Disseminated histoplasmosis and resistant tuberculosis in a patient with AIDS: A case report

Histoplasmosis is a systemic mycosis with a wide global distribution, being more prevalent and endemic in the American Continent. Its progressive disseminated form primarily affects immunosuppressed individuals and plays a significant role as an AIDS-defining illness. The challenging aspect of differential diagnosis with tuberculosis lies in the clinical, radiological, and laboratory similarities between these two conditions, making the spectrum of co-infection even more complex. In this clinical study, we present the case of a 22-year-old Venezuelan patient with no prior comorbidities who was admitted with symptoms of diarrhea, fever, weight loss, and persistent cough over a 30-day period. Initially, he was diagnosed with acquired immunodeficiency syndrome (AIDS) and subsequently with pulmonary tuberculosis. However, due to the persistence of symptoms, the delayed diagnosis of disseminated histoplasmosis (DH) was also established through blood culture. Additionally, the patient exhibited resistance to rifampicin, a condition not previously documented in the literature. After treatment with amphotericin B, adjustment of the tuberculosis therapy, and initiation of antiretroviral therapy, the patient experienced a significant clinical improvement and currently remains asymptomatic. This case underscores the importance of raising clinical suspicion for disseminated histoplasmosis (DH) in HIV-infected patients and implementing enhanced diagnostic strategies, especially in regions with limited access to healthcare services and complementary examinations. • A case reporting a patient with tuberculosis monoresistant to rifampicin and disseminated histoplasmosis had not been reported in the literature. • The case reinforces the importance of early diagnosis to avoid complications in immunocompromised patients. • Disseminated histoplasmosis can be a severe opportunistic infection in AIDS patients, often masked by tuberculosis. • The report underscores the clinical and laboratory challenges in managing tropical coinfections, further emphasizing that disseminated histoplasmosis is underdiagnosed in endemic regions. • The high viral load and severe immunosuppression were factors contributing to the dissemination of histoplasmosis.