Rhabdomyolysis: Difference between revisions

Line 106: Line 106:
###Arterial pH > 7.5
###Arterial pH > 7.5
###Serum bicarbonate >30 meq/L
###Serum bicarbonate >30 meq/L
#Mannitol
#[[Mannitol]]
##Controversial; no RCT to date has demonstrated benefit
##Controversial; no RCT to date has demonstrated benefit
##Mannitol administration can worsen dehydration and oliguria, cause hyperkalemia
##Mannitol administration can worsen dehydration and oliguria, cause hyperkalemia

Revision as of 21:28, 21 January 2015

Background

  • Muscle necrosis and release of intracellular muscle constituents into the circulation
  • Recurrent episodes suggests inherited metabolic disorder
  • Alcohol and drugs play a role in up to 80% of cases

Etiology

  1. Trauma or muscle compression
    1. Crush Syndrome
    2. Immobilization
    3. Compartment Syndrome
  2. Nontraumatic Exertional
    1. Exercise + hot weather
    2. Exercise + sickle cell
    3. Exercise + Hypokalemia
    4. Hyperkinetic states
      1. Seizure
      2. DTs
      3. Stimulant overdose
      4. Malignant Hyperthermia
      5. Neuroleptic malignant syndrome
  3. Nontraumatic Nonexertional
    1. Drugs and toxins
      1. Coma induced by sedatives
      2. Alcohol
        1. Coma-induced muscle compression
        2. Direct toxic effect
        3. Nutritional compromise increases risk (hypoK, hypoMg, HypoPhos)
      3. Statins
      4. Colchicine
      5. CO Poisoning
    2. Infection
      1. Viral myositis - Influenza, Coxsackie, EBV, HSV, HIV, CMV
      2. Bacterial pyomyositis
      3. Septicemia
    3. Endocrine
      1. Hypothyroidism
    4. Inflammatory myopathies
      1. Moderate CK elevations only (rhabdo only described in case reports)
    5. Miscellaneous
      1. Status Asthmaticus
      2. TSS
      3. Mushroom ingestion

Differential Diagnosis

Red Urine

Clinical Features

  1. Myalgia, stiffness, weakness, malaise, low-grade fever, dark urine
    1. Musculoskeletal symptoms may be present in only half of cases
  2. N/V, abd pain, tachycardia in severe cases
  3. Mental status changes secondary to urea-induced encephalopathy

Work-up

  1. Total CK
  2. UA
  3. CBC
  4. Chemistry, including Mag, Phos
  5. Uric acid
  6. LFTs
  7. DIC panel
    1. Coags, FSP, fibrinogen

Diagnosis

  1. Total CK
    1. Most consider rhabdo if 5x or greater increase above upper limit of normal (~2000)
    2. Serum CK begins to rise 2-12hr after injury, peaks w/in 24-72hr
    3. Degree of CK elevation correlates w/ muscle injury, but NOT renal failure
  2. CK-MB
    1. May be normal or mildly elevated (<5% of total)
  3. Uric Acid - elevates before CK
  4. Myoglobinuria
    1. UA = +blood, no RBCs (Sn ~80%)
    2. Myoglobin is cleared w/in 1-6hr (often see elevated CK with no myoglobinuria)
  5. Acute renal failure
    1. Creatinine increase
  6. Electrolyte abnormalities
    1. Hyperkalemia
    2. Hyperphosphatemia
    3. Hypocalcemia
    4. Hyperuricemia

Management

  1. Aggressive IVF
    1. Start with NS 1-2 L/hr
    2. Once diuresis occurs maintain urine output of 200-300 mL/hr
    3. Frequently need ~10 L/day
  2. Trend:
    1. Volume status
    2. Urine pH
    3. Chemistry
    4. CK
    5. Calcium, phosphorus
  3. Urinary alkalinization (with bicarbonate)
    1. Controversial; no RCT to date have demonstrated benefit
    2. Consider if CK >5000, severe muscle injury (crush injury), rising CK AND urine pH <6.5
    3. Contraindications:
      1. Severe hypocalcemia
      2. Arterial pH > 7.50
      3. Serum bicarbonate > 30 meq/L
    4. Mix 150 mL [3 amps] of 8.4% sodium bicarbonate w/ 1 L D5W
    5. Infuse at 200 mL/hour; rate is adjusted to achieve urine pH of >6.5
    6. Arterial pH and serum calcium should be monitored q2hr
    7. Discontinue if:
      1. Urine pH does not rise above 6.5 after 3-4hr
      2. Pt develops symptomatic hypocalcemia
      3. Arterial pH > 7.5
      4. Serum bicarbonate >30 meq/L
  4. Mannitol
    1. Controversial; no RCT to date has demonstrated benefit
    2. Mannitol administration can worsen dehydration and oliguria, cause hyperkalemia
    3. Consider in pts w/marked elevations in CK (>30K)
    4. Contraindicated if urinary flow is inadequate (<20 mL/hr)
    5. Add 50 mL of 20% mannitol to each liter of fluid; give at rate of 5g/hr
    6. Must check plasma osmolaity and plasma osmolal gap q4-6hr
      1. Discontinue if osmolal gap > 55 mosmol/kg
  5. Intubation/RSI
    1. Use Rocuronium

Disposition

  1. Discharge if:
    1. Exertional rhabdo
    2. Otherwise healthy
    3. No comorbidities (heat stress, dehydration, trauma)
    4. Downtrending total CK
      1. Consider admission for CK >30,000
  2. Otherwise admit to monitored bed

Complications

  1. Acute Renal Failure
    1. Neither presence of myoglobinuria nor degree of CK rise is predictive of ARF
    2. Rare in exertional rhabdo w/o presence of dehydration, heat stress, trauma
    3. Most commonly oliguric
  2. Hyperkalemia
    1. Renal function, not release of K+, is most important determinant
    2. Treat aggressively; insulin may be ineffective; may require dialysis
  3. Hypocalcemia (initial phase)
    1. Treat only if symptomatic or severely hyperkalemic (often have rebound hypercalcemia)
  4. Hypercalcemia (recovery phase)
  5. Hyperphosphatemia
    1. Treat cautiously (treatment may worsen calcium precipitation in muscle)
    2. Consider oral phosphate binders when level >7
  6. DIC
    1. Usually resolves spontaneously w/in several days
  7. Compartment Syndrome
  8. Peripheral nerve injury
    1. Usually resolves w/in few days-weeks

See Also

Source

  • Tintinalli
  • UpToDate