What is the treatment for Rhabdomyolysis (muscle breakdown disease) with a rash?

Treatment of Rhabdomyolysis with Rash

The cornerstone of treatment for rhabdomyolysis with rash is aggressive intravenous fluid resuscitation, with high-dose corticosteroids indicated when the rash suggests an immune-mediated cause such as immune checkpoint inhibitor-induced myositis or dermatomyositis. 1, 2

Diagnosis and Assessment

• Rhabdomyolysis with rash may indicate immune-mediated myositis, particularly in patients receiving immune checkpoint inhibitors (ICPis), which can present with dermatomyositis-like features 2
• Laboratory assessment should include:
  • Creatine kinase (CK) levels, which are typically markedly elevated (>5 times upper limit of normal) 1, 3
  • Inflammatory markers (ESR, CRP) which are usually elevated in immune-mediated causes 2
  • Electrolytes, particularly potassium, as hyperkalemia can lead to cardiac arrhythmias 1, 4
  • Myoglobin levels in serum and urine 5
• Additional diagnostic tests may include:
  • Autoantibody panels for myositis, though specific autoantibodies for ICPi-associated myositis are not well established 2
  • MRI showing increased intensity and edema in affected muscles 2
  • EMG which may show muscle fibrillations indicative of myopathy 2
  • Muscle biopsy to confirm diagnosis in unclear cases 2

Treatment Algorithm

First-Line Treatment

• Aggressive intravenous fluid resuscitation is the mainstay of treatment 1, 6

  • For severe rhabdomyolysis (CK >15,000 IU/L), volumes greater than 6L may be required 1
  • For moderate cases, 3-6L per day is typically sufficient 1
  • Target urine output should be at least 300 mL/hour 5, 3

• For cases with rash suggesting immune-mediated etiology:

  • High-dose corticosteroids should be administered, as a bolus in severe cases 2
  • Consider plasmapheresis in cases with poor response to corticosteroids or in life-threatening situations 2

Management of Complications

• Monitor and correct electrolyte abnormalities 1, 4

  • Hyperkalemia requires urgent treatment to prevent cardiac arrhythmias 1, 4
  • Early hypocalcemia and late hypercalcemia may occur 4
  • Metabolic acidosis may require correction 4

• Assess for compartment syndrome 1, 2

  • Early signs include pain, tension, paresthesia, and paresis 1
  • Late signs include pulselessness and pallor, indicating irreversible damage 1
  • Consider fasciotomy when compartment pressure exceeds 30 mmHg or when differential pressure is <30 mmHg 1
  • Early fasciotomy is indicated for established compartment syndrome 1

• For immune-related myositis with rash:

  • Consider additional immunosuppressants and IVIG, particularly in dermatomyositis-like presentations 2
  • These treatments are commonly used for polymyositis/dermatomyositis, though efficacy in ICPi-induced myositis is not clearly documented 2

Special Considerations

• For scorpion sting-induced rhabdomyolysis with rash:

  • Over-the-counter acetaminophen and NSAIDs can be used for local pain 2
  • Topical lidocaine can relieve local pain if skin is intact 2
  • Ice can be useful for local pain relief 2

• For statin-induced rhabdomyolysis with rash:

  • Immediately discontinue the statin 2
  • Evaluate for statin-associated autoimmune myopathy (HMGCR antibodies, incomplete resolution) which requires additional therapy directed at the autoimmune process 2
  • Consider referral to a neurologist specializing in neuromuscular disorders 2

Monitoring and Follow-up

• Repeated bioassessment should include plasma myoglobin, CK, and electrolyte measurements 1
• Continue intravenous fluids until CK levels are lower than 1,000 U/L 3
• For immune-mediated causes, monitor with serial examinations including inflammatory markers every 4-6 weeks after treatment initiation 2
• Most patients require hospital admission for monitoring and management 5

Pitfalls and Caveats

• Delayed treatment of rhabdomyolysis is associated with higher risk of acute kidney injury 1, 6
• Bicarbonate and mannitol do not have strong evidence for improved outcomes, though bicarbonate may be considered for patients who are acidotic 5, 6, 3
• In immune-mediated myositis with rash, myocardial involvement can be fatal and requires urgent treatment 2
• Patients with concomitant myasthenia gravis and myocarditis have high mortality rates 2
• Avoid medications that can exacerbate rhabdomyolysis, particularly succinylcholine 1