We’re aware of the risks of energy drinks, including high blood pressure, but a new report shows the caffeine-rich beverages can be downright dangerous. A case study from the University of Alabama at Birmingham (UAB) has revealed the first incident of a patient experiencing brain bleeding as a direct result of consuming an energy drink.

The patient, a 57-year-old man who survived, developed an intracranial hemorrhage, or bleeding in the brain, within 15 minutes of drinking an energy drink. What’s more, according to the patient, this was the first time he had ever consumed this particular brand of energy drink, which was not named. The patient described symptoms of tingling and numbness in the right arm and leg, and trouble walking. Later, a CT scan revealed a small hemorrhage near the left thalamus, according to a UAB statement.

This particular drink contains several supplements for which we have little understanding of their potential interactions with each other or with caffeine," Anand Venkatraman, M.D., a fourth-year resident in the Department of Neurology at UAB and the lead author of the study, explained in a recent statement. "One is structurally similar to amphetamines, and several are known to stimulate the sympathetic nervous system."

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According to the report, the combination of these ingredients caused the patient’s body to go into “flight or fight” mode. This can be particularly dangerous for patients who already have weakened blood vessels, as it can raise blood pressure, increasing risk of rupture or hemorrhaging.

Venkatraman pointed out that it’s not just the ingredients in energy drinks that make them so dangerous, it’s also the serving size. Although most cans of energy drinks specify they are two serving sizes, the patient, like many other consumers, drank the entire can in one sitting.

Source: Venkatraman A, Khwaja A, Shapshak. Hemorrhagic stroke after consumption of an energy drink. American Journal of Emergency Medicine. 2016

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