Cocaine Use and Ischemic Stroke
Ischemic stroke is a type of stroke that occurs when something blocks the flow of blood in a blood vessel leading to the brain. It differs from another form of stroke, called hemorrhagic stroke, which occurs when one of the brain’s blood vessels weakens and breaks open. More than 80 percent of all strokes are ischemic in nature. Cocaine users can develop an ischemic stroke through several different mechanisms that don’t typically lead to stroke in the general population. In addition, fatal ischemic strokes in cocaine users generally appear at an earlier age than strokes in the overall population.
Ischemic Stroke Basics
The brain sustains its normal function by taking in a constant stream of oxygen-rich blood from its supply of arteries. If this flow of blood ceases for even short periods of time, the cells in any affected area of the brain will die prematurely and trigger the onset of some form of brain damage. Whatever the underlying nature of the blood flow disruption, doctors refer to this set of circumstances as a stroke.
As noted previously, an ischemic stroke involves some sort of blockage in a brain artery. In the general population, a blockage in one of these arteries is typically the result of cholesterol-based fatty deposits that accumulate over time on the interior artery walls; doctors call this buildup process atherosclerosis or arteriosclerosis. In some cases, the accumulation of fatty deposits helps form an artery-blocking blood clot directly within the brain by acting as an anchoring point for the abnormal clumping of blood components called platelets; this is known as a cerebral thrombosis. In other cases, clots form in other parts of the upper body’s circulatory system, break loose, and travel through the bloodstream until they lodge in the brain and block normal blood flow; this is known as a cerebral embolism. Although ischemic strokes are far more common than hemorrhagic strokes, hemorrhagic strokes have a greater likelihood of killing affected individuals.
Cocaine’s Blood Vessel-Related Effects
Many of the effects of cocaine come from the drug’s ability to increase the level of activity in a part of the nervous system called the sympathetic nervous system, which is an involuntary network that connects to blood vessels throughout the body, as well as to the heart, lungs, kidneys, digestive system, eyes and sweat glands. This system operates all of the time in order to help maintain a stable internal environment. However, in moments of danger or extraordinary stress, it kicks into a higher gear and produces the “fight-or-flight” response, which prepares the body for various sorts of rapid action. In terms of the potential for development of ischemic stroke, cocaine’s most prominent effects are on the blood vessels, where it produces a narrowing called vasoconstriction, which increases system-wide blood pressure and promotes certain conditions that increase overall stroke risks.
Mechanisms of Cocaine-Related Ischemic Stroke
An ischemic stroke in cocaine users can result from a cerebral thrombosis or a cerebral embolism, just as in people who don’t use cocaine. However, according to a study published in 2011 in the National Stroke Association’s Journal of Stroke and Cerebrovascular Diseases, cocaine users also have ischemic stroke risks that stem from problems not usually found in non-cocaine users. These problems include unusual surges of high blood pressure in the brain’s arteries, a cocaine-related inflammation of the brain’s arteries known as drug-induced arteritis, and a syndrome called reversible cerebral vasospasm, which produces unpredictable contractions (spasms) in the blood vessel walls that can seriously restrict normal blood flow. Compared to people who don’t use cocaine, cocaine users also have a greater tendency to develop ischemic stroke as a secondary effect of arrhythmia, a heartbeat irregularity that can increase the chances for a stroke-producing cerebral embolism.
Cocaine users and non-users have roughly equal chances of developing an ischemic stroke as a consequence of baseline high blood pressure or excessive levels of LDL cholesterol in the bloodstream, the authors of the study in the Journal of Stroke and Cerebrovascular Diseases explain. However, for reasons that are not entirely clear, cocaine users typically receive the medications required to combat these problems significantly less often than non-cocaine users. Ischemic stroke kills cocaine users and non-users at roughly equal rates. However, the average cocaine user who dies from an ischemic stroke has a lifespan about seven years shorter than the average non-user who dies from an ischemic stroke.