractures.

Bedside intraocular ultrasound performed by an emergency physician is a very useful tool for rapidly diagnosing many intraocular conditions. Dislocated lens, foreign body, and detached retina can be identified by ultrasound. It has not been demonstrated as useful in the diagnosis of orbital compartment syndrome caused by a retrobulbar hemorrhage.

Heat emergencies represent a continuum of disorders that range in severity from heat cramps to heat exhaustion to life-threatening heat stroke. In most circumstances, heat emergencies can be avoided through common sense, public education, and prevention. People most at risk for heat injuries include athletes, military personnel, and laborers who work outdoors in the heat. Classic heat injury, as is the case with this patient, usually occurs during periods of high environmental heat stress. Physical exertion is not required if environmental temperatures and humidity create a situation where heat gain overwhelms native heat losses. Exertional heat injury usually affects individuals who are participating in athletic events in conditions of high heat stress. Clinical features are what determine the severity of heat illness. This patient is presenting with symptoms characteristic of heat exhaustion. Other symptoms can include muscle cramps, headache, and vomiting. On physical examination of patients with heat exhaustion, the temperature may be normal or elevated. However, patients with heat exhaustion will not have mental status changes. Mental status changes are a sign of heat stroke which can be life-threatening.

Dry skin, or anhidrosis (A), can classically be found in patients with heat stroke but this is not a requirement for the diagnosis since patients with severe heat illness can also present with diaphoresis. Heat exhaustion is characterized by the inability to maintain adequate cardiac output due to strenuous exercise and environmental heat stress. Acute dehydration may be present. Athletes with heat exhaustion have difficulty continuing with exercise. Other signs of heat exhaustion include hypotension (B), syncope, and tachycardia (D). The presence of these factors does not necessarily portend severe complications from the illness. Severe heat illness, heat stroke, presents with neurological symptoms such as hallucinations, seizure, mental status changes, or coma.

The class Arachnida contains the largest number of venomous species known, but most are not harmful to humans. Humans fear spiders and scorpions, but of this class of species ticks probably cause the greatest morbidity. One of the more venomous spiders known is the black widow spider or Latrodectus species. They are found throughout the United States, except Alaska. Symptoms of a black widow spider bite include a pinprick sensation followed by local redness and swelling, but sometimes the bite is not felt. Over the next hour, patients develop dull cramping in the area of the bite that eventually spreads to the entire body. Pain is centered in the chest in patients who suffer an upper extremity bite, and pain is centered in the abdomen in patients who suffer a lower extremity bite. The abdomen may become boardlike and can mimic pancreatitis, appendicitis, or a perforated peptic ulcer. Signs and symptoms usually abate within a few hours and definitely resolve in two to three days. Management is supportive with benzodiazepine treatment for muscle spasms.

Symptoms of a brown recluse spider (B) bite include local burning pain at the site of the bite. After a few hours, a bleb forms in the center of the bite with a surrounding erythematous ring. The area can look like a target sign or a bull’s eye. Over the next few days, the bleb darkens and begins to necrose with eventual involvement of the underlying subcutaneous fat along with the skin. Systemic symptoms such as fever, malaise, vomiting, and rash can develop and lead to shock in severe cases, although fatalities are rare. This patient does not have a bite characteristic of a brown recluse spider. A scorpion (C) sting is characterized by immediate pain at the site of the sting. Over some time, patients can develop numbness and weakness locally and will have heightened sensitivity in the sting area. Systemic symptoms such as restlessness, vomiting, muscle spasms, nystagmus, and myoclonus can develop in severe cases but are more rare. Scorpion sting symptoms can mimic those found in patients with black widow spider bites but are much less common. Most tarantulas (D) are nontoxic. They are unusual in that their abdominal hairs can be thrown and embedded in human skin, leading to allergic reactions. There is not a toxic bite. The patient in this question is not presenting with allergic reaction symptoms.

Decompression sickness occurs due to the liberation of gas bubbles associated with a decrease in ambient pressure. This can occur in divers breathing compressed air as well as high altitude pilots or astronauts. The gas bubbles likely obstruct blood flow, leading to direct tissue ischemia. They also activate a variety of inflammatory processes, leading to thrombosis and capillary leaking. Symptoms of decompression sickness typically occur minutes to hours after surfacing. Decompression sickness can include pain syndromes involving the joints (“the bends”) as well as more serious manifestations including pulmonary (“the chokes”), cardiovascular, and neurologic symptoms (“the staggers”). Treatment of decompression sickness is similar to the treatment of an arterial air embolism and includes administration of oxygen, increasing tissue perfusion with intravenous fluids, and rapid decompression with hyperbaric oxygen.

Arterial air embolism (A) is an example of a barotrauma of ascent and results from entry of air into the arterial system with resultant embolization. The brain is the most commonly affected organ. Arterial air embolism should be suspected in any diver with loss of consciousness upon surfacing. Inner ear barotrauma (C) is an example of barotrauma of rapid descent or ascent and results from rupture of the round window or tearing of the vestibular membrane due to a forceful Valsalva maneuver done during descent to clear the ears. Symptoms include vertigo (as seen in the patient above) but this condition is easily differentiated from decompression sickness due to the onset of symptoms during descent rather than after surfacing. Nitrogen narcosis (D) occurs with deep dives and includes symptoms such as loss of fine motor skills and higher-order brain functions, resulting in bizarre and dangerous behavior. Presentation is similar to alcohol intoxication.

Atrial fibrillation in hypothermia tends to be relatively benign and resolves spontaneously with rewarming. Persistent atrial fibrillation after complete rewarming is unlikely to be due to hypothermia and may suggest an underlying medical pathology. Cardioversion increases the risk of ventricular fibrillation and is contraindicated unless the patient is unstable. Anticoagulation for temporary atrial fibrillation is not indicated and could worsen the coagulopathy already present in hypothermia.

This patient presents with rhabdomyolysis after an electrical injury and should be treated with aggressive intravenous hydration. Electrical injuries are common and are the cause of about 5% of burn unit admissions and 6% of occupational fatalities. The extent of the injury is related to the type of circuit (alternating current (AC) versus direct current (DC)), the resistance, amperage, duration of contact and voltage. The initial exposure to electricity can cause severe burns spreading from the point of impact. Additionally, the energy from the shock is transmitted into the body and can cause significant muscle breakdown. Breakdown is increased if the patient experiences tetany or prolonged exposure to the electrical source. The classic finding of rhabdomyolysis is a urine dip that is positive for blood with only scant or no RBCs on microscopy. The urine dipstick falsely reports myoglobin as hemoglobin in this case. A serum creatinine kinase level should be obtained. Initial treatment is with aggressive fluid resuscitation to maintain urinary output as myoglobin accumulation can lead to renal failure. Electrolyte abnormalities (specifically hyperkalemia from cellular breakdown) should be closely monitored and treated as well.

A CT scan of the abdomen (A) is not necessary to look for a bleeding source. Intravenous antibiotics (B) are not necessary as this urinalysis does not indicate the presence of infection. Packed red blood cells (D) are not needed at this time as the patient does not exhibit signs of bleeding.

The partial pressure of oxygen decreases as barometric pressure decreases at altitude. At 8,000 feet or greater above sea level, the environment becomes hypoxic and high-altitude syndromes can occur due to hypoxia. These include acute mountain sickness (AMS), high-altitude pulmonary edema, high-altitude cerebral edema, retinopathy, and certain neurologic syndromes. High-altitude cerebral edema (HACE) is the most severe form of acute mountain sickness. At altitude, cerebral vasodilation occurs and leads to increased blood flow and blood volume. This is due to a leaky blood-brain barrier either from lack of autonomic autoregulation or increased vascular permeability, or a combination of the two. HACE is characterized by progressive global cerebral dysfunction and causes confusion, altered mental status, and ataxia. Ataxia is a cardinal and early sign of HACE, and all patients with acute mountain sickness should be monitored for ataxia. Other features, such as headache, nausea, or vomiting, may be absent. Retinal hemorrhages are also common, and cranial nerve palsies of the third and sixth cranial nerves may occur due to increased intracranial pressure. Concomitant pulmonary edema is common. Death from HACE is due to brainstem herniation, so early identification and management are critical. The highest priority is descent. If this is not possible, temporizing measures (though often unavailable) include supplemental oxygen, corticosteroids, and use of a portable hyperbaric oxygen chamber. Computed tomography of the head may demonstrate white matter hyperattenuation more than gray matter with effacement of the sulci and flattening of the gyri.

This patient presents with signs and symptoms consistent with a left middle cerebral artery stroke as well as subcutaneous emphysema that developed during ascent from diving. Any focal neurologic deficit that results during ascent or immediately thereafter should be considered a cerebral arterial air embolism until proven otherwise. Rapid uncontrolled ascent against a closed glottis causes the volume of gas in the lungs to expand according to Boyle’s law (pressure and volume of a gas are inversely related at a constant temperature). As this gas expands, it can lead to pulmonary barotrauma, including pneumothorax, pneumomediastinum, (as indicated by this patient’s subcutaneous emphysema on exam), and alveolar rupture. Alveolar rupture leads to gas leakage into the pulmonary veins, which can then move into the systemic circulation and lodge in distal arterioles as arterial gas emboli. Cerebral gas embolism presents with typical stroke symptoms and is one of the most serious complications of pulmonary barotrauma. Air embolization can be prevented by exhaling during ascent, which prevents the rapid expansion of volume within the lungs as pressure decreases. Treatment includes fluid resuscitation and rapid recompression with 100% hyperbaric oxygen. Hyperbaric oxygen works by decreasing the size of the air embolism as well as easing washout of other gases by increasing the diffusion gradient for nitrogen from the air embolism to plasma.

Barotitis (B), or ear barotrauma, is the most common diving disorder and results from unequalized increasing pressure on the tympanic membrane on descent. Symptoms include unilateral ear pain and fullness, as well as vertigo and disorientation from rupture of the tympanic membrane and uneven caloric stimulation of the middle ear. Treatment is conservative. Decompression syndrome (C), or “the bends,” usually occurs within six hours after ascent. It results from the expansion of inert gas that dissolved in tissues during descent. As the pressure of these inert gases exceeds atmospheric pressure, it can exit tissue in the form of bubbles, which often lodge in veins, leading to localized venous obstruction and inflammatory cascades. Patients either present with significant pain (type I) or ascending paresthesias or paralysis (type II). Treatment is the same as for arterial gas embolization. Nitrogen narcosis (D) results from the increased partial pressure of nitrogen in CNS tissue and therefore occurs at significant depth. Symptoms are similar to alcohol intoxication and include altered coordination and impaired judgment.

The ECG demonstrates the presence of J waves or Osborn waves which are seen in hypothermia. One of the first cardiac effects of hypothermia is bradycardia secondary to decreased firing of the cardiac pacemaker cells in cold temperatures. Osborn waves may appear at any temperature below 32°C. The waves are an upward deflection at the terminal portion of the QRS complex. They may represent abnormal ion flux in cold temperatures along with delayed depolarization and early repolarization of the left ventricular wall. As temperatures continue to drop, the ECG will demonstrate prolonged intervals: PR, followed by QRS and then QTc.

Both diabetic ketoacidosis (A) and digoxin toxicity (B) may lead to hyperkalemia. In diabetic ketoacidosis, hyperkalemia develops as a result of the acidic pH in the blood and the transport of hydrogen ions intracellularly in exchange for a potassium ion. Digoxin toxicity poisons the cellular Na+/K+ ATPase resulting in elevated extracellular levels of potassium. The ECG manifestations of hyperkalemia begin with peaked T waves. Multiple other findings eventually develop including a shortened QT interval, ST depression, bundle branch blocks, widened QRS, prolonged PR interval, flattened T wave and ultimately a sine wave. Hyperparathyroidism (C) may lead to hypercalcemia. In hypercalcemia, the ECG shows a shortened QT interval, flattened T waves and QRS widening at very high levels.

Hepatic injury, as denoted by aspartate aminotransferase 2100 U/L, alanine aminotransferase 1900 U/L, is so extremely common in heat stroke that its absence should push one to reconsider the diagnosis. The hallmarks of heat stroke include severe hyperthermia (> 40.5oC) and neurologic dysfunction. Neurologic dysfunction occurs due to a progressive increase in heat stores because of the body’s decreasing ability to perfuse the distal extremities. As the heat stores increase, intracranial pressure increases with a subsequent decrease in cerebral blood flow. There are two types of heat stroke, each with their own patient population and clinical presentation. Classic heatstroke is due to exogenous heat production, while exertional heatstroke is due to endogenous heat production. Patients with classic heat stroke are commonly elderly with chronic diseases or those with limited access to shelter against the heat or oral hydration that present with symptoms usually in the setting of a prolonged, severe heat wave. Patients with exertional heat stroke are commonly young, athletes, or military personnel that present with symptoms after strenuous exercise in the heat. Classic heat stroke patients are usually anhidrotic, while those with exertional heat stroke tend to present diaphoretic. Diagnosis is primarily clinical, though laboratory testing should always be performed, as end-organ damage is common and can help further differentiate the types of heat stroke. Classic heat stroke tends to cause respiratory alkalosis, mild coagulopathies, mild creatinine kinase elevations, and elevated troponin. It is more common to see lactic acidosis, disseminated intravascular coagulation, rhabdomyolysis, and hypoglycemia in those with exertional heat stroke. With a mortality rate of 21–63%, treatment must be immediate and aggressive. Cooling is the mainstay of treatment with the primary goal to maximize evaporative cooling and prevent heat-generating shivering. Antipyretics are not useful in cooling, as they counteract hypothalamic-mediated hyperthermia and not environmental hyperthermia. Alongside cooling, immediate supportive treatment with intravenous fluids, supplemental oxygen, and reversal of coagulopathies should be started.

Acute kidney injury, as denoted by blood urea nitrogen 30 mg/dL, creatinine 1.5 mg/dL (B), and elevated troponin 0.8 ng/mL (D) can occur in classic heat stroke but are rare in exertional heat stroke. Rhabdomyolysis, as denoted by creatinine kinase 2500 U/L (C), is common in exertional heat stroke and less so in classic heat stroke. While each of these laboratory findings is possible in heat stroke, hepatic damage is still the most common finding.

Sacroiliitis is an inflammatory disorder of the sacroiliac joint in the posterior pelvis. It is a feature of spondyloarthropathies such as ankylosing spondylitis. Patients may present with low back pain or pain in the buttock or leg. There is tenderness to palpation of the sacroiliac joint but no pelvic instability. Patients with ankylosing spondylitis are usually men less than 40 years of age and often report back pain and stiffness that is worse upon waking up and improves with activity throughout the day. Plain films of the spine may demonstrate “squaring” of the vertebral bodies (bamboo spine). Referral to a rheumatologist and treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) are recommended. Emergent causes of low back pain (e.g., spinal cord compression, spine infection, trauma) should be considered and screened with directed history and physical examination. Concerning features of back pain include history of trauma, recent surgery, intravenous drug use, old age, history of cancer, fever, focal neurologic deficits (e.g., weakness, numbness), urinary or bowel dysfunction, and unexplained weight loss. Patients with these features should be worked up for emergent causes of back pain such as malignancy, cord compression, or infection with advanced imaging, blood cultures, and potentially consultation to a spine surgeon.

Central cord syndrome (A) is the most common spinal cord syndrome and presents with upper extremity weakness greater than lower extremity weakness. It is caused by extreme neck extension. Pott’s disease (B) is vertebral osteomyelitis. Patients usually present with fever and other signs of infection such as tachycardia, leukocytosis, and erythema overlying the area of infection. A psoas abscess (C) is an infected fluid collection of the iliopsoas muscle compartment. Patients are usually ill-appearing and septic with fever and back pain, flank pain, or lower abdominal pain that does not improve throughout the day.

Fluoroquinolone drugs, including levofloxacin, have been associated with spontaneous tendon ruptures. Fluroquinolones are a commonly prescribed antibiotic class. The class includes ciprofloxacin, moxifloxacin and levofloxacin. The fluoroquinolone class of drugs has a number of side effects, the most serious of which are prolongation of the QTc and spontaneous tendon rupture. Tendon rupture appears to be more common in older patients. The overall risk is between 0.1 – 0.4%. These drugs are discouraged for use in pregnant women and children secondary to their effect on cartilage.

Sciatica is a lumbosacral radiculopathy that is caused by compression of the spinal nerve root(s). 90% of all cases are due to disc herniation, although spinal stenosis, spondylolisthesis, and piriformis syndrome are other notable causes. Symptoms typically develop suddenly during physical activity and consist of back pain radiating down the leg, though the pain may radiate bilaterally. Weakness and numbness in the affected limb may also be present. The straight leg raise (SLR) is a good screening test for sciatica with 92% sensitivity and 28% specificity. The patient’s affected leg is extended and passively elevated. Pain elicited in a sciatic nerve distribution past the knee indicates a positive test. Pain elicited in the back alone is not considered positive. The crossed straight leg raise compliments the straight leg raise well in that it has a sensitivity of 28% and specificity of 90%. The crossed straight leg raise is performed by passively elevating the extended unaffected leg. A positive test is signified by pain evoked in a sciatic nerve distribution in the affected leg. Atraumatic sciatica does not necessitate imaging. Imaging should be sought when there is concern for infection or malignancy or when significant neurologic deficits are present (e.g., marked weakness, numbness, or bowel/bladder dysfunction). MRI is the preferred imaging modality in these cases. Treatment of sciatica is largely symptomatic with the use of non-narcotic analgesics, preferably nonsteroidal anti-inflammatory drugs, and activity as tolerated. Steroids and neuropathic pain medications have not shown significant efficacy in sciatica. With conservative management, most patients’ symptoms resolve after six weeks. Surgical treatment via discectomy is reserved for patients who have failed conservative management. However, while studies have shown short-term improvement in pain control after surgery, no difference in long-term pain control has been found between conservatively and surgically managed patients.

Crossed leg raise alone (A) has good specificity, but poor sensitivity. Crossed straight leg raise and straight leg raise (B) should be used together, however the straight leg test has the highest sensitivity and the crossed straight leg raise has the highest specificity. Straight leg raise alone (C) has good sensitivity, but poor specificity.

This young patient with low back pain and morning stiffness that improves with exercise most likely has ankylosing spondylitis. Ankylosing spondylitis is an inflammatory arthritis that primarily affects the spine and is associated with human leukocyte antigen (HLA-B27). Diagnosis is made using a combination of clinical symptoms, lab testing, and radiographic findings suggestive of sacroiliac joint pathology. Classically, X-ray imaging shows fusion of vertebrae (“bamboo spine”) as the peripheral fibers of the intervertebral annulus fibrosus discs ossify. However, symptoms can be present up to 10 years before radiographic evidence of the disease is apparent. Patients generally present with arthritic symptoms most apparent in the lower back, but can also have enthesopathy (as in this patient’s Achilles tendon pain), uveitis, and fibrosis of the upper lobes of the lung. The sacroiliac joint can be tested by flexing, abducting, and externally rotating one leg (FABER test). If pain is elicited on the posterior, contralateral side, it is suggestive of sacroiliac joint pathology. If pain is elicited on the anterior, ipsilateral side, it is suggestive of pathology within the hip. The mainstay of treatment is nonsteroidal anti-inflammatory drugs (NSAIDs) along with tumor necrosis factor antagonist medications.

Osteoarthritis (B) can also cause back pain, but generally affects older patients and usually improves with rest rather than worsening. The sacroiliac joints are rarely affected. Rheumatoid arthritis (D) can cause arthritic pain in younger individuals with morning stiffness, but usually affects small joints (hands, feet, and cervical spine). Osteofibrous dysplasia (C) is a fibrovascular defect of the long bones that leads to replacement of cortical bone with fibrous tissue. The disease is usually painless and spinal involvement is extremely rare.

Rhabdomyolysis is the result of the breakdown of skeletal muscle releasing the intracellular contents into the bloodstream. In minor cases, patients are asymptomatic but with severe cases the condition is life threatening with severe electrolyte disturbance and renal failure. The ultimate final pathway in rhabdomyolysis is the accumulation of intracellular cytoplasmic calcium which leads to myocyte destruction. This occurs as a result of direct cell membrane damage and ATP depletion. The hallmark of diagnosis is the presence of elevated serum creatine kinase and myoglobinuria. Management of rhabdomyolysis involves treating or removing the underlying cause, correcting electrolyte abnormalities and prevention of renal failure. Intravenous fluid administration is the mainstay of therapy titrating to a goal urine output of 3 mL/kg/hr.

Standard therapy used to include alkalinization of both serum and urine with the administration of sodium bicarbonate. An alkaline pH of the urine (A) above pH of 6.5 is the goal in alkalinization. This is not achieved with intravenous normal saline as described in the vignette. Intravenous fluid should be continued until clearance of the plasma creatine kinase. Precise guidelines do not exist, but the goal CK should be a level less than 1000 U/L, not 15,000 U/L (B). A creatinine less than 1.0 mg/dL (C) is not a standard goal of hydration for rhabdomyolysis. If renal failure is present, hydration will continue until improvement although no specific value is identified as the target.

The subacromial space is an area between the coracoacromial arch and the greater tuberosity of the humerus. It contains the long head of the biceps tendon, the supraspinatus tendon, and the subacromial bursa. Subacromial bursitis is most often an overuse injury due to chronic impingement. Patients who participate in frequent overhead activity are most at risk. The most common complaints are pain with overhead movement and difficulty finding a comfortable position at night due to pain. On physical examination, they likely will have a positive Neer impingement sign (pain with arm in 180 degrees forward flexion, followed by internal rotation) and Hawkins impingement sign (pain with arm in 90 degrees abduction, elbow flexed at 90 degrees, followed by internal rotation). Initial treatment is conservative with rest, nonsteroidal anti-inflammatory drugs and activity modification. Some patients may need additional physical therapy or a subacromial bursa steroid injection. Those with continued pain may proceed to further imaging with ultrasound or MRI and consideration of decompression surgery with orthopedics.

Acromioclavicular separation (A) involves partial or complete tearing of the acromioclavicular and coracoclavicular ligaments. It follows an injury to the shoulder, most often a direct or blunt hit to the shoulder. On examination, there is often a notable deformity at the AC joint along with associated tenderness to palpation. Adhesive capsulitis (B) or “frozen shoulder” is an inflammatory reaction within the capsule and synovium of the glenohumeral joint. It results in significant global loss of active and passive range of motion of the shoulder (forward flexion, abduction, external rotation and internal rotation). It can occur following an injury or spontaneously in those with autoimmune disorders such as diabetes or hypothyroidism. Full-thickness supraspinatus tear (C) most often occurs following an acute injury and presents with an inability to abduct the arm and a positive empty can test (unable to hold arm in 90 degrees of abduction with internal rotation).

auda equina syndrome results from compression of the conus medullaris and nerve roots, most commonly fromherniated discs, bone fragments, hematomas, epidural abscess, tumors, or vascular insufficiency. The compression classically occurs below L1. Patients present with complaints of low back pain, lower extremity pain, paralysis or paresthesia, saddle anesthesia, impotence, and bowel or bladder dysfunction. Urinary retention is the most consistent finding with a sensitivity of 90%. A thorough history about recent spinal procedures, trauma, anticoagulation, intravenous drug use, and malignancy help aide in determining the cause. On physical examination, lower extremity deficits, whether sensory or motor, may be present. Frequently asymmetric and unilateral signs and symptoms are present. Absent or decreased rectal tone and bulbocavernosus reflexes and a palpable bladder due to urinary retention may also be present. Patients with a suspicious history and physical concerning for cauda equina require emergent MRI imaging for evaluation. CT myelogram may be utilized in patients unable to have an MRI performed. Treatment consists on surgical decompression by a spine surgeon.

Fecal incontinence (A), motor deficits (B), and saddle parenthesis (C) all may or may not be present in a patient with cauda equina syndrome, but none of these symptoms are the most sensitive.

Rhabdomyolysis is the breakdown of striated muscle resulting in release of intracellular contents into the extracellular fluid and circulation. This can result in a spectrum of disease severity ranging from asymptomatic elevation of muscle enzymes to life-threatening electrolyte imbalances, acute renal failure, multiorgan failure, and death. There are several causes of rhabdomyolysis such as exertion, drugs and toxins, trauma, infections, electrical current, hypoxia, hyperthermia, or metabolic disorders. However, in the United States, it occurs most often due to prolonged muscle compression in the intoxicated patient who lays motionless or in the elderly with dementia following a fall. Patients classically present with complaints of muscle weakness, myalgias, and tea-colored urine. Physical examination may reveal muscle weakness, tenderness and swelling, or skin color changes, such as blistering or discoloration. Compartment syndrome should be considered if the exam reveals a firm compartment, pain on passive extension, and neurovascular compromise. The diagnosis of rhabdomyolysis can be made with a creatine kinase level greater than five times normal. Other laboratory abnormalities may include an elevated serum myoglobin, myoglobinuria, large blood on urinalysis with the absence of red blood cells, hyperkalemia, hyperphosphatemia, hypocalcemia, hyperuricemia, and hypoalbuminemia. The mainstay of treatment is with high volumes of normal saline to maintain a urine output of 200 to 300 mL/hr. Urine alkalinization theoretically enhances renal myoglobin clearance and can be achieved by adding bicarbonate to the intravenous fluids to maintain a urine pH greater than 6.5. This can be used as an adjunct, however, there are potential adverse effects such as hypernatremia, fluid overload, and exacerbation of hypocalcemia.

Elevated creatinine (B) may be seen in rhabdomyolysis that is complicated by acute renal failure, however, it is not diagnostic. Hypokalemia (C) is not diagnostic of rhabdomyolysis. Potassium levels are typically elevated in rhabdomyolysis. Large blood on urinalysis with red blood cells present (D) is not diagnostic of rhabdomyolysis, however, large blood on urinalysis with the absence of red blood cells is diagnostic of rhabdomyolysis and is due to myoglobinuria.

Pain with passive stretch of the effected compartment is the most common symptom early in compartment syndrome. Compartment syndrome develops when pressure builds within a confined anatomical space. Increasing pressure leads to decreased perfusion compromising tissue. Tissue ischemia eventually leads to death of muscle, nerve and bone tissue. Although it is typically associated with major trauma and crush injuries, it can develop after a relatively minor injury. Any compartment that is prescribed by fascial planes can develop compartment syndrome. However, the lower extremities are the most common location due to their higher risk for injury and their relatively low-volume compartments. Long-bone fractures account for 75% of all traumatic compartment syndromes. Patients will present with pain that is often out of proportion to examination.

Although pallor (B), parasthesias (C), pulse deficit (D) and paralysis are four of the classic symptoms, pain with passive stretch of the muscles involved is the most common early finding. Early recognition is key as prompt decompression can be limb saving.

Grade IA recommendation is for early activity and to avoid bed rest (by RCT).

The first choice for patients with mild to moderate back pain should be acetaminophen or a nonsteroidal anti-inflammatory drug (NSAID) like ibuprofen or naprosyn. In patients with severe pain, opiate medications may be necessary. However, it is important to note that no studies have demonstrated the superiority of one pain medication (or class of medication) over another in the treatment of back pain. Patients with milder symptoms should initially be treated with acetaminophen or an NSAID. These medications are well tolerated in short courses with minor side effects. NSAIDs have not been shown to be superior to acetaminophen.

The rim sign represents additional overlap between the glenoid and humeral head.
The light bulb sign is due to internal rotation of the humeral head that moves the greater tuberosity out of its normal lateral position on the AP view, causing the head to look more circular.
The trough line sign is an additional line within the humeral head that represents the trough of an impaction fracture (reverse Hill–Sachs deformity).

Clavicle fractures are the most common fracture in children. 80% of clavicle fractures are in the middle third of the clavicle. Most heal without fixation and very rarely require reduction in the ED. A sling is equivalent to a figure-of-eight splint for immobilization of a clavicle fracture

Pseudogout generally affects middle-aged and elderly patients. Pseudogout is a type of crystal-induced synovitis that is caused by calcium pyrophosphate crystals. These crystals are positively birefringent and are rhomboid shaped. Patients will present complaining of joint pain, swelling, and redness. Joints most commonly affected are the knee, wrist, ankle, and elbow. Pseudogout is a type of inflammatory arthritis that is diagnosed and confirmed by synovial fluid analysis. Synovial fluid for an inflammatory arthritis will have a white blood cell count between 200 and 50 000 with a predominance of neutrophils (generally greater than 50%). The appearance of the synovial fluid will be cloudy and yellow with positive birefringent, rhomboid shaped crystals. Treatment includes the use of nonsteroidal anti–inflammatory drugs and opioid analgesics. Corticosteroids are an option in patients with a history chronic kidney disease or patients the provider thinks may be of benefit. Avoid corticosteroids in uncontrolled diabetics given the risk of worsening hyperglycemia. Colchicine is not routinely used due to its side effect profile, however, it may be used in refractory cases or in cases where NSAIDs and corticosteroids cannot be used.

Gout (A) is also a type of inflammatory crystal-induced synovitis, however, it is caused by uric acid crystal deposition. Gout generally affects middle-aged and elderly patients. Uric acid crystals are needle shaped and are negatively birefringent. Patients will present complaining of arthritis, edema, and erythema. The joints most commonly affected are the great toe, tarsal joints, and knee. Synovial fluid analysis will be similar to pseudogout, as both are an inflammatory arthritis. Differentiating the two is based on the characteristic crystal formation. Thus, crystal analysis is imperative to the correct diagnosis. However, treatment remains the same as with pseudogout and so synovial fluid analysis is performed more to rule out septic arthritis. Osteoarthritis (B) is a symmetric and chronic polyarticular joint disease distinguished by the lack of constitutional symptoms. Patients may present with acute exacerbations of monoarticular pain that consists on joint pain and inflammation. Synovial fluid analysis will demonstrate a white blood cell count of less than 200 cells with fewer than 25% neutrophils. The synovial fluid will be have a clear and transparent appearance without crystals. Treatment consists of rest and analgesics. Septic arthritis (D) is a condition that can rapidly lead to irreversible joint destruction if not recognized and treated. Patients will typically present with a monoarticular arthritis and may have associated fever, chills, and malaise. Septic arthritis should be differentiated from periarticular processes such as cellulitis, bursitis, and tendinitis. A true arthritis will produce pain that is exacerbated through active and passive range of motion. Synovial fluid analysis for septic arthritis will demonstrate a significantly elevated white blood cell count typically greater than 50 000 cells with a predominance of neutrophils (greater than 50%). The synovial fluid will be cloudy and yellow in appearance. Admission for parenteral antibiotics and repeated needle aspiration, arthroscopy, or open surgical drainage is required.

The patient in this question is presenting with a history and exam that are consistent with acute-on-chronic osteoarthritis. Osteoarthritis is defined as joint destruction that generally involves the distal interphalangeal joints with polyarticular exacerbations, but patients may present with an acute monoarthritis typically in the knee. Effusions are usually small and difficult to aspirate. Any fluid that is aspirated is noninflammatory. Patients usually do not have other systemic symptoms. Radiographs demonstrate joint space narrowing due to destruction of articular cartilage. Treatment includes joint rest and nonsteroidal anti–inflammatory agents such as ibuprofen.

Opioid medications such as acetaminophen with hydrocodone (A) have been shown to decrease pain in patients with osteoarthritis, however, adverse effects, particularly in older patients, limit opioid use, and in the ongoing opioid epidemic these medications should not be used as first-line therapy. Colchicine (B) is an alternative first-line treatment agent for patients with knee pain and swelling due to gout, a crystal-induced synovitis. The patient in this question is not presenting with a classic gouty flair, as typically gout presents with knee pain, swelling, redness, and sometimes warmth. Additionally, osteoarthritis is not treated with colchicine, as it is not an analgesic medication. Systemic corticosteroids such as prednisone (D) are not indicated for osteoarthritis, but intra-articular corticosteroids such as triamcinolone have been shown to improve pain for months in such patients. The corticosteroid injections can be performed by the patient’s primary physician or an orthopedist.

Septic arthritis is a bacterial or fungal infection of a joint typically spread hematogenously unless there is direct bacterial contamination. The synovium is highly vascular and lacks a basement membrane making it susceptible to bacterial seeding. Certain conditions predispose individuals to septic arthritis including diabetes, sickle cell disease, immunocompromise, alcoholism or pre-existing joint disease like rheumatoid arthritis or gout. Fever is present in less than half of cases of septic arthritis so with clinical suspicion an arthrocentesis is indicated. The knee is the most common joint affected and patients have pain (especially on passive range of motion) and decreased range of motion often accompanied by warmth, erythema and fever. This patient may have an acute gouty flare, but the clinician must exclude an infection. On joint fluid analysis, the white blood cell count of a septic joint is typically > 50,000.

Indomethacin (B) is a non-steroidal anti-inflammatory agent commonly used in the treatment of acute gout. Gout is arthritis caused by deposition of monosodium urate monohydrate crystals in the joint space. Acute flares involve a monoarticular arthritis with a red, hot, swollen and tender joint. Acute episodes of gout result from overproduction or decreased secretion of uric acid. However, measurement of serum uric acid (C) does not correlate with the presence or absence of an acute flare. A radiograph of the knee (D) may show chronic degenerative changes associated with gout but will not help to differentiate gouty arthritis versus septic arthritis.

Septic Arthritis

• Patient will be complaining of fever, monoarticular pain with decreased ROM
• Labs will show WBC > 50,000 with > 75% PMNs
• Diagnosis is made by arthrocentesis
• Most commonly caused by:
  • Age < 35: N. gonorrhea, S. aureus overall
• Treatment is IV ABX, surgical washout

Allopurinol therapy should never be initiated until an acute attack has subsided. Allopurinol is a xanthine oxidase inhibitor that decreases uric acid production but also produces a more soluble metabolite. Allopurinol is therefore effective regardless of the cause of the hyperuricemia. Gout is caused by deposition of uric acid crystals in the synovium, bursae, tendon sheaths, skin, heart valves, and kidneys, which can lead to arthritis, tophi, renal stones, and gouty nephropathy. Typically, patients present with acute, exquisitely tender, monoarticular arthritis. The joint is usually warm and erythematous. The first metatarsophalangeal joint (MTP) joint is most commonly affected. Detecting negatively birefringent, needle-like crystals in the synovial fluid from an arthrocentesis confirms the diagnosis. First line treatment are NSAIDs. Indomethacin has traditionally been the NSAID of choice, but any NSAID can be used with similar efficacy.

Ethanol metabolism blocks renal excretion of uric acid which increases the risk for developing gouty arthritis. However, allopurinol is not contraindicated in individuals who consume ethanol (B). Hyperuricemia (C) is present (usually >8 mg/dL) in the gout patient, and when symptomatic, these patients should be treated. Colchicine (D) can be used in combination with allopurinol to help decrease the likelihood of a gouty flare while the uric acid level is decreasing after an acute attack has subsided. Colchicine decreases inflammation associated with lactic acid production and phagocytosis of urate; it terminates most gouty attacks within 6 to 12 hours but is limited by GI side effects.

Gout

• Patient will be a middle-aged man
• Complaining of acute onset of pain in the first MTP (Podagra)
• Labs will show needle-shaped crystal with negative birefringence
• Most commonly caused by uric acid crystals
• Treatment is:
  • Acute: NSAIDs, steroids, colchicine 
  • Chronic: allopurinol or colchicine
• Comments: Can be triggered by loop and thiazide diuretics

With pain along the proximal portion of her arch worse in the morning, plantar fasciitis is the most likely diagnosis. Morton neuroma is a forefoot pain. With a negative Tinel sign, tarsal tunnel syndrome is ruled out. Achilles tendonitis is a posterior heel pain.

Hypothenar Hammer Syndrome: Raynaud sign Hypothenar Hammer Syndrome does not have a specific diagnostic test affiliated with it. Diagnostic maneuvers include tenderness to palpation over the hypothenar area, which may indicate the presence of an ulnar artery aneurysm. The fingers or fingertips may be cold, pale, mottled, atrophic, or ulcerated, and a positive Allen test may suggest an ulnar artery pathology.

A Tinel sign is positive if light tapping over the median nerve at the wrist causes a tingling sensation distally along the median nerve and is useful in the diagnosis of Carpal Tunnel Syndrome.

The Finkelstein test requires that the patient flex the thumb into the palm and then grasp it with the other fingers of the hand. The patient then actively performs ulnar deviation of the wrist. Severe, sharp pain with this maneuver constitutes a positive test and is pathognomonic of de Quervain tenosynovitis.

Froment sign occurs when the adductor pollicis muscle, innervated by the ulnar nerve, is weak. This sign is elicited by having the patient tightly hold a piece of paper between the thumb and the radial side of the index finger while the examiner attempts to pull the paper from the patient. Flexion at the thumb interphalangeal joint (indicating weakness of the adductor pollicis muscle) results in a positive Froment sign. Comparison should be made with the patient’s other hand.

Although disseminated gonococcal disease must be considered, this patient has Reiter syndrome (reactive arthritis), also termed reactive arthritis. These patients are colloquially known to complain they “can’t pee, can’t see, can’t climb a tree.” Conjunctivitis and iritis can be a serious complication that must be actively ruled out.

An elevated hemiscrotum (elevated testicle) with transverse lie is suggestive of testicular torsion, resulting from twisting and foreshortening of the spermatic cord. A palpable bulge in the inguinal region may be present in the case of inguinal hernia, epididymal tenderness in epididymitis, and scrotal ecchymosis in genitourinary trauma.

A positive prehn sign (relief with lifting of the testicle), indicates epidydimitis. NEGATIVE prehn may suggest torsion (no relief).

This patient is presenting in severe sepsis and Fournier’s gangrene. Empiric antibiotics and medical resuscitation should be administered, but this patient requires emergent surgical debridement for definitive treatment. While hyperbaric oxygen has been used in the treatment of necrotizing fasciitis, it is an adjunctive therapy.

When a child presents with abdominal pain, nausea and vomiting, one must perform a testicular/scrotal exam to rule out acute scrotal or testicular pathologies. In this case, the presence of a swollen right testicle and scrotal pain but negative ultrasound findings is concerning for intermittent testicular torsion. It is important to remember that testicular torsion is a clinical diagnosis, requiring a high index of suspicion, even in the face of early, unremarkable ultrasound findings. Blue-dot sign is typically seen in torsion of the appendix testis. Pain alleviation with testicular elevation is seen in epididymitis. The treatment of testicular torsion starts with manual detorsion, followed by timely surgical detorsion and fixation.

The patient in this case has priapism. Given the history of sickle cell disease, and no preceding trauma, this is likely the ischemic, or low-flow type of priapism. All of the above treatment options are appropriate for low-flow priapism, with the exception of angiography with embolization, which is used for high-flow priapism. Other treatment options for low-flow priapism include intracavernosal aspiration and surgical shunt placement. Urology consultation should be obtained for low-flow priapism.

Testicular pain, swelling, and asymmetric hyperemia of epididymis on ultrasound are suggestive of epididymitis. Epididymitis is a clinical diagnosis, combined with ultrasound examination and urinalysis. The choice of antibiotics follows an arbitrary division at age 35. Younger than 35 years of age, patients are treated with ceftriaxone and azithromycin for presumed Chlamydia and Gonorrhea infection. After 35 years of age, patients are treated with fluoroquinolone for presumed E. coli infection. Analgesics and scrotal elevations should be recommended. Prehn’s sign is a relief of pain with scrotal elevation and is seen in epididymitis, as opposed to no changes in pain in testicular torsion. Emergent urology consultation is not required, but patient may follow up with urology as outpatient.

Amiodarone can cause a chemical epididymitis, which is characterized by testicular pain and swelling. This effect is more common with chronic (greater than 4 months) and high dose (more than 400 milligrams per day) amiodarone use. Amiodarone concentrates in the testicle where is causes lymphocytic infiltration and fibrosis. Unlike patients with infectious epididymitis, patients do not experience fever, pyuria, or leukocytosis.

This patient presents with phimosis and evidence of vascular compromise requiring performance of a dorsal slit procedure. Phimosis occurs when the foreskin of an uncircumcised penis becomes constricted preventing retraction of the prepuce from the glans. It results in urinary outlet obstruction, glans ischemia and infarction. Many cases are physiologic resulting from normal development. Patients typically present with an unretractable foreskin and symptoms consistent with urinary obstruction including decreased urinary stream. Management of phimosis can be difficult. Dilation of the prepuce can be performed using forceps but often does not result relief of phimosis. When there are signs of glans vascular compromise (i.e. discoloration) a dorsal split procedure should be performed. During this procedure, the foreskin is anesthetized and incised dorsally allowing for retraction.

The patient presents with balanitis, which results from inflammation of the glans penis or the glans and foreskin (balanoposthitis). The primary cause is infection, most commonly Candida. Treatment consists of  topical antifungal. Balanitis can also be caused by bacterial agents such as group A beta-hemolytic streptococci. Additionally, it may be secondary to irritation, trauma or contact dermatitis. Recurrent balanitis is seen in diabetics from C. albicans. Patients typically complain of pain, discharge, and itching. The glans may appear erythematous and tender to palpation. Systemic symptoms may be present but are unusual. Management of fungal balanitis includes topical antifungal agents such as clotrimazole, adequate hygiene and glycemic control. In patients with no history of diabetes who present with fungal balanitis, diabetes should be considered and a finger stick should be obtained.

Phimosis is the inability to retract foreskin over the glans penis. It is a complication seen in uncircumcised men. About 50% of boys typically are able to retract their foreskin by 1 year of age and 80% by age 3. Topical estrogen therapy has been reported as successful, but no randomized trials support its use. However, low-potency topical corticosteroid therapy combined with daily prepuce retraction appears effective for phimosis. If retraction of foreskin is unsuccessful, the patient will require circumcision.

Testicular torsion usually occurs over an arc of 540 to 720 degrees. Manual detorsion generally requires one to three turns in the medial to lateral direction (“opening a book”) to restore blood flow and relieve pain, and is successful in up to 70% of patients. It is best carried out with the patient supine in a frog leg position.

Although the patient’s examination is consistent with BPH (associated with increased rates in asymptomatic hematuria), he is also at risk for urologic malignancies and needs urgent referral to urology for further evaluation. His urinalysis and lack of symptoms rule out a urinary tract infection as a cause for the hematuria. If urolithiasis is suspected, a noncontrast CT scan should be ordered to confirm the diagnosis.

Acute tubular necrosis accounts for up to 85% of intrinsic renal failure in adults and might occur in the described patient due to the combined renal insults of ischemia secondary to shock and intravenous contrast. Acute interstitial nephritis is a far less common cause of intrinsic renal failure in adults and is usually caused by a drug hypersensitivity reaction. The patient described in this scenario is unlikely to have postrenal azotemia, which is due to obstruction, given the case details. Hemolytic uremic syndrome is classically a disease of children.

Diuresis in an already dehydrated and therefore pre-renal patient may lead to worsening renal function due to renal ischemia. A “trial of diuretics” is not generally advised and is not without risk to the patient. There is no compelling evidence that the combination of diuretics and dopamine helps to prevent progression to end-stage renal disease for oliguric acute renal failure patients. Therefore neither can be considered “routine” therapeutic interventions.

Peritonitis is a fairly common occurrence in patients maintained on CAPD. It is usually initially recognized when peritoneal fluid is noted to be cloudy at the time it is drained for a routine exchange. With prompt medical attention, including microbiologic evaluation of peritoneal fluid, patients can be treated with intraperitoneal antibiotics as outpatients after an initial intraperitoneal dose is given in the ED. The prognosis of uncomplicated peritonitis is generally excellent, and patients are typically asked to follow up in 2 days. Free air seen on abdominal plain film is most often due to air being introduced during a previous fluid exchange. CT scanning is not indicated unless there is severe abdominal pain and tenderness or other findings suggestive of perforation.

Vascular access infections are not uncommon in hemodialysis patients, and patients may present with fever alone, and no local or systemic findings. Although bacteremia is often found, endocarditis is unusual in the absence of prolonged or recurrent fever, or of the usual risk factors for infective endocarditis. The hemodialysis procedure itself rarely causes fever.

A 25-year-old man is brought from the hemodialysis unit because of hypotension that occurred during dialysis. His blood pressure is currently 94/60, pulse is 84, and he is afebrile. Physical examination is otherwise normal. An ECG is unchanged from a previous tracing. Which of the following is most accurate?

Infected obstructing urolithiasis is a urologic emergency. A critical aspect of treatment is prompt decompression of the renal collecting system by percutaneous nephrostomy catheter or retrograde ureteral stent placement. While adjunctive therapy with broad-spectrum intravenous antimicrobials is important, decompression remains the critical intervention. Foley catheter placement and monitoring of urinary output are important adjunctive interventions in patients with a variety of conditions such as sepsis.

Suprapubic catheters are prey to a number of complications including occlusion by debris or mucus. A clogged suprapubic catheter can be flushed with saline as a first attempt to unclog it. Suprapubic catheters should be changed every 4 to 6 weeks. The tract created by a suprapubic catheter may close rapidly if the tube is removed within the first month; thereafter, rapid tract closure is not a concern.

Commonly tested on boards. Calcium oxalate is the most common type of renal stone, accounting for more than 70% of all stones.

Do not miss an infected kidney stone. Calculous pyelonephritis is a urologic emergency and must be excluded in patients presenting with renal colic.

Perilunate dislocations, as well as perilunate fracture dislocations, are among the most devastating closed wrist injuries. They are often missed on initial evaluation and imaging. Most cases involve dorsal dislocation of the capitate and carpus relative to the lunate, while the lunate remains in near-normal alignment with the radius. Volar perilunate dislocations are possible but rare. An important pitfall, besides missing the injury altogether, is misdiagnosing the injury as a lunate dislocation, which can closely mimic a perilunate dislocation, especially on AP projection. The key to not confusing the two is the lateral projection. On a normal lateral wrist X-ray the capitate, lunate, and distal radius articulate with each other and lie in a straight vertical line, like an apple in a cup sitting on a saucer. The radius (the saucer) holds the lunate (the cup), and this cup contains the capitate (the apple). In a perilunate dislocation, the radiolunate articulation is maintained, but the capitate is not sitting within the distal articular “cup” of the lunate. In a lunate dislocation, on the other hand, the radiolunate articulation is disrupted and the lunate is tipped towards the palm, which is known as the “spilled teacup” sign. Although the diagnosis can be made on plain film, CT plays an important role in assessing for commonly associated occult fractures. A scaphoid fracture is found in approximately 60% of perilunate dislocations; this is then called a trans–scaphoid perilunate dislocation. Perilunate dislocations typically occur in young adults who suffered a high energy trauma, such as a motor vehicle collision, a fall from height, or an injury during a sporting event, resulting in loading of a hyperextended, ulnarly deviated hand, with the angle of this hyperextension determining the extent of injury. Patients may present with obvious marked swelling and deformity, or more subtly, complaining simply of a sprained wrist. A thorough trauma survey with assessment for associated injuries of the head, spine, thorax, and extremities is essential, due to the high energy mechanisms. Orthopedic or hand consultation is required. Like other dislocations, the perilunate dislocation is an emergency and should be reduced as soon as possible. If closed reduction cannot be achieved in the ED, the patient must be taken to the operating room for open reduction. Once the fracture is reduced, definitive treatment can be delayed until the patient’s condition allows additional intervention. Despite early and accurate treatment, stiffness, weakness, and degenerative osteoarthritis commonly occur in the long term. Latent carpal instability is one of the most feared complications and is especially difficult to prevent.

Bonus: what is the most feared complication of perilunate dislocation?  => Median nerve palsy

The coronal reconstruction from a cervical spine CT scan pictured above reveals a type III fracture of the second cervical vertebra. There are three common varieties of fracture of the second cervical vertebra involving the dens, or odontoid process, which articulates with the ring of the first cervical vertebra and which are most common seen in the elderly. The characteristic appearance of the fracture which involves the body of the second cervical vertebra is typical for type III fractures. Type II fractures present at the junction of the odontoid process and the vertebral body. Type I fractures involve the tip of the odontoid process.In neurologically intact patients, these fractures are typically initially treated non-operatively with a trial of cervical immobilization in a hard collar.

It is thought that odontoid fractures are more common in older individuals due to age-related bone loss coupled with the fact that there is disproportionate bone loss in the second cervical vertebra at the base of the odontoid process. Since patients who are 1 to 20 years of age (A), 21 to 40 years of age (B), and 41 to 65 years of age (C) are at lower risk of osteoporosis, they are at less risk for a type III odontoid fracture as compared individuals older than 65 years of age.

Nasal bone fractures account for almost half of all facial fracture injuries. Assaults and sports injuries cause the majority of these injuries. The nose is easily exposed to trauma as it is the most anterior and prominent feature of the face. The frontal sinus is protected by a thick cortical bone and is typically more resistant to fracture than other facial bones. Frontal sinus fractures occur only with high impact traumas such as motor vehicle collisions, assaults with weapons, and industrial accidents. Because of the high energy required to fracture the frontal sinus bone, it is rare to find an isolated fracture without other underlying intracranial pathology. Taking this information into consideration the facial bone LEAST likely to fracture is the frontal sinus bone and the facial bone MOST likely to fracture is the nasal bone.  

Mandible fractures are more common in higher impact injuries such as motor vehicle collisions, sports injuries and interpersonal violence. Most fractures occur at the angle of the mandible or the mandibular condyle. A decent blow to the face during a fight is enough to fracture the mandible making it more likely to break than the frontal bone; hence mandible is least likely and maxilla is most likely (B) is incorrect. Fractures of the maxilla are often the result of high energy blunt force from motor vehicle collisions and falls. Because of its relationship with the orbital bones, nasal cavity and oral cavity, maxilla fractures can be life threatening and disfiguring. Zygomatic fractures typically occur secondary to motor vehicle collisions. Due to the thickness of the bone, isolated zygomatic fractures are uncommon. Taken together this information means that the maxilla is LEAST likely and zygoma is MOST likely (C) is incorrect. Orbital fractures commonly occur in men in the third decade of life secondary to motor vehicle collisions or interpersonal violence. Orbital fractures typically do not occur in isolation as the orbits are set back in the facial structure. The weakest portions of the orbit, and therefore the most frequently fractured, include the orbital floor bones, the maxilla and the lamina papyracea. A direct blow to the eye frequently causes a blow out fracture of the orbital bones; however, this fracturing likely helps to prevent globe rupture. It is easier to fracture the orbital bones (D) than many other facial bones, but nasal fractures are still more likely than orbital fractures.

Important historical information when assessing a patient with a hyphema includes a family or personal history of sickle cell disease or trait, which contributes to a higher risk of complications due to sickled erythrocytes becoming stuck within the trabecular mesh through which fluids drain. This results in increasing intraocular pressure and related microvascular occlusions or retinal and ocular nerve ischemia. These patients require aggressive treatment. Also, a history of other bleeding disorders may indicate difficulty in controlling hemorrhage, as does use of anticoagulants, aspirin, other nonsteroidal anti-inflammatory agents, and alcohol. The time of injury is also important because the chance of rebleeding increases when the development of the hyphema occurred over 24 hours prior to evaluation. Rebleeds tend to occur from two to five days after the injury and put the patient at more risk of corneal staining, development of post-traumatic glaucoma, and delay in resolution of the hyphema.

Helmet use with injury (A) is incorrect. Helmet use may be relevant to other possible injuries, but not specifically to determining a patient’s risk of complications related to the hyphema. Loss of consciousness with injury (B) is incorrect. Loss of consciousness may be an indicator of other potential injuries and their acuities, but it does not directly relate to risk of hyphema complications. Use of eyeglasses or contact lenses at time of injury (D) is also incorrect. While this information may be useful in determining whether other ocular or periorbital injuries are likely, it does not directly relate to risk of complications from the hyphema.

Pediatric injuries involving the physis (growth plate) are characterized using the Salter-Harris classification. This classification describes the fracture line relative to the physis. Injuries of the physis may affect normal bone growth and development, so orthopedic intervention may be necessary depending on the severity of the fracture type. Salter-Harris type I fractures occur when the epiphysis slips off the metaphysis with no associated fracture fragment. Type I injuries rarely affect skeletal development. Salter-Harris type II injuries extend into the metaphysis and are the most common of the Salter-Harris injuries. Salter-Harris type III injuries extend into the epiphysis. Salter-Harris type IV injuries involve the metaphysis, the physis, and the epiphysis. Salter-Harris type V injuries result from axial loading mechanisms and crush the epiphysis. These may be radiographically silent but often impact normal bony development.

Fractures with dislocation (B) may not involve the growth plate and are not part of the Salter-Harris classification. Intra-articular compaction (C) is seen in Salter-Harris type V injuries. Metaphyseal extension (D) is seen in Salter-Harris type II injuries.

The patient presents with hemorrhagic shock and an “open-book” pelvic injury and should immediately have an external pelvic binder placed. Unstable pelvic injuries are typically caused by high-energy impact as seen in motor vehicle collisions. The exact fracture pattern depends on the type of injury. Anteroposterior (AP) compression forces causes disruption near the symphysis pubis and sacroiliac joint opening resulting in the “open-book” pelvic injury. This injury can be diagnosed on an AP pelvic X-ray if the diastasis of the pubic symphysis is >2.5 cm. The high-forces from the injuries cause shearing and tearing of blood vessels leading to hemorrhagic shock. Examination of the pelvis will reveal gross instability. “Rocking” of the pelvis is discouraged as this force may dislodge clots that have formed. Instead, the greater trochanters should be grasped with both hands and gently squeezed together. Any movement with this procedure indicates an unstable pelvic fracture. Once an unstable pelvic fracture is recognized, it should immediately be stabilized with either a properly applied sheet and towel clamps or a commercial pelvic binder. Patients who have immediate stabilization have been found to have lower transfusion requirements. Additionally, the AP injury pattern stands to benefit the most from external stabilization.

Angiographic embolization (A) and CT scan of the abdomen and pelvis (B) may be useful in diagnosis and management of pelvic fractures and hemorrhage into the pelvis but the patient should not be transferred until they are more stable. Diagnostic peritoneal lavage (C) plays a role in differentiating between abdominal and pelvic injuries in unstable patients but should be deferred until after external pelvic stabilization has been applied.

In order to fully understand the different syndromes of injuries to the spinal cord, it is imperative to understand the location of the tracts of the cord. The posterior columns carry tracts responsible for ipsilateral position and vibratory sensation. The lateral spinothalamic tract carries fibers for contralateral pain and temperature. The lateral corticospinal tract is responsible for ipsilateral motor function. Syndromes may be incomplete depending on how much of the cord is affected by the injury. In the anterior spinal cord syndrome, just the posterior columns are preserved and so patients lose all pain and temperature sensation as well as motor function. Most cases of anterior cord syndrome follow aortic surgery, but it has also been reported in the setting of hypotension, infection, vasospasm, or anterior spinal artery ischemia or infarct. In trauma, typically hyperflexion of the cervical spine causes the injury to the spinal cord.

Loss of all motor and sensory function (B) occurs with a complete transection of the spinal cord. Most commonly this occurs after a significant trauma. Isolated motor function loss (A) is not a classic syndrome and would result from a small area of injury on the cord just involving the corticospinal tract. Upper greater than lower motor weakness occurs (D) with a central cord syndrome. Sensory involvement is variable although burning dysesthesias in the upper extremities may occur. Most commonly the syndrome occurs after a fall or motor vehicle accident. Anterior cord syndrome may also be known as ventral cord syndrome.

This patient presents with a myocardial contusion and should have an echocardiogram performed to look for any cardiac damage. Myocardial contusion describes a nebulous condition. It can occur through several mechanisms including a direct blow to the chest and compressive force over a prolonged period of time. Histologically, the disorder has similar findings to those seen after acute myocardial infarction. The majority of contusions heal spontaneously but small pericardial effusions may develop. Delayed rupture after resorption of a hematoma is a feared but rare complication. Patients with myocardial contusion will present after trauma with external signs of trauma and typically have other concomitant thoracic lesions (pulmonary contusion, pneumothorax, hemothorax). Patients will typically have tachycardia (up to 70%). ECG may show dysrhythmia or ST changes but may also be normal. Although myocardial contusion has a very low rate of cardiac complications and it is not effective to admit all patients for workup, in the presence of ECG changes and elevated biomarkers, observation and echocardiography are a reasonable approach. Echocardiogram can be used to diagnose pericardial effusion, thrombi formation, and valvular disruption.

Radial nerve injury is the most common nerve injury seen after humeral shaft fractures. These fractures usually occur from a direct blow to the arm and can be seen in falls and motor vehicle collisions. Patients present with severe pain, arm swelling, and decreased range of motion. The arm can be shortened or rotated in a complete fracture depending on the location of the fracture. A complete neurovascular exam should be performed as with all fractures and dislocations. The radial nerve may be injured during humeral fracture in up to 20% of patients. The injury is usually a neuropraxia and resolves spontaneously in most patients. However, this recovery can take months. Humeral fractures rarely need specific reduction maneuvers for treatment. They should be placed in a sugar tong splint and placed in a sling. Gravity alone is typically successful in fracture reduction.

The anterior cruciate ligament (ACL) is the primary stabilizer of the knee. It resists anterior translation of the tibia on the femur and is the most frequently injured major ligament of the knee. A tear results from deceleration, hyperextension or marked internal rotation of the tibia on the femur. The majority of ACL tears occur during sporting activities such as skiing, football, soccer, and basketball. Clinically, there is usually rapid development of hemarthroses, causing significant swelling. Almost half of individuals report feeling or hearing a pop, which is the most reliable factor. There is usually instability of the knee or a “wobbly” feeling. The Lachman test is the most sensitive test (approximately 98% sensitivity) showing increased anterior tibial displacement and a soft end point. MRI is rarely necessary to make a diagnosis. Rest, ice, crutches, immobilization and NSAIDs are common initial treatment options. Some competitive young patients may choose reconstruction as the best possible chance to return to successful play.

CT scan of the abdomen has rapidly become the imaging modality of choice in diagnosing small bowel obstruction (SBO) as it is both highly sensitive and highly specific. Patients with SBO present with crampy abdominal pain with nausea, vomiting, constipation and abdominal distension. The pain can be generalized and often will come in waves. The rapidity of onset of symptoms depends on how proximal the obstruction is. More proximal obstructions will have a more rapid onset and peak of symptoms. CT scan of the abdomen and pelvis is the diagnostic modality of choice as it has a high sensitivity and specificity and can give additional information including location of obstruction, cause of obstruction and alternative diagnoses.

The acute onset of abdominal pain with minimal tenderness on examination in an elderly patient is concerning for mesenteric ischemia. Patients with ischemia may develop rectal bleeding either with frank blood or hemoccult positive stool. As ischemic time increases, the lactic acid may become elevated. CT angiography is the gold standard for diagnosis. This is a disease of the elderly with a median age of 70. The differential diagnosis of acute severe abdominal pain also includes rupture or leak of an abdominal aortic aneurysm and in this case a 2 cm aorta (normal) was identified. Mesenteric ischemia most commonly involves the small bowel and right colon. Due to the presence of a larger supply of collateral flow, the left colon is rarely involved. The mesenteric vessels include the celiac trunk, superior mesenteric artery and inferior mesenteric artery. The intestines require a constant supply of blood and typically receive 20% of the cardiac output. As a result, injury occurs rapidly in the setting of acute ischemia. More than 50% of cases of mesenteric ischemia result from arterial embolization, most commonly from a cardiac origin (atrial, ventricular or valvular on the left side). Patients with atrial fibrillation are at high risk of developing mesenteric ischemia. The superior mesenteric artery (SMA) is at highest risk because of its large caliber and small angle of takeoff from the aorta. Once the embolus lodges in the SMA the gut becomes ischemic. Jejunum is at highest risk because it receives little collateral flow from the celiac trunk and inferior mesenteric artery.

The presentation of multiple individuals with diarrhea following a shared meal is highly suspicious for foodborne illness. Foodborne pathogens cause illness through a variety of mechanisms. Pathogens like Staph aureus, Bacillus cereus, and Clostridium botulinum (bolulism) exert their toxic effects via a preformed toxin. Toxins present in the food prior to ingestion cause rapid onset of symptoms, typically within 1-6 hours. Bacillus cereus is associated with watery diarrhea and lower abdominal cramping. Foods associated with Bacillus cereus include meats, gravies, stews, and vanilla sauces. Another mechanism by which pathogens cause symptoms is via bacterial production of toxin after ingestion, such as seen withVibrio, Shigella, and Shiga-toxin-producing E. Coli. Some toxins alter fluid and electrolyte movements, causing large volumes of fluid that overwhelms the colon’s ability to absorb them, leading to diarrhea. Other toxins directly disrupt cell membranes leading to cell death. Many pathogens, including enteric viruses, Salmonella,Campylobacter and Shigella directly invade the intestinal epithelium, leading to fever, abdominal cramping, and diarrhea which is sometimes bloody. For acute nonbloody diarrhea without systemic signs of illness, serum and stools studies are not typically required, and patients can be managed supportively.

Epiploic appendagitis is caused by inflammation of the pouches of serosal fat that line the large intestine called epiploic appendages. This is a rare cause of abdominal pain, but its presentation mimics appendicitis and diverticulitis and therefore is sometimes found on CT scan performed in the evaluation of lower abdominal pain. More than half of cases occur in the rectosigmoid colon. Epiploic appendagitis is an inflammatory condition likely caused by autoinfarction of the appendages from torsion. Rarely, colonic bacteria may accumulate in the area causing abscess formation. Most patients present with pain localized to the region of appendagitis. Pain is classically dull and non-radiating. Patients may develop fever and show leukocytosis on laboratory analysis. The condition is most often self-limited and treatment is with pain medication like nonsteroidal anti-inflammatories (NSAIDs).

Sensitivity or the true positive rate measures the proportion of actual positives that are correctly identified as such. It is determined by dividing the number of true positives of the test by the number of true positives + false negatives. Tests with a high sensitivity are good for ruling out disease as the test has very few false negatives. A test with high sensitivity is advantageous as a screening tool as it misses very few people with the disease. The onset of abdominal pain before vomiting has been found to be as high as 100% sensitive in diagnosing acute appendicitis.

The X-ray demonstrates massive dilation of the colon through the cecum consistent with a large bowel obstruction. However, CT scan does not show any obstructing lesion and therefore this is a pseudo-obstruction, also known as Ogilvie’s syndrome. The exact mechanism of the development of pseudo-obstruction is unknown but suspected to result from malfunction of the autonomic control of the bowel. Patients often have multiple other co-morbid conditions and risk factors include nursing home residence, anticholinergic medication, severe electrolyte disturbance, narcotic exposure, or a history of spine or retroperitoneal trauma. This is a diagnosis of exclusion. Patients may first be treated with a rectal tube and sigmoidoscopy and managed conservatively in the hospital. Neostigmine may be used as a pharmacologic intervention as its an acetylcholinesterase inhibitor.

Ischemic colitis is a syndrome caused by inadequate blood flow through the mesenteric vessels, resulting in ischemia and eventual gangrene of the bowel wall. The most important finding is pain that is disproportionate to physical examination findings. The pain is diffuse, and the patient may report frank blood in the stool. These patients typically have a history of atherosclerotic disease at other sites, such as coronary artery disease or cerebrovascular disease. Other risk factors include advanced age and tobacco use. Classic angiography is the diagnostic imaging of choice, however it is invasive and therefore in current clinical practice, computed tomography angiography is ordered much more frequently than classic angiography. Bowel wall edema is the most common finding on imaging. All cases of ischemic colitis with signs of peritonitis or possible bowel infarction, generally warrant immediate surgical intervention for the resection of the ischemic or necrotic bowel. If the ischemia is caused by vasospasm then surgery is not indicated and medical management with anticoagulants and intra-arterial vasodilators is appropriate.

Acute appendicitis is the most common surgical emergency in pregnant women. The rate of acute appendicitis in pregnant patients is the same as seen in nonpregnant patients. Unfortunately, delays in diagnosis lead to an increased rate of perforation, increased morbidity and mortality. Physiologic changes during pregnancy make diagnosis difficult. As the uterus grows, the abdominal organs are more distant from the abdominal wall making it difficult to detect tenderness and peritoneal signs. Additionally, the location of the appendix later in pregnancy is variable as it can rest anywhere between the right lower quadrant to deep within the right upper quadrant. Ultrasound, CT scan and MRI are all viable diagnostic tests depending on availability. However, on occasion, patients will require exploratory laparoscopy.

Octreotide is a useful addition to endoscopic sclerotherapy and decreases rebleeding occurrences. Patients with documented esophageal varices and acute upper GI bleeding should be treated with an intravenous infusion of octreotide at 50 µg/hr for a minimum of 24 hours while being observed in the intensive care unit.

Hives and bronchospasm in this patient point to excessive histamine release. In the setting of diarrhea, histamine release would most likely result from a parasitic infection. This is not common; however, it should be considered in patients presenting with diarrhea and histamine-induced skin changes. Of the choices listed, Giardia lamblia is the only parasite.