Rhabdomyolysis

Physicians first described rhabdomyolysis in the medical literature during ancient times; however, in our modern era, a notable number of cases were reported during World War I and II in soldiers who sustained crush injuries from bombings and trench collapses. Rhabdomyolysis is a condition that results when damaged muscles release toxic muscular contents (fluids) into the bloodstream. In healthy skeletal muscle, each muscle fiber is enclosed in a thin membrane that controls a number of pumps that regulate and maintain the electrolyte concentration inside and outside the cell. Electrolytes are minerals—the 4 basic are magnesium, calcium, sodium, and potassium—in your blood and other body fluids that carry an electric charge. The proper balance of electrolytes and other nutrients provided by normal blood flow allow muscles to contract and relax in response to nerve stimulation. Any direct or indirect injury to the membrane can cause damage and the breakdown of muscle cells, resulting in toxic muscular contents to leak into the body’s circulation (Fig).

What causes rhabdomyolysis to occur?

You can develop rhabdomyolysis from muscle damage in a number of ways, but the most common causes are trauma that leads to muscle compression and crush-type injuries, muscle overexertion from excessive exercise, and the abuse or overuse of drugs, alcohol, and certain medications (Table). Regardless of the cause, the results of a muscle injury can cause a cascade of events that leads to the release of toxic muscle byproducts into the bloodstream that not only affects your muscles, but also your organs and the rest of the body. In a crush injury—for example when a patient is trapped in a car or collapsed building—muscle dies when the blood flow is cutoff. When the compression is relieved, fluids from the damaged muscle are released into the bloodstream.

Additionally, excessive or intense exercise beyond the extent of a person’s physical limits can cause exercise-induced rhabdomyolysis. The primary factors that tend to worsen this condition include the level of physical fitness, the intensity, and types of exercise. Exercise-induced rhabdomyolysis tends to occur in individuals who are poorly conditioned, during long durations of exercise, in high humidity and temperatures, and during excessive exercise while taking drugs or drinking alcohol. Physicians have treated exercise-induced rhabdomyolysis in military recruits, and participants of marathons, triathlons, soccer, crossfit, weight lifting, and numerous other sports.

Another cause occurs during prolonged immobilization from anesthesia, coma, or drug- or alcohol-induced unconsciousness when unrelieved pressure on a gravity-dependent body part is present. There are multiple reports of a person developing rhabdomyolysis from drug or alcohol induced comas in which their arm or leg was compressed against a firm object or another body part which decreased blood flow to the extremity for multiple hours causing muscle damage.

Symptoms

Symptoms of rhabdomyolysis can vary depending on the extent of your muscle damage; however, the classic symptoms are severe muscle pain with weakness to the point you will have trouble moving your arms or legs, and you may experience dark red or brown urine or decreased urination. Additionally, local symptoms around the injured area can include muscle pain, weakness, swelling, extreme soreness, stiffness, cramping, bruising, and tenderness. You can also experience an overall sickly feeling with fever, abdominal pain, nausea, and vomiting. Occasionally changes in mental status, such as confusion or loss of consciousness can occur.

Diagnosis

Physicians use laboratory tests that detect excess muscle proteins and enzymes in the blood and urine to diagnose rhabdomyolysis. A careful history and physical exam may reveal the underlying cause or at least aid in the selection of the most appropriate diagnostic workup.

Complications

Complications from rhabdomyolysis can be numerous and severe. As the toxic fluids pour into the bloodstream from damaged muscle tissue it can affect not only local tissue but also organs throughout the body. More locally, compartment syndrome can occur when increased pressure builds up within a muscle compartment resulting in decreased oxygenation to the local tissues. Irregular heartbeats and even cardiac arrest can occur from electrolyte dysfunction as well. For example, a patient may experience high levels of potassium in the blood, which can cause an irregular heartbeat. Muscle byproducts can also cause liver dysfunction, which occurs in approximately 25% of rhabdomyolysis cases. Other complications include increased blood clotting, low blood pressure, and shock. Kidney failure is also one of the most serious complications in the days following the initial presentation of rhabdomyolysis.

Permanent kidney injury and even death can occur as a result in very severe cases.

Treatment

After muscle damage has occurred, the main treatment of rhabdomyolysis includes aggressive fluid resuscitation (IV fluids) to avoid kidney injuries. Once in a hospital setting, aggressive fluid resuscitation will continue along with a careful history and physical exam to identify and manage any complications. Management of complications can include cardiac monitoring, medications to correct electrolyte imbalances and irregular heartbeats, surgery to alleviate elevated pressures in an extremity, physical therapy, close monitoring of kidney function, and use of dialysis in severe cases of kidney injury.

Recovery

Recovery from rhabdomyolysis varies and depends on the degree of muscle damage and the specific complications that occurred. If the condition is recognized and treated early, you can avoid most major complications and expect a full recovery. Recovery from exercise-induced rhabdomyolysis, with no major complications, can take several weeks to months for the patient to return to exercise without recurrence of symptoms. More severe complications, such as those often seen in compartment syndrome, can result in multiple operations, months of rehabilitation, and permanent disability. Additionally, the kidney dysfunction that results from rhabdomyolysis often resolves, however, if you experience severe kidney injury it can result in permanent damage and a need for long-term treatments, perhaps even dialysis.

Prevention

Prevention is geared toward avoiding what causes rhabdomyolysis; but you can only avoid what you have control over. You cannot always prevent an accident or injury; however, you do have control over exercise-induced rhabdomyolysis. Exercise-induced rhabdomyolysis can be prevented by initiating a gradual training program with sufficient recovery time included, avoiding extreme exercises, preserving fluid balance, and not exercising in high heat and humidity.

A rare condition

Luckily, rhabdomyolysis is a rare condition, especially since it can have serious and long-lasting complications. While you cannot always avoid an injury, patients can steer clear of the complications by minimizing the risk factors that they can control. If a crush injury occurs or if you experience the symptoms of rhabdomyolysis, the best results will come if a physician promptly identifies and treats the condition.

Author: David Barnes, DO

Reprinted with permission from the Hughston Health Alert, Volume 30, Number 3, Summer 2018.