Cryptococcal Meningitis in an Immunocompetent Patient With an Initially False-Negative Cerebrospinal Fluid Analysis: A Case Report

TL;DR

A case report shows that cryptococcal meningitis can affect immunocompetent individuals and highlights the importance of thorough testing for accurate diagnosis.

Contribution

Demonstrates the diagnostic challenges and successful treatment of cryptococcal meningitis in an immunocompetent patient.

Findings

Cryptococcal meningitis was confirmed in an immunocompetent patient after initial tests were negative.

Serial CSF sampling and molecular diagnostics were crucial for diagnosis.

The patient fully recovered after appropriate antifungal treatment.

Abstract

Cryptococcal meningitis (CM) is traditionally associated with immunocompromised states, such as HIV/AIDS. However, its presentation in immunocompetent hosts is increasingly recognized and frequently poses a diagnostic dilemma. A 56-year-old immunocompetent male presented with obstructive hydrocephalus following a month of worsening headaches. Initial cerebrospinal fluid (CSF) analysis, including India ink, cryptococcal antigen, and cultures obtained during ventriculoperitoneal shunt placement, was unremarkable. Subsequent brain MRI demonstrated evolving leptomeningeal enhancement and small cerebellar nodules. Due to clinical overlap, the patient was empirically treated for tuberculosis but developed an adverse cutaneous reaction. Driven by worsening imaging findings, repeat CSF studies were performed; fungal culture and PCR eventually confirmed Cryptococcus neoformans. The patient was treated with induction amphotericin B and flucytosine, followed by maintenance fluconazole, resulting in a full clinical and radiological recovery. This case emphasizes that CM must remain a differential diagnosis in subacute meningoencephalitis or unexplained hydrocephalus, regardless of immune status. High clinical suspicion warrants serial CSF sampling and molecular diagnostics to prevent delayed treatment of this potentially fatal infection.

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