Pneumocystis carinii pneumonia in patients without HIV infection

Pneumocystis carinii pneumonia (PCP) can occur in immunocompromised patients without HIV infection. Risk factors, clinical features, treatment outcomes, and factors related to mortality in these patients may be useful clinical data for physicians who care for these patients.

A retrospective study of PCP patients without HIV infection at Ramathibodi Hospital, from 1994 to 2001, was conducted. Only cases with microbiological and/or pathological proven were included.

There were 19 patients with 42.1 per cent males and a mean age of 44.6 years. All patients had underlying immunocompromised diseases. 94.7 per cent of the cases received immunosuppressive drugs. PCP occurred at a mean duration of 26.4 months after the diagnosis and treatment of underlying diseases. Common clinical presentations of PCP were progressive dyspnea, fever, and non-productive cough. All patients had abnormal chest radiography with a majority of bilateral interstitial infiltration (63.2%). Diagnosis of PCP was confirmed with microbiological examination from bronchoalveolar larvage (84.2%) and pathological diagnosis from transbronchial biopsy (15.8%). Almost all of the cases (94.7%) were treated with co-trimoxazole. Ten patients (52.6%) had concomitant bacterial pneumonia or fungal pneumonitis. Overall mortality rate was 36.8 per cent. Mortality was significantly higher in patients who needed mechanical ventilation (p = 0.006). There was a trend toward a higher mortality rate in patients with concomitant pulmonary diseases (p = 0.09).

PCP may complicate a variety of immunocompromised states especially autoimmune diseases and hematologic malignancy. Patients who receive corticosteroids and/or cytotoxic drugs should receive primary PCP prophylaxis. The mortality rate is high especially in severe cases that need mechanical ventilation. Intensive care and close monitoring are needed for these patients.