Stimulant Abuse and Hyperthermia
In order to operate properly, the human body must stay within a relatively narrow temperature range. Precise limits of this range vary from person to person; however, the vast majority of adults maintain a central or core body temperature of roughly 98˚ to 100˚F. The master guide for the maintenance of internal temperature is located in a brain structure called the hypothalamus. When temperatures rise too high, this structure sends signals to the body that trigger sweating and a widening (dilation) of blood vessels throughout the body. Sweating creates a cooling effect by triggering moisture evaporation; blood vessel dilation encourages proper evaporation by increasing blood flow and channeling heat.
Body hyperthermia officially sets in when core temperatures rise above 101.3˚F. In addition to drug use, potential causes of this level of temperature elevation include the effects of an unusually humid environment, abnormally low sweat production, excessive participation in exercise or other forms of physical exertion, and medical conditions such as thyroid gland malfunction, a hemorrhage inside the hypothalamus, an alcohol withdrawal complication called delirium tremens, and a rare, hereditary form of body temperature dysfunction called malignant hyperthermia.
Methamphetamine use/abuse can trigger hyperthermic conditions in both the body and brain, according to a study published in 2003 in the Society for Neuroscience's Journal of Neuroscience. These temperature elevations occur even when small doses of the drug are used, and grow worse as the level of methamphetamine intake increases. As a rule, meth-related hyperthermia produces higher temperature spikes in the brain than it produces in the body. Still, elevations in both areas are significant, and people who take excessive doses of the drug may experience extreme, life threatening increases in brain and/or body temperature of roughly 6˚ to 7˚F. In some cases, these increases may remain in effect for as long as three to five hours. People who use methamphetamine in active social situations commonly develop greater degrees of brain and body hyperthermia than people who use the drug by themselves or in more sedate social settings.
Cocaine-related hyperthermia is usually a symptom of a cocaine overdose. It occurs when excessive levels of the drug overstimulate the central nervous system, produce unusually high levels of activity in the body's major muscles, and also abnormally constrict (narrow) the body's blood vessels. Inside muscle tissue, cocaine-related temperature increases can trigger the onset of rhabdomyolysis, which occurs when individual muscle cells break down and release a pigment called myoglobin into the bloodstream. Molecules of this pigment travel to the kidneys, where they break apart and clog structures in the kidneys that normally filter waste and help maintain the body's fluid levels. In turn, obstruction of these structures can trigger potentially fatal kidney failure.
MDMA raises normal body temperature by narrowing the blood vessels and decreasing the effectiveness of evaporative body cooling. In turn, rising body temperatures in an MDMA user/abuser can trigger dehydration. In many cases, the mind-altering effects of the drug worsen the potential for dehydration by diverting attention away from the presence of thirst. In addition, many people use MDMA in hot, physically active social environments that contribute even further to poor body cooling and dehydration. To make things worse, some people unintentionally use impure forms of MDMA that contain dextromethorphan or other hyperthermia-inducing additives.
In addition to rhabdomyolysis and related cases of kidney failure, MDMA-related hyperthermia can lead to serious complications that include hypotension (abnormally low blood pressure), tachycardia (an abnormally rapid heartbeat), liver failure, a blood clot and bleeding disorder called disseminated intravascular coagulation, and complete collapse of normal function in the heart and blood vessels (cardiovascular system). As is true with the conditions associated with methamphetamine- and cocaine-related hyperthermia, these complications sometimes produce fatal outcomes in MDMA users.