Methamphetamine (meth, crystal meth) is an illegal street drug that, in many respects, roughly approximates the effects of legal drugs called amphetamines. People who use/abuse methamphetamine have significantly increased risks for the onset of kidney failure. In many cases, the events that lead to this failure begin when meth use and its side effects elevate normal body temperature to dangerous levels. In turn, this elevation can lead to the onset of a form of abnormal muscle tissue breakdown called rhabdomyolysis. When the breakdown products of rhabdomyolysis pass through the bloodstream to the kidneys, they can trigger failure by blocking and damaging vital structures within these paired organs.
Methamphetamine and Hyperthermia
Like amphetamine, methamphetamine achieves its primary consciousness-altering effects by boosting brain levels of a substance called dopamine, which helps activate the brain’s reward or pleasure centers. Both amphetamine and methamphetamine produce a dopamine increase by stopping the normal recycling process that breaks this chemical down after its initial use. However, methamphetamine produces an even bigger increase by simultaneously increasing the release of new dopamine supplies inside the brain. Because of this dual action, methamphetamine creates unusually powerful euphoric effects within the user.
In addition to its primary mental effects, methamphetamine has a variety of secondary physical effects. Among these effects is the promotion of hyperthermia, a condition that occurs when temperatures in the brain and/or body exceed the safe limits normally enforced by several different internal regulatory processes. Underlying meth-related causes for this damaging temperature increase include abnormal contraction (tightening) and twitching in muscles throughout the body and overstimulation of an involuntary nerve network called the sympathetic nervous system, which carries out the survival-oriented reaction to stress and danger known as the “fight-or-flight” response.
Hyperthermia can easily raise the normal temperature inside the body’s main voluntary muscles, also known as the skeletal muscles. At a certain point, this temperature increase will damage the cells inside these muscles and trigger the release of a protein called myoglobin. When it’s contained inside muscle tissue, myoglobin plays an important role by providing an extra oxygen boost during periods of high muscle activity. However, when it gets released from this tissue, it travels through the bloodstream until it reaches the filtering structures inside the kidneys, which are designed to remove waste and excess water from the circulating blood supply. Doctors refer to the whole process of muscle tissue breakdown and myoglobin release as rhabdomyolysis.
Myoglobin Buildup and Kidney Failure
When myoglobin reaches the kidney’s filtering structures, it breaks down into smaller units of waste. The kidneys can handle a certain amount of these breakdown products. However, people with rhabdomyolysis typically experience a fairly large-scale myoglobin release, and the breakdown particles generated by this release can easily overwhelm the kidneys by blocking their filtration system and damaging the individual cells that form this system. The end result of this chain of events is acute kidney failure (also known as acute renal failure), a condition that occurs when the kidneys rapidly or suddenly lose their normal ability to remove waste and regulate fluid levels. If left uncorrected, this failure can lead to permanent damage of the kidneys’ filtration abilities, or a complete loss of these abilities that leads to death.
Specific Circumstances and At-Risk Groups
Methamphetamine-related hyperthermia, rhabdomyolysis, and kidney failure typically occur in people who use/abuse enough of the drug to overdose. Population groups most likely to experience a methamphetamine overdose include first-time users, generally inexperienced users, long-term users with weakened immune systems, and users who take the drug by injecting it into their veins. Practically speaking, these groups as a whole represent a clear majority of all methamphetamine users. According to a study review published in 2009 in the journal Nursing, roughly 7 percent of all rhabdomyolysis cases in the US involve people who overdose on methamphetamines.
In addition to myoglobin, rhabdomyolysis releases several other substances into the bloodstream, including potassium, phosphate and creatine phosphokinase. Apart from kidney failure, the release of these materials can trigger a potentially fatal increase in blood acidity called metabolic acidosis. In addition, methamphetamine overdose can trigger kidney failure through other mechanisms besides rhabdomyolysis. These mechanisms include abnormally low blood oxygen levels (hypoxemia), a form of kidney cell death called acute tubular necrosis, a form of artery inflammation called necrotizing angiitis, and a form of swelling inside the kidneys called acute interstitial nephritis.