Cryptococcal Meningitis

Cryptococcal meningitis is a life-threatening opportunistic infection predominantly associated with HIV/AIDS, accounting for over 100,000 deaths annually worldwide. However, it also affects individuals with other forms of immunosuppression, including those undergoing immunosuppressive therapy, organ transplant recipients, patients with innate immunodeficiencies, and individuals with hematological disorders. The infection is caused mainly by Cryptococcus neoformans and Cryptococcus gattii, encapsulated yeasts that show a strong neurotropism, facilitating their invasion of the central nervous system (CNS).

Inhalation of Cryptococcus spores initiates infection, leading to pulmonary colonization and hematogenous dissemination, particularly to the CNS. The pathogen’s polysaccharide capsule inhibits phagocytosis, while enzymes such as urease and metalloproteinases contribute to increased blood-brain barrier permeability. Immunological responses include antibody-dependent cellular cytotoxicity, natural killer cell activity, and T-cell–mediated immunity although these defenses are often insufficient in immunocompromised hosts.

Clinically, cryptococcal meningitis presents as a subacute meningoencephalitis, with symptoms such as headache, altered mental status, photophobia, and cranial neuropathies. HIV-positive patients often show an attenuated inflammatory response, resulting in subtle or atypical presentations. Diagnosis hinges on cerebrospinal fluid (CSF) analysis, including cryptococcal antigen testing, India ink staining, and culture. Elevated CSF opening pressure is a critical prognostic marker, necessitating frequent monitoring.

Treatment strategies involve a three-phase antifungal regimen: induction with amphotericin B combined with flucytosine, consolidation with fluconazole, and maintenance therapy to prevent relapse. Resource-limited settings often modify this approach due to the unavailability of flucytosine. Interprofessional collaboration among infectious disease specialists, neurologists, pharmacists, and radiologists is crucial for optimizing patient outcomes, ensuring prompt diagnosis, managing complications such as elevated intracranial pressure, and providing long-term follow-up to mitigate recurrence and neurological sequelae.