Can smoking marijuana cause meningitis?

February 2, 2018, 2:30 pm

Cryptococcus neoformans (


Cryptococcal meningitis in a daily cannabis smoker without evidence of immunodeficiency. Shapiro BB et al. BMJ Case Rep 2018 Jan 26 [Epub ahead of print]


Can smoking marijuana cause meningitis?

The question is not unreasonable. A wide range of pathogenic fungi — including Aspergillus and various Cryptococcus species — have been isolated from dispensary-grade medical marijuana samples. Concern that these pathogens could cause pneumonia or central nervous system infections has focussed on those with immunodeficiency, such as HIV and organ transplant patients.

This case report describes at 48-year-old California woman who presented to hospital with a “2-month history of progressive fatigue, dizziness, memory impairment, ataxia, and left-sided numbness and weakness.” She had a state medical marijuana card and reported smoking multiple “blunts” daily for the previous 35 years.

Tests were negative for HIV. Several days after admission, the patient developed lethargy and increasingly altered mental status. A lumbar puncture was performed, revealing increased white cell and protein with markedly low glucose (< 5 mg/dL.) CSF culture grew Cryptococcus neoformans.

The authors obtained nine samples of different strains of medical marijuana at the Bakersfield dispensary the patient frequented. All samples were contaminated by opportunistic fungi, including multiple Cryptococcal species and Aspergillus.

In the discussion section, the paper notes that both marijuana smoke and THC itself impair immune function in the lungs and CNS. However, I was not convinced by the authors’ suggestion that this patient was immunocompetent. The title states that she was “without evidence of immunodeficiency.” However, it seems to me the workup in that regard was inadequate. She was tested for HIV (negative) and to categorize lymphocyte count and subsets, but apparently not for T-celll function or any other immunological markers. Thus, its hard to know if the cryptococcal infection was caused by her marijuana use. The very fact that this is such an interesting case report demonstrates that the association, if causative, is exceedingly rare.

Related post:

Review: marijuana and health



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