Background

Rhabdomyolysis is a condition caused by damage to skeletal muscle. In sports, the muscle damage happens with excessively strenuous exercise, but it can also be caused by crushing injuries to the body, some medications, toxins, or infections. When the muscle is damaged, potentially toxic contents within the muscle cells (creatine phosphokinase or CPK, myoglobin, potassium, phosphate, uric acid) are released into the blood stream. In small amounts, the body is typically capable of filtering and clearing these toxins. If the injury is severe enough to cause a massive release of toxins, the body may be unable to adequately clear them. These toxins can cause irregular heartbeats, kidney damage, and, in severe cases, death.

Symptoms

Signs and symptoms of rhabdomyolysis include:

Classic Triad

1. Muscle pain (myalgias)
2. Muscle weakness
3. Dark-colored urine

Other:

• Decreased urination
• Fever
• Malaise
• Nausea or Vomiting
• Confusion and/or agitation (delirium)

Sports Medicine Evaluation and Treatment

A sports medicine physician will review symptoms and evaluate for muscle pain, swelling, and weakness. The diagnosis is made through blood and urine testing. Urine tests looks for the presence of muscle breakdown products (myoglobin) to help diagnose the condition. Blood tests look for an elevation in the enzyme CPK, and are used for diagnosis and to monitor the extent of disease. This enzyme is stored within the muscles and released into the blood stream when muscle is damaged. Elevations can be seen in the first few hours after the injury but may not peak for 36 hours to a few days after the muscle injury. Elevations up to 1,000 units/L indicate rhabdomyolysis. CPK levels above 16,000 units/L indicate risk for kidney damage. Repeat blood testing to look at kidney function and electrolytes may be needed to monitor the severity of rhabdomyolysis.

Often, the athlete needs to be admitted to the hospital. Treatment for rhabdomyolysis includes hydration with fluids through the veins (IV normal saline). This treatment serves to wash out the excess myoglobin and improve kidney function. Severe cases might require filtering of the blood (hemodialysis). Treatment is completed when creatine phosphokinase levels in the blood fall below 1,000 units/L and no myoglobin is detected in the urine.

Injury Prevention

Rhabdomyolysis is preventable. Gradually and steadily increasing the intensity of one’s exercise program is the key to avoiding rhabdomyolysis. Rhabdomyolysis is often seen in situations where an athlete aggressively pushes his/her body past normal limits, often in a competitive setting. In addition, athletes should be aware of risk factors for rhabdomyolysis that includes recent alcohol use, use of certain medications including cholesterol-lowering medicines, and ongoing infection. Staying well-hydrated, especially while exercising during hot and humid conditions, can also help prevent rhabdomyolysis.

Return to Play

Return to activity after an episode of rhabdomyolysis is done in coordination with a sports medicine physician. It is important to be guided through a gradual, stepwise return to sports, beginning with light, non-strenuous activity. This return to play process may take 2-8 weeks depending on previous activity levels and the severity of the episode of rhabdomyolysis.

AMSSM Member Authors
Jon-Michael Cook, MD and Vijay Jotwani, MD

References
Rhabdomyolysis. WebMD. http://www.webmd.com/a-to-z-guides/ rhabdomyolysis-symptoms-causes-treatments#1. Accessed February 22, 2017.
Rhabdomyolysis. Rhabdomyolysis: Practice Essentials, Background, Pathophysiology. http://emedicine.medscape.com/article/1007814-overview. Accessed February 22, 2017.
Moses MDS. Rhabdomyolysis. Family Practice Notebook. http://www. fpnotebook.com/renal/Failure/Rhbdmylys.htm. Published February 5, 2017. Accessed February 22, 2017.