Neuroendoscopic diagnosis of central nervous system histoplasmosis with basilar arachnoiditis

Histoplasmosis of the central nervous system (CNS) is seen in 10% to 20% of patients with disseminated histoplasmosis and/or in association with immunocompromised patients. Meningitis, arachnoiditis, and hydrocephalus are the most common clinical manifestations of CNS histoplasmosis. Patients with CNS histoplasmosis present similarly to other infectious etiologies, and confirmatory diagnosis is important in the management of these patients. However, diagnosis of CNS histoplasmosis can be difficult, and sometimes performing a parenchymal biopsy is necessary to confirm the diagnosis.

We describe the case of a 41-year-old man with HIV/AIDS who presented with the signs, symptoms, and radiologic evidence of basal meningitis and hydrocephalus. Cerebrospinal fluid (CSF) analysis from multiple lumbar punctures was negative. The patient underwent a neuroendoscopic procedure with diagnostic and therapeutic goals. Internal CSF diversion (endoscopic third ventriculostomy) and biopsy of the floor of the third ventricle and subarachnoid space were performed; surgical biopsies identified noncaseating granulomas, and ventricular CSF was positive for Histoplasmosis antibodies. The patient was treated with liposomal amphotericin B and itraconazole. The patient had resolution of his symptoms immediately after surgery, and 1-month follow-up computed tomography of the head demonstrated resolution of the hydrocephalus. At the last follow-up 12 months postoperatively, the patient has not required insertion of a ventriculoperitoneal shunt.

Clinicians should maintain a high index of suspicion for fungal basal meningitis in patients with AIDS and hydrocephalus. With nondiagnostic lumbar CSF sampling, neuroendoscopy can be considered as an alternative for diagnosis and treatment of basal meningitis and hydrocephalus.