Cryptococcal Meningitis

Cryptococcal Meningitis is meningeal infection that commonly affects patients with HIV but can also occur in patients who are immunosuppressed by other means. Individuals who are not immunocompromised can also develop this infection. Cryptococcus neoformans is an encapsulated yeast that can precipitate the development of cryptococcosis. Identifying cryptococcal meningitis is important as individuals may be mistakenly diagnosed with dementia, cognitive impairment, or treated incorrectly for other infections (e.g. - urinary tract infections). Cryptococcal meningitis is thought to be under-diagnosed and under-treated due to lack of awareness among clinicians.

• The environmental reservoir of cryptococci (depending on the species) includes avian guano, decaying organic matter, soil, noneucalyptus tree species, soil, air, freshwater, and seawater.^[1]
• HIV-infected patients are at the greatest risk for developing a cryptococcal infection.
• The use of immunosuppressive agents, and older age (even in the immunocompetent) are also risk factors.

There have been multiple numerous reports where cryptococcal meningitis in older adults have been misdiagnosed as Alzheimer's dementia or vascular dementia.^[2] As a result, it is difficult to estimate the prevalence of cryptococcal meningitis as the cause of cognitive impairment because the work up for dementia traditionally does not include a lumbar puncture. The American Academy of Neurology (AAN) practice parameter for the evaluation of dementia states that a lumbar puncture should be performed when any of the following are present: metastatic cancer, suspicion of central nervous system (CNS) infection, positive serum syphilis serology, hydrocephalus, dementia in a person younger than 55 years, a rapidly progressive or unusual dementia, immunosuppression, and suspicion of CNS vasculitis.^[3]

Case reports have included the following:

• Cryptococcal Meningitis in a Patient With Cognitive Impairment and Giant Cell Arteritis Treated With Steroids: A Case Report
• Aharon-Peretz, J., Kliot, D., Finkelstein, R., Hayun, R. B., Yarnitsky, D., & Goldsher, D. (2004). Cryptococcal meningitis mimicking vascular dementia. Neurology, 62(11), 2135-2135.
• Ala, T. A., Doss, R. C., & Sullivan, C. J. (2004). Reversible dementia: a case of cryptococcal meningitis masquerading as Alzheimer's disease. Journal of Alzheimer's Disease, 6(5), 503-508.
• Rafael, H. (2005). Letter to the Editor: Secondary Alzheimer started by cryptococcal meningitis.
• Hoffmann, M., Muniz, J., Carroll, E., & De Villasante, J. (2009). Cryptococcal meningitis misdiagnosed as Alzheimer's disease: complete neurological and cognitive recovery with treatment. Journal of Alzheimer's Disease, 16(3), 517-520.
• Kumar, A., Gopinath, S., Dinesh, K., & Karim, S. (2011). Infectious psychosis: cryptococcal meningitis presenting as a neuropsychiatry disorder. Neurology India, 59(6), 909.
• Ikumi, K., Yokoi, K., & Ando, T. (2015). Cryptococcal meningoencephalitis presenting with treatable cognitive impairment and involuntary movement. Rinsho shinkeigaku= Clinical neurology, 56(1), 27-31.
• Prakash, P. Y., & Sugandhi, R. P. (2009). Neuropsychiatric manifestation of confusional psychosis due to Cryptococcus neoformans var. grubii in an apparently immunocompetent host: a case report. Cases Journal, 2(1), 1-3.

• The most common clinical presentation of cryptococcal meningitis includes subacute headache and confusion.
• The classic feature of “meningism,” including neck stiffness, actually occurs in less than 20% of patients
• Cryptococcal meningitis can also present in an indolent manner, and individuals may only report cognitive impairment without associated symptoms.
• Subacute meningitis is the most common presentation of cryptococcosis, and it may be steadily progressive for weeks, months, and sometimes years.

• Both CT and MRI should be ordered as part of the work up
• EEG may be ordered as well
• Lumbar punctures should be performed in individuals with metastatic cancer, suspicion of central nervous system (CNS) infection, positive serum syphilis serology, hydrocephalus, dementia younger than 55 years, a rapidly progressive or unusual dementia, immunosuppression, and/or a suspicion of CNS vasculitis.
  • Typical CSF features include a raised opening pressure (i.e. - elevated intracranial pressure), lymphocytic pleocytosis (increased white blood cells), and evidence of inflammation.
  • However, CSF may be normal in 10%–17% of patients!

• Flucytosine and amphotericin B liposomal are antifungal treatments used.