Pneumocystis jirovecii pneumonia in a patient with Mycobacterium intracellulare pulmonary disease: a case report.

This report details the case of a 77-year-old female with Mycobacterium intracellulare pulmonary disease and history of bladder tumor surgery. The patient initially presented to our hospital with a one-day history of fever. After receiving antibiotic and anti-nontuberculous mycobacterial therapy for three days, the patient remained febrile. The patient's white blood cell and neutrophil counts were within normal range, while the lymphocyte count was decreased. Chest computed tomography (CT) revealed diffuse ground-glass opacities in the lungs. Further investigations demonstrated a significantly reduced CD4 + T-lymphocyte count. Mycobacterium intracellulare and Pneumocystis jirovecii (PJ) were identified in the bronchoalveolar lavage fluid (BALF) specimen. The patient was treated with oral trimethoprim-sulfamethoxazole (TMP-SMZ) and intravenous caspofungin. Following treatment, the patient's symptoms improved, and she was discharged. This study reports the first documented case of rare Pneumocystis jirovecii pneumonia (PJP) complicating nontuberculous mycobacterial lung disease. It underscores the importance of monitoring immune function and facilitating the early recognition of secondary infections in such patients.