Consider rhabdomyolyisis secondary to heat exposure as summertime approaches; have a low threshold to screen patients if they are at risk (e.g., people exercising in high-ambient temperatures).

Symptoms include muscle tenderness, cramping, and swelling with associated weakness. Patients with altered mental status (e.g., heat stroke) should be examined for limb induration, skin discoloration (i.e., ischemia), or compartment syndrome.

Complications:

• Electrolyte abnormalities (e.g., hyperkalemia and hypocalcemia) and malignant cardiac arrhythmias
• Metabolic acidosis
• Disseminated intravascular coagulation (release of tissue factor from muscle cells)
• Acute renal failure (myoglobin directly causes nephrotoxicity)

Treatment

• External cooling to cease the inciting process
• Aggressive fluid resuscitation with normal saline (avoid lactated ringers) for goal urine output of 200 to 300 ml/hour; foley catheters should be placed to monitor urine output.
• Start dialysis if potassium levels are elevated, acidosis, or oliguric renal failure. There is very limited evidence for the use of dialysis before the presence of these signs.
• There are no randomized controlled trials to support the use of mannitol (free radial scavenger and diuretic) or bicarbonate (to alkalinize the urine); their use is controversial.

References

Khan, F. Y. Rhabdomyolysis: a review of the literature. The Netherlands journal of medicine, 67(9), 272 – 283.

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