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February 10, 1997

Pneumocystis carinii Pneumonia Masquerading as Tuberculosis

Author Affiliations

From the Division of Infectious Diseases, Department of Medicine, University of Southern California School of Medicine, and the Los Angeles County—University of Southern California Medical Center, Los Angeles, Calif.

Arch Intern Med. 1997;157(3):351-355. doi:10.1001/archinte.1997.00440240117017

Recent laboratory studies indicate that genetic diversity exists in human strains of Pneumocystis carinii. Structural and functional variability in infecting strains could result in differences in host-parasite interactions and the natural history of P carinii pneumonia. We report 5 unusual cases in which the clinical presentation mimicked tuberculosis. All patients were cared for at a university-based public hospital clinic in Los Angeles, Calif, during a 2-year period. These patients were chronically ill, had lost weight, and each had cavities or cystic spaces as the primary radiographic findings. None were receiving aerosol pentamidine and only one had a history of smoking. Four patients were initially treated for tuberculosis and the fifth for disseminated Mycobacterium avium complex. Pneumocystis carinii was the only pathogen identified in each case. The unusual clinical presentations delayed the diagnosis of P carinii in all 5 cases. Practitioners must be aware of the variable presentations of P carinii pneumonia.

Arch Intern Med. 1997;157:351-355