Central nervous system histoplasmosis, a neurologic challenge: Report of two cases

Introduction: Histoplasmosis in the central nervous system is a fungal infection that affects 5% to 25% of patients with disseminated disease, being more common in immunocompromised patients. Clinical cases: We examined two different cases: Case 1. A 62-year-old male presented with abdominal pain and weight loss. Histoplasma capsulatum was confirmed by colonic biopsy. He later presented convulsions and medullary syndrome with multiple supratentorial and infratentorial abscesses. CD4+ low was found; desnutrition and alcohol intake were the only explanations, as HIV tests were negative. The selected therapeutic scheme was amphotericin induction plus itraconazole for one year. Follow-up showed clinical improvement. Case 2: A 51-year-old male presented with a 7-month clinical picture of weight loss, fever, dyspnea, and focal epilepsy. He had a recent HIV-positive diagnosis. Cerebrospinal fluid revealed hypoglycorrhachia and elevated protein levels, while brain resonance showed pachymeningeal enhancement. Histoplasmosis was confirmed by bone marrow biopsy, and other causes of pachymeningitis were ruled out. Treatment with amphotericin was initiated, leading to clinical improvement. Discussion: Histoplasmosis typically presents as chronic basal meningitis, while abscesses, pachymeningitis, or spinal involvement are infrequent. Altered consciousness and headache are the main symptoms. The diagnosis is delayed in 60% of cases. Cerebrospinal fluid (CSF) findings include hyperproteinorrachia (77%), hypoglycorrhachia (53%), and lymphocytic pleocytosis (50%). Although culture and antigen studies are useful, they have limited performance; therefore, imaging and histopathological studies are fundamental. Treatment with amphotericin and itraconazole is necessary and reduces mortality. Conclusion: Central nervous system infection by Histoplasma is an important challenge due to its variable clinical presentation and the complexity of diagnosis. Evidence remains limited; our cases are atypical and constitute the fourth and fifth cases reported in Colombia.