Persistence of Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome. Evaluation of therapy by follow-up transbronchial lung biopsy.

The effectiveness of therapy with trimethoprim-sulfamethoxazole and/or pentamidine has not been fully evaluated in AIDS patients with Pneumocystis carinii pneumonia (PCP). Since recurrence of PCP is common, follow-up lung biopsy (15 transbronchial, one open) was performed as part of the clinical evaluation of 16 episodes of PCP. All patients had shown evidence of clinical improvement during treatment and had received a mean duration of therapy of 17.6 days. In six of 16 episodes (38 percent), however, a repeat biopsy remained positive for PCP an average of 25.2 days after initial diagnosis. Retrospective comparison of standard clinical parameters (fever response, arterial blood gas results, roentgenographic characteristics) could not adequately distinguish episodes with positive follow-up biopsies from those with negative biopsies. Persistence of PCP after conventional treatment may be an important factor in recurrences of this infection in AIDS patients.