Exertional Rhabdomyolysis: Epidemiology, Diagnosis, Treatment, and Prevention

Exertional rhabdomyolysis (ER) is a medical condition whereby damage to skeletal muscle is induced by excessive physical activity in otherwise healthy individuals. The individual performs so much activity that he/ she presumably depletes local muscle energy stores and muscle cells are unable to maintain cellular integrity, resulting in cell damage and the release of cellular contents, with resultant secondary complications. In the military services, the incidence of ER appeared to increase in the period 2004 to 2015. Risk factors for ER include male sex, younger age, a prior heat injury, lower educational level, lower chronic physical activity, and activity in the warmer months of the year. Acute kidney injury is the most serious potential complication of ER and is thought to be due to a disproportionate amount of free myoglobin that causes renal vasoconstriction, nephrotoxic effects, and renal tubular obstructions. Patients typically present with a history of heavy and unaccustomed exercise with muscle pain, swelling, weakness, and decreased range of motion, largely localized to the muscle groups that were involved in the activity. Diagnostic criteria include the requisite clinical presentation with a serum creatine kinase level at least level 5 times higher than the upper limit of normal and/ or a urine dipstick positive for blood (due to the presence of myoglobin) but lacking red blood cells under microscopic urinalysis. Core treatment is largely supportive with aggressive fluid hydration. Although the great majority of individuals return to activity without consequence, patients should initially be stratified into high and low risk for recurrence, and those at high risk provided additional evaluation. Risk of ER in normal healthy individuals can be reduced by emphasizing graded, individual preconditioning before beginning a more strenuous exercise regimen after recommended work/rest and hydration schedules in hot weather, and discussing supplements and medications with knowledgeable medical personnel.