Description

• Breakdown of skeletal muscle with systemic release of intracellular contents
• Rhabdomyolysis typically presents with muscle pain, weakness, and reddish brown (tea-colored) urine. Up to 50% of patients are asymptomatic.

Epidemiology

Incidence
26,000 hospitalizations annually in United States

Etiology and Pathophysiology

Risk factors

• Direct muscle trauma (most common cause)
  • Crush injuries
  • Extended periods of muscle pressure (during surgery, unconscious from alcohol ingestion)
  • Burns, electrocution, lightning strike
• Muscle exertion
  • Intense and/or prolonged physical exercise (marathon runners, athletes, contact sports)
  • Seizures
  • Delirium tremens
• Drugs and toxins
  • Alcohol
  • Cocaine (most common recreational drug), methamphetamine, phencyclidine, heroin, bath salts (1)[B]; synthetic marijuana has been associated with severe rhabdomyolysis.
  • Antipsychotics (due to neuroleptic malignant syndrome, malignant hyperthermia, and dystonia)
  • Zidovudine
  • Antimalarials
  • HMG-CoA reductase inhibitors (statins) (risk <0.01%—elevated with higher doses and in combination with fibrates)
  • Colchicine
  • Corticosteroids
  • Carbon monoxide
  • Snake envenomation
• Muscle ischemia
  • Thrombosis, embolism, sickle cell disease
  • Compartment syndrome
  • Tourniquets
• Infections
  • Viral: influenza A and B, coxsackievirus, HIV, varicella
  • Bacterial: Streptococcus or Staphylococcus sepsis, gas gangrene, necrotizing fasciitis, Salmonella, Legionella
  • Malaria
• Hypothermia
• Hyperthermia
• Autoimmune disorders
  • Polymyositis, dermatomyositis
• Metabolic and endocrinologic:
  • Hypothyroidism or thyrotoxicosis
  • Electrolyte imbalances (e.g., hyponatremia, hypernatremia, hypokalemia, hypocalcemia, hypophosphatemia)
  • Diabetic ketoacidosis
  • Hyperosmolar state

Genetics
Hereditary causes of rhabdomyolysis are rare but should be suspected in children; patients with recurrent attacks; or patients who have attacks after minimal exertion, mild illness, or starvation.

• Genetic disorders (1)[C]
  • Muscular dystrophies
  • Disorders of lipid metabolism (e.g., carnitine palmitoyltransferase deficiency)
  • Disorders of carbohydrate metabolism (i.e., phosphofructokinase deficiency, phosphoglycerate mutase, myophosphorylase deficiency, a.k.a. McArdle disease/deficiency)
  • Glycogen storage diseases (e.g., phosphorylase B kinase deficiency) and others (e.g., lactate dehydrogenase A deficiency)
  • Mitochondrial disorders

General Prevention

• Avoid excessive exertion; ensure adequate hydration.
• Avoid precipitating drugs, metabolic and electrolyte abnormalities.