Three adolescent cases of ischemic stroke involving the posterior fossa circulation and cerebellum occurred within days after the illicit use of marijuana and presented over a span of 5 years at St Louis University School of Medicine, MO. Headache, fluctuating consciousness or lethargy, visual disturbance, variable dysphagia/dysarthria, and ataxia were the common presenting manifestations. Cerebellar infarction was confirmed by biopsy (1 case) or necropsy (2 cases). Cerebellar and cerebral edema without brainstem compromise or herniation led to death in the 2 fatal cases. 
COMMENT. Marijuana use may cause systemic hypotension and vasospasm, leading to CNS ischemia and infarction. The cerebellum is considered more susceptible because it lacks collateral circulation. Early diagnosis of marijuana-induced stroke is necessary to permit prompt neurosurgical relief of cerebellar edema and brainstem compression.