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Cannabis and Reversible Cerebral Vasoconstriction Syndrome

RCVS is characterized by the presence of severe headaches with or without neurological complaints. Over the years investigators have associated various events with the onset of RCVS, and one major precipitating factor that is consistently reported is an association with exposure to various drugs.

Ducros A, Boukobza M, Porcher R, et al: The clinical and radiological spectrum of reversible cerebral vasoconstriction syndrome. A prospective series of 67 patients. Brain 2007;130:3091-3101.

Yau WY, Chu E, Lai N: Cannabis, serotonergic drug use and stroke in a 50-year-old woman. Intern Med J 2015; 45:1312-1313.

A collection of clinical findings along with signs and symptoms is commonly called a syndrome. One particular group of disorders that physicians have combined into a syndrome is named Reversible Cerebral Vasoconstriction Syndrome (RCVS).

RCVS is a rare and poorly understood disorder.  RCVS is characterized by the presence of severe headaches with or without neurological complaints or abnormal findings on examination AND a particular visible pattern when dye is injected into the arteries supplying the brain (cerebral angiography) that makes them appear as a “string and beads”. The string and beads represents narrowing and can be associated with decreased blood flow to the brain, This abnormal pattern seen on cerebral angiography usually normalizes over weeks to a few months.  Some patients experience strokes and permanent disability. Other patients may experience neurological deficits (for example, weakness, visual changes, or lethargy) that resolve over several days to months. Others have no complaints except for the headaches.

Over the years investigators have associated various events with the onset of RCVS, and one major precipitating factor that is consistently reported is an association with exposure to various drugs. Commonly reported drugs include marijuana, cocaine, amphetamines, some antidepressants, some decongestants, and other medications.  Among these, one of the most commonly reported precipitating drugs has been marijuana (Ducros 2007). Well-designed epidemiologic studies have not allowed for a definite conclusion that marijuana causes RCVS, but marijuana appears frequently as a proposed precipitating event or cause in cases that are described in the medical literature. Exposure to more than one precipitating drug is common. Of note, pregnancy and a history of migraine headaches are also common findings in patients with RCVS.

Thus, it is not completely surprising that another report has appeared in the medical literature linking a sudden increase in cannabis use with RCVS.  Dr. Yau and colleagues (2015) described a 50-year-old woman who experienced a severe stroke as a complication of RCVS. The woman was taking a medication to treat migraine headaches (a triptan), an antidepressant, and pain medication, and had been experiencing severe headaches for 2 weeks prior to presentation for hospitalization. She was drowsy, disoriented, blind, and weak or partially paralyzed on the left side of her body. Imaging studies showed multiple strokes in the brain, and MRA (a form of angiography) showed the typical pattern of a beaded, narrowed appearance. She had been a chronic user of marijuana but recently had increased her use from two joints every two weeks to 8 joints per day. Although narrowing of her cerebral arteries to the brain resolved over a few months, her brain damage remained and she did not recover from her deficits.

Given the severity of RCVS, it is important as a precautionary measure to keep in mind the possibility that marijuana exposure by itself or in combination with other drugs has been commonly reported to be a suspected precipitating cause. Regular users of medical marijuana should be aware of this syndrome and should seek medical care for severe and prolonged headaches. This is especially true if any weakness, loss of sensation or balance, change in vision, or change in level of consciousness occurs.