Disseminated Nocardiosis in Idiopathic CD4 Lymphocytopenia: A Rare Case and Literature Review.

Nocardiosis typically affects immunocompromised patients; however, the clinical characteristics of idiopathic CD4 lymphocytopenia (ICL) remain poorly understood. A 64-year-old patient was diagnosed with ICL following disseminated nocardiosis, including bacteremia, pneumonia, knee arthritis, and brain abscess. The patient underwent trimethoprim-sulfamethoxazole therapy with frequent dose adjustments based on the renal function, ranging from 2 to 12 single-strength tablets daily over 5 months of hospitalization. While he had a 1-year uneventful course of lifelong prophylaxis, he experienced prolonged recovery in physical activity. A literature review highlighted the life-threatening nature of nocardiosis in ICL, underscoring the importance of a timely diagnosis and tailored management strategies.