Pneumocystis jirovecii: A Fresh Look

Pneumocystis pneumonia (PCP) cases have become commonplace due to both HIV/AIDS and an increase in the therapeutically immunosuppressed population. Pneumocystis species are mammalian host specific, and rather than an environmental reservoir, it is now believed that it is children with asymptomatic infection who harbor and transmit the disease. PCP has an insidious onset, usually presenting with dry cough, fever, and dyspnea. On examination, patients will mostly have clear chests, in stark comparison with their breathlessness and bilateral infiltrates on chest x-ray. Diagnosis can be a challenge and a high level of suspicion is a good approach in at-risk patients. Patients who require mechanical ventilation have poor outcomes. HIV-uninfected patients often have worse outcomes, due to the frequent delay in diagnosis and the more extensive inflammatory response to the organism. These patients need to be treated empirically and without delay. The diagnosis can be confirmed on induced sputum or bronchial lavage specimens using immunofluoresence microscopy or polymerase chain reaction. Although not a confirmatory test, the serum biomarker (1-3) β-D-glucan, a fungal wall marker, has excellent sensitivity and specificity, enough to allow one to make clinical decisions in patients who find it difficult to give sputum. High-dose co-trimoxazole is the treatment of choice, with adjunctive prednisone in moderate to severe patients. It has recently been found that Pneumocystis plays a rol...
Source: Clinical Pulmonary Medicine - Category: Respiratory Medicine Tags: Topics in Pulmonary Medicine Source Type: research