Cryptococcal Meningitis Masquerading as Normal Pressure Hydrocephalus in an Immunocompetent Adult
Ashwath Ravisankar1, Varshini Thiruvadi2
1Neurology, 2Internal Medicine, University of Illinois College of Medicine Peoria
Objective:
To describe an atypical presentation of cryptococcal meningitis mimicking idiopathic normal pressure hydrocephalus (NPH) in an immunocompetent older adult and highlight diagnostic pitfalls.
Background:
Cryptococcal meningitis classically follows pulmonary infection and presents with signs of meningoencephalitis, particularly in immunocompromised hosts. Its occurrence in immunocompetent patients is rare, and initial presentations resembling NPH are exceedingly uncommon, with only a handful of cases reported. This diagnostic overlap can delay recognition and appropriate therapy.
Results:
An 82-year-old immunocompetent man presented with progressive gait instability. Imaging showed ventriculomegaly, and fluoroscopic lumbar puncture revealed normal opening pressure and significant improvement in gait after LP, leading to a diagnosis of NPH. A ventriculoperitoneal shunt was placed, resulting in transient symptom improvement. He was readmitted weeks later with recurrent gait disturbance, confusion, and fever, with imaging suggestive of aspiration pneumonia. Despite shunt adjustments and treatment for aspiration pneumonia, neurological symptoms worsened. MRI obtained then showed acute left cerebellar infarct. However, as mentation continued to worsen, repeat CSF analysis was done which revealed lymphocytic pleocytosis and positive cryptococcal antigen and CSF culture growing cryptococcus neoformans, confirming cryptococcal meningitis. He was treated with amphotericin B and flucytosine, followed by fluconazole. Progressively, he had worsening respiratory distress and Chest imaging revealed necrotizing cryptococcal pneumonia, suggesting a primary pulmonary source.
Conclusions:
Cryptococcal meningitis should be considered in older, immunocompetent adults presenting with the classic NPH triad, even in the absence of typical CSF findings. Up to 25–30% of patients may have normal initial CSF profiles, and misdiagnosis may delay appropriate antifungal therapy. Lumbar puncture should always be followed by CSF analysis even if there is a high clinical suspicion for NPH.
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