Rhabdomyolysis is a condition in which skeletal muscle tissue dies, releasing substances into the blood that cause kidney failure.
Rhabdomyolysis is usually caused by a specific event. This is most commonly injury, overexertion, infection, drug use, or the use of certain medications.
The condition is fairly rare, with roughly 26,000 new cases in the United States each year. In most cases, the first recommended line of treatment is giving fluids directly through the veins. Severe symptoms may require kidney dialysis and blood filtration.
When skeletal muscle tissues are damaged or die, their components are broken down. These components are then released into the bloodstream to be filtered and removed from the body.
Several of these components can lead to kidney damage, with the most common being the protein pigment myoglobin.
Myoglobin can block the complex tubing system of the kidney. If blockages become severe enough, kidney damage and failure can occur. Other cellular enzymes, especially creatine kinase (CK), also put stress on the kidney.
Damaged muscle tissues also retain body fluids. This can cause dehydration as well as reduce the flow of blood to the kidney, thereby increasing the risk of organ damage.
The complications associated with rhabdomyolysis depend on the severity of the case and on several individual factors. Minor cases may not cause any noticeable symptoms and might only be spotted with blood serum tests. Severe cases often cause severe muscle pain, however, and can be life-threatening.
Most cases of rhabdomyolysis are considered a part of crush syndrome, a condition that occurs as the result of traumatic skeletal muscle injury. But generally, anything that causes muscle injury, dehydration, or kidney injury increases a person’s chances of developing the condition.
Many cases not caused by direct trauma are considered to be the result of several different factors.
Researchers are still exploring the full range of factors that may influence the risk of rhabdomyolysis. Currently, cases of rhabdomyolysis are classified as one of the following:
- the result of external injury, infection, or substances
- inherited, caused by genetic conditions such as muscular myopathies
There are many causes and risk factors for rhabdomyolysis that are currently recognized. These include the following:
- crushing damage to skeletal muscle tissues
- not being able to move for a prolonged period of time
- overexertion of muscles
- heatstroke or overexertion in extreme environments
- extensive burns that cause muscle damage
- hereditary muscle disorders known as metabolic myopathies
- dietary supplements or weight-loss supplements, especially those containing ephedra and creatine
- infections, in particular bacterial and viral infections that cause blood infections
- electrolyte disorders, especially those affecting potassium and calcium
- endocrine disorders, such as hypothyroidism and hyperthyroidism
- kidney disease or disorders
- heart attack or stroke, which can lead to muscle injury and not being able to move
- vascular or cardiac surgery, which often causes muscle damage and requires long periods of immobilization during and after it
- sickle cell anemia
- inflammatory muscle conditions
Another possible cause is exposure to toxins, such as excessive or long-term alcohol or drug use. This also includes exposure to environmental toxins, including reptile or insect venom, mold, and carbon monoxide.
Certain medications can also lead to rhabdomylosis. For example, the condition is estimated to arise in an estimated 0.3 to 13.5 cases out of every 1 million statin prescriptions made. Other medications include anti-psychotic medications and those used to manage muscular conditions such as Parkinson’s disease.
Although mild cases may not cause symptoms, most people with rhabdomyolysis experience a common set of complaints. Most symptoms first appear within hours to days after the condition develops or a cause has occurred.
Common early symptoms of rhabdomyolysis include:
- muscle pain, often extremely painful aching and throbbing
- muscle weakness
- muscle swelling or inflammation
- dark-, cola-, or tea-colored urine
- general exhaustion or fatigue
- irregular heartbeat
- dizziness, light-headed, or feeling faint
- confusion or disorientation
- nausea or vomiting
Medical attention should be sought any time that symptoms of rhabdomylosis occur. Untreated cases can become serious and may cause life-threatening complications such as kidney failure.
Most physicians begin by reviewing patient medical history, considering factors including injury, overexertion, medication use, and other health conditions or symptoms.
To make a diagnosis, laboratory confirmation is normally required. This tends to involve detection of elevated CK levels in the blood and the presence of myoglobin in the urine.
In many instances, muscle biopsies are also carried out to confirm and assess muscle damage.
CK levels that are five times the upper limit of normal levels are considered to be evidence of rhabdomyolysis. The definition of normal CK levels in the blood varies by sex, race, and ethnicity.
Activity or physical exertion may raise CK levels temporarily. As a result, tests should be done after avoiding rigorous activity for roughly 7 days.
Genetic testing may also be performed in people with suspected cases of rhabdomyolysis, in order to check for the presence of inherited muscle conditions. Once additional conditions are confirmed, they can be treated, thereby reducing symptoms and the likelihood of the condition returning.
Treatment depends on the severity of the case, symptoms, and presence of additional health complications that may increase the risk of kidney damage. In severe cases, kidney damage can be irreversible without early treatment.
One treatment method is intravenous fluid therapy. Large volumes of water are often administered to the veins for long time in order to rehydrate the body and flush out any myoglobin.
Other treatment options for severe rhabdomyolysis include:
- urine alkalization
- filtration of the blood (in very severe cases)
The easiest way to prevent rhabdomyolysis is to avoid prolonged periods of immobilization, stay hydrated, and exercise within healthy limits.
Other common tips to help prevent the condition include:
- avoiding weight-loss, muscle gain, or performance-enhancing dietary supplements, especially those containing creatine, ephedrine, ephedra, or high levels of caffeine
- listening to one’s body when exercising and not going beyond what feels comfortable or natural to do
- seeking training advice if attempting a major physical event (such as running a marathon)
- increasing workout intensity and frequency slowly
- treating conditions or complications that are considered to be risk factors
- seeking immediate medical attention as soon as symptoms occur or if the condition is suspected