Week 7: Pneumonia, TB, pleural diseases, and PE

The most common infection seen in alcoholism is pneumonia. Associated risk factors for pneumonia include smoking, decreased ciliary function, decreased surfactant production, decreased cough reflex, malnutrition, and poor oral hygiene. Although alcoholic patients may contract a variety of bacterial pneumonias, Streptococcus pneumoniaeis still the most common organism.

This patient has a health-care associated pneumonia (HCAP) requiring IV antibiotics and admission. HCAP is defined as infection occurring within 90 days of a 2-day or longer hospitalization; in a nursing home or long-term care residence; within 30 days of receiving intravenous antibacterial therapy, chemotherapy, or wound care or after a hospital or hemodialysis clinic visit. HCAP requires IV broad spectrum antibiotics because it may involve both the typical pathogens involved in community-acquired pneumonia (CAP) (Mycoplasma pneumonia, Haemophilus influenzae,Streptococcus pneumoniae and Chlamydia pneumoniae) as well as more resistant organisms (Acinetobacter species, Pseudomonas species, Staphylococcus aureus (including MRSA) Enterobacter species, Escherichia coli, Proteus species, Klebsiella species etc.). Treatment should be as follows (one antibiotic from each category):

Most patients evaluated for tuberculosis present with reactivation of an old infection. When an immunocompetent person is exposed to tuberculosis, the immune system effectively gains control over the infection in the lung. It remains quiet and often never re-activates during a person’s lifetime. Most patients are asymptomatic during primary infection and only develop symptoms during a re-activation. Approximately 8-10% of persons who do not take chemoprophylaxis after a primary infection (typically identified through a positive skin PPD test) will develop active tuberculosis. Cough is the most common symptom of pulmonary tuberculosis. Additionally, patients may develop fever (more common in the afternoon or evening), night sweats and hemoptysis. Due to the effects of cytokines (particularly tumor necrosis factor alpha), patient often lose weight. The classic X-ray finding on chest radiograph is a cavitary lesion in the upper lobe of the lung. However, tuberculosis can cause any abnormality on the X-ray including infiltrate in any portion of the lung. Lymphadenopathy is commonly seen in the hilum on X-ray.

Patients with lung abscess classically present with several weeks of cough, fever, pleuritic chest pain, weight loss, and night sweats. There may be cough productive of putrid sputum. Because the progression of lung abscess is indolent, tachycardia, tachypnea, or fever may be absent. The chest radiograph often shows an area of dense consolidation with an air-fluid level inside a thick-walled cavitary lesion. Those who abuse alcohol or have other conditions associated with the potential for aspiration are at greatest risk for lung abscess development.

Corticosteroids are used as adjunct therapy in HIV-positive patients with severe PCP (now known as Pneumocystis jiroveci pneumonia), defined by a room air arterial oxygen partial pressure (PaO₂) of less than 70 mm Hg or analveolar-arterial oxygen gradient that exceeds 35 mm Hg. When administered, steroids should be given before trimethoprim/sulfamethoxazole or pentamidine because microbial degradation and clearance caused by antibiotics may trigger a severe inflammatory response. Corticosteroid therapy can blunt this inflammatory response, improve oxygenation, and reduce the incidence of respiratory failure.

This is an exudative pleural effusion as defined by Light’s criteria (see Box 77-3). A pH less than 7. 0 suggests emphysema or esophageal rupture. This patient is at risk for both; hence the need to assess esophageal integrity. A pH less than 7. 0 with glucose less than 50 mg/dL are indications for tube thoracostomy. Normal pleural fluid has a WBC count of less than 1000/mm3.

The sensitivity of a single scan is 95%. Thus, 5% are missed.

In moderate- to high-risk patients with an elevated D-dimer level, a single ultrasound examination may be insufficient. A repeated study in 2 to 7 days is often sufficient to confirm the diagnosis. The lack of pulmonary symptoms precludes the need for lung and embolus evaluation at this time. During pregnancy, there is a progressive rise in baseline D-dimer concentration; thus, a “normal” value is useful, but an elevated level is of no discriminatory value.

Whereas risk factors increase the chance for a disease, many patients without known risk factors are also at risk, and being “healthy” does not rule out the possibility of venous thromboembolism. Risk factors are best applied to population analysis and are of limited use in evaluating a single patient.

The patient has a PE and hypotension even after a 2L fluid bolus. The CT shows a large mainstem thrombus. Thrombolytic therapy is indicated in a patient with a confirmed PE and systolic BP <100 systolic with no contraindications to thrombolytic therapy. Thrombolytic therapy has been shown to improve the hemodynamic profile in patients with hemodynamic instability. Heparin should be held when thrombolytics are being infused. Embolectomy can be life saving in patients with hemodynamic instability. Depending on where you work this may be done by thoracic surgery or interventional cardiology. Given the patient is already hypotensive further risk stratification with formal echo and troponin is unnecessary. Bedside ultrasound may be performed but should not hold up therapeutic interventions.