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

Rhabdomyolysis Management

The treatment for rhabdomyolysis requires immediate aggressive intravenous fluid resuscitation with isotonic saline (0.9% NaCl) targeting a urine output of >300 mL/hour to prevent acute kidney injury. 1 This approach has reduced mortality from nearly 100% to less than 20% over the past decades in severe cases 2.

Immediate Management Steps

1. Fluid Resuscitation:

   • Begin with isotonic saline (0.9% NaCl) immediately
   • AVOID potassium-containing fluids like Lactated Ringer's which may worsen hyperkalemia 1
   • Target urine output >300 mL/hour 1, 3
   • Continue IV fluids until CK levels decrease to <1,000 U/L 4

2. Discontinue Causative Agents:

   • Immediately stop any medications that may cause or worsen rhabdomyolysis (statins, etc.) 1
   • Avoid all nephrotoxic medications (NSAIDs, diuretics, ACE inhibitors/ARBs) 1

3. Electrolyte Management:

   • Monitor and urgently correct hyperkalemia if present 1
   • Address hypocalcemia if symptomatic 1
   • Monitor phosphorus and magnesium levels 1

4. Monitoring Parameters:

   • Check CK levels every 6-12 hours in acute phase 1
   • Monitor electrolytes, renal function, and urine output frequently 1
   • Assess for metabolic acidosis with arterial blood gases 1

Diagnostic Criteria

• Serum CK typically at least 10 times the upper limit of normal 1, 5
• Plasma myoglobin confirms muscle breakdown (rises earlier than CK but has shorter half-life) 1
• Urinalysis showing myoglobinuria: positive for blood on dipstick but negative for RBCs on microscopy 1

Complications to Monitor and Manage

1. Acute Kidney Injury:

   • Most significant complication requiring nephrology consultation 1
   • Consider renal replacement therapy on a case-by-case basis 3

2. Electrolyte Abnormalities:

   • Hyperkalemia (life-threatening)
   • Hypocalcemia
   • Hyperphosphatemia
   • Metabolic acidosis

3. Compartment Syndrome:

   • Assess for pain, tension, paresthesia, and paresis 1
   • Measure compartment pressure if suspected (threshold >30 mmHg) 1
   • Requires decompressive fasciotomy if confirmed 4

4. Other Potential Complications:

   • Disseminated intravascular coagulation 3
   • Liver dysfunction 3

Controversial Treatments

• Bicarbonate: May be used for patients with acidosis, but evidence for improved outcomes is limited 3, 6
• Mannitol: Can be considered if urine output goals are not met despite adequate fluid resuscitation, but evidence for routine use is weak 3, 6
• Loop diuretics: Limited evidence for improved outcomes 3

Common Pitfalls and Caveats

• Delayed recognition: Rhabdomyolysis can present with non-specific symptoms; don't wait for the classic triad of myalgias, weakness, and dark urine (present in <10% of cases) 5
• Inadequate fluid resuscitation: Don't underestimate fluid requirements; aggressive hydration is crucial 2
• Delayed treatment: Don't wait for laboratory confirmation to begin fluid resuscitation in suspected cases 1
• Missing underlying causes: Investigate for genetic disorders in cases of recurrent rhabdomyolysis or positive family history 5
• Medication interactions: Be aware of drug combinations that increase rhabdomyolysis risk, such as statins with CYP3A4 inhibitors 1

Follow-up Care

• Follow-up with nephrology within 1-2 weeks 1
• Monitor for recurrence and maintain adequate hydration, especially during exercise 1
• Consider genetic testing in cases of recurrent rhabdomyolysis or suspected inherited disorders 1