Rhabdomyolysis

Rhabdomyolysis will typically feature in the exam as a patient who has had a fall or prolonged epileptic seizure and is found to have an acute kidney injury on admission.

Causes

• seizure
• collapse/coma (e.g. elderly patient collapses at home, found 8 hours later)
• ecstasy
• crush injury
• McArdle's syndrome
• drugs: statins (especially if co-prescribed with clarithromycin)

Features

• acute kidney injury with disproportionately raised creatinine
• elevated creatine kinase (CK)
  • the CK is significantly elevated, at least 5 times the upper limit of normal
  • elevations of CK that are 'only' 2-4 times that of normal are not supportive of a diagnosis and suggest another underlying pathophysiology
• myoglobinuria: dark or reddish-brown colour
• hypocalcaemia (myoglobin binds calcium)
• elevated phosphate (released from myocytes)
• hyperkalaemia (may develop before renal failure)
• metabolic acidosis

Management

• IV fluids to maintain good urine output
• urinary alkalinization is sometimes used