Pulmonary Infections in Immunocompromised Patients

Immunocompromised patients with pneumonia can have infection with both common pulmonary pathogens and opportunistic pathogens. A basic microbiological workup should be performed in all immunocompromised patients who are hospitalized and considered for outpatients. The need for a more extensive and invasive workup (eg, bronchoscopy for bronchoalveolar lavage transbronchial lung biopsy) should be individualized, considering risk factors for opportunistic pathogens. As part of treating immunocompromised patients with pneumonia, it is important to evaluate whether any immunosuppressive medications can be discontinued or decreased to improve the patient’s level of immunity. Empiric therapy for opportunistic pathogens should be considered in patients who have risk factors for a particular pathogen and when delaying appropriate therapy would increase mortality risk.

Case 3. JR is a 45-year-old man with rheumatoid arthritis that was diagnosed 5 years earlier. He is currently taking long-term high-dose corticosteroids (prednisone, 20 mg daily) and the tumor necrosis factor (TNF)-alpha inhibitor infliximab. JR has had progressive shortness of breath for the past week with nonproductive cough, low-grade fever, and fatigue.

Vital signs include temperature of 100.9°F (38.3°C), heart rate of 110/min, respiratory rate of 24/min, blood pressure of 120/80 mm Hg, and oxygen saturation of 88% on room air. Physical examination reveals bilateral fine crackles on auscultation and mild synovitis of the joints due to rheumatoid arthritis. Laboratory testing shows a white blood cell count of 6,500/μL (6.5 × 10 ⁹/L), hemoglobin of 12 g/dL (120 g/L), and platelet count of 150,000/μL (150 × 10 ⁹/L). Arterial blood gas testing shows a pH of 7.45, partial pressure of carbon dioxide of 35 mm Hg, partial pressure of oxygen of 55 mm Hg, and bicarbonate of 24 mEq/L (24 mmol/L). Chest radiography demonstrates diffuse interstitial infiltrates that are more pronounced in the perihilar regions. Chest computed tomography (CT) demonstrates ground-glass opacities, predominantly in the upper lobes.