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rhabdomyolysis

rhabdomyolysis

introduction

  • skeletal muscle necrosis may cause death either by:
    • releasing heme pigments such as myoglobin into the circulation which may result in acute renal failure, particularly if there is hypovolaemia and poor renal flow.
    • releasing potassium and phosphate into the circulation causing hyperkalaemia and hyperphosphataemia
    • severe hypocalcaemia due to deposition of calcium salts in damaged muscle and decreased bone responsiveness to parathyroid hormone
  • localised necrosis may also cause odema resulting in compartment syndrome
  • low likelihood of acute renal failure when peak creatine kinase levels are under 5,000 - 10,000 U/L
  • A problem that is unique to rhabdomyolysis-induced acute renal failure is the development of hypercalcaemia during the recovery phase in approximately 20 to 30 percent of patients

aetiology

mechanical injury

  • traumatic crush injury, particularly those trapped in vehicles after motor vehicle accidennts, or in collapsed buildings from earthquakes
  • prolonged muscle ischaemia from immobilisation such as patients lying comatose for hours before being found
  • prolonged ischaemia from tourniquets or muscle compression such as during prolonged surgical procedures
  • near drowning causing prolonged hypoxia &/or vasoconstriction

exertional

metabolic

  • inherited disorders of glycogenolysis, glycolysis, or lipid or purine metabolism

toxins

infections

electrolyte and endocrine disorders

inflammatory myopathies

  • dermatomyositis
  • polymyositis

ED Mx of rhabdomyolysis

  • predict potential hyperkalaemia and cardiac arrest on return of circulation to a crushed limb
  • be aware - check CK level in those at risk
  • treat underlying cause
  • ensure adequate saline rehydration to prevent renal failure - start early - consider 1-2L/hour iv 0.9% saline initially if fluid overload is not a risk. Adjust to maintain the desired diuresis of approximately 200 to 300 mL/hour.
  • cardiac monitor and check FBE, U&E, CK
  • monitor fluid balance and urine output
  • consider attempted prevention of acute renal failure with forced mannitol-alkaline diuresis in an effort to diminish the renal toxicity of myoglobin.
  • Mx acute renal failure (ARF) if occurs as usual but watch for hypercalcaemia thus avoid giving calcium in Mx
rhabdomyolysis.txt · Last modified: 2019/06/27 17:38 (external edit)