Rhabdomyolysis

Background

• Muscle necrosis and the release of intracellular muscle constituents into the circulation
• Causes
  • 1. Traumatic or muscle compression
    • a. Crush injury
    • b. Immobilization
    • c. Compartment syndrome
  • 2. Nontraumatic exertional
    • a. Exercise + hot weather
    • b. Exercise + sickle cell
    • c. Exercise + hypokalemia
    • d. Hyperkinetic states
      • Seizure
      • DTs
      • Stimulant overdose
      • Malignant hyperthermia
      • NMS
  • 3. Nontraumatic nonexertional
    • a. Drugs and toxins
      • Coma induced by sedatives
      • Statins
      • Colchicine
      • CO poisoning
    • b. Infection
      • Viral myositis - Influenza, Coxsackie, EBV, HSV, HIV, CMV
      • Bacterial pyomyositis
      • Septicemia
    • c. Endocrine
      • Hypothyroidism
    • d. Inflammatory myopathies
      • Moderate CK elevations only (rhabdo only described in case reports)
    • e. Miscellaneous
      • Status asthmaticus
      • TSS
      • Mushroom ingestion

Diagnosis

Clinical

• Myalgias
  • May progress to weakness
• Red/brown urine
• Renal failure

Laboratory

• Elevated total CK (typically > 10K)
  • CK-MB may be entirely normal or may be mildly elevated (reflects small amount found in skeletal tissue)
• Transaminitis
• Creatinine increase (if renal failure)
• Myoglobinuria
  • Is cleared much faster than CK (may see elevated CK with no myoglobinuria)
• Electrolyte Abnormalities
  • Hyperkalemia
  • Hyperphosphatemia
  • Hypocalcemia
  • Hyperuricemia
  • Metabolic acidosis

Treatment

1. Aggressive IVF

• Often up to 10L per day)

    -type of fluid = controversial     -NaBicarb (to alkalize urine)          -may exacerbate the symptoms of the initial hypocalcemic phase of rhabdomyolysis.          -urine pH and serum bicarbonate, calcium, and potassium levels should be monitored          -if urine pH does not rise after 4 to 6 hours of treatment or if symptomatic hypocalcemia develops, alkalinization should be discontinued and hydration continued with NS2) Monitor electrolytes     -correct hyperkalemia     -early hypocalcemia should NOT be treated unless symptomatic or severe hyperkalemia present     -Calcium-containing chelators should be used with caution to treat hyperphosphatemia, since the calcium load could increase the precipitation of calcium phosphate in injured muscle.==Disposition==

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Evidence Based Questions

No randomized, controlled trial has supported the evidence-based use of mannitol, and some clinical studies suggest no beneficial effects. In addition, high accumulated doses of mannitol (>200 g per day or accumulated doses of >800 g) have been associated with acute kidney injury due to renal vasoconstriction and tubular toxicity, a condition known as osmotic nephrosis. However, many experts continue to suggest that mannitol should be used to prevent and treat rhabdomyolysis-induced acute kidney injury and relieve compartmental pressure. During the time mannitol is being administered, plasma osmolality and the osmolal gap (i.e., the difference between the measured and calculated serum osmolality) should be monitored frequently and therapy discontinued if adequate diuresis is not achieved or if the osmolal gap rises above 55 mOsm per kilogram.

A. Bozch X et al. Rhabdomyolysis and Acute Kidney Injury. NEJM 2009; 361: 62-72

See Also

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Source

KajQuestions