title: Atypical Pneumocystis carinii pneumonia: the potential hazards of empiric treatment.
abstract: Pneumocystis carinii pneumonia occurred in two patients with unusual clinical findings. In one case, P carinii infection was diagnosed for the first time in a patient with Crohn's disease. Due to the lack of typical features in both cases an empiric trial of antimicrobial therapy could have delayed diagnosis and initiation of specific treatment for P carinii. Contrariwise, without histologic confirmation, specific therapy for P carinii pneumonia might have been mistakenly discontinued in the second patient. Empiric therapy with trimethoprim-sulfamethoxazole may cause rapid disappearance of P carinii cysts from pulmonary tissues and cause subsequent biopsies to be falsely negative in patients who fail to respond to treatment.
mesh_terms: D000328:Adult; D003424:Crohn Disease / Q000150:complications; D004338:Drug Combinations / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008875:Middle Aged; D010996:Pleural Effusion / Q000000981:diagnostic imaging / Q000209:etiology; D011010:Pneumocystis / Q000302:isolation & purification; D011020:Pneumonia, Pneumocystis / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000188:drug therapy*; D011859:Radiography; D013420:Sulfamethoxazole / Q000627:therapeutic use*; D014295:Trimethoprim / Q000627:therapeutic use*; D015662:Trimethoprim, Sulfamethoxazole Drug Combination
chemical_list: D004338:Drug Combinations; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D014295:Trimethoprim; D013420:Sulfamethoxazole