What is the management of rhabdomyolysis?

Management of Rhabdomyolysis

Immediately initiate aggressive intravenous fluid resuscitation with 0.9% normal saline at 1 liter per hour to prevent acute kidney injury, which is the most critical intervention for reducing mortality and preserving renal function. 1, 2

Immediate Fluid Resuscitation

• Start IV fluids at 1000 mL/hour of 0.9% normal saline immediately upon patient contact, establishing IV access in an accessible limb 2
• Target a urine output of 300 mL/hour once bladder catheterization is established—this is the therapeutic goal that drives all fluid management decisions 1, 2, 3
• For severe rhabdomyolysis (CK >15,000 IU/L), volumes greater than 6L per day may be required; for moderate cases, 3-6L per day is typically sufficient 1, 4
• Avoid potassium-containing fluids and starch-based fluids entirely 2
• Continue IV fluids until CK levels decrease below 1,000 U/L, urine output remains adequate, electrolytes normalize, and renal function stabilizes 2, 3

Electrolyte Monitoring and Management

• Monitor electrolytes (particularly potassium, calcium, and phosphorus) every 6-12 hours 1, 2
• Hyperkalemia is the most immediately life-threatening complication and can lead to cardiac arrhythmias and arrest—treat aggressively with standard protocols 1, 2
• Repeated bioassessment should include plasma myoglobin, CK, and potassium measurements 1
• Monitor for metabolic acidosis with arterial blood gas analysis in severe cases 1

Medication Review

• Immediately discontinue any offending agents, particularly statins, which are a common cause with an incidence of 1.6 per 100,000 patient-years 1
• Stop all dietary supplements associated with rhabdomyolysis risk, including red yeast rice (containing lovastatin), creatine monohydrate, wormwood oil, licorice, and Hydroxycut 1, 2
• Avoid succinylcholine in the perioperative setting as it can exacerbate rhabdomyolysis 1

Compartment Syndrome Surveillance

• Maintain high suspicion for compartment syndrome, which can both cause and complicate rhabdomyolysis 1, 4
• Early signs include pain, tension, paresthesia, and paresis—these are the window for intervention 1, 4
• Late signs (pulselessness and pallor) often indicate irreversible damage 1
• Perform early fasciotomy when compartment pressure exceeds 30 mmHg or when differential pressure (diastolic BP minus compartment pressure) is <30 mmHg 1, 4, 2

Renal Replacement Therapy Indications

• Initiate dialysis early for: refractory hyperkalemia, severe metabolic acidosis, fluid overload, or persistently elevated CK levels after 4 days of adequate hydration 2
• Acute kidney injury is the most significant complication and occurs particularly when CK exceeds 16,000 IU/L 5
• Myoglobinuric renal failure requiring dialysis is a potential delayed complication 1

Pain Management Algorithm

• First-line: Acetaminophen 500-1000 mg (onset 15-30 minutes, maximum 4-6 grams daily) as it avoids nephrotoxic effects 1
• Avoid all NSAIDs (ibuprofen, ketoprofen, diclofenac, naproxen, mefenamic acid) due to gastrointestinal and renal toxicity 1
• For severe pain unresponsive to acetaminophen: oral morphine 20-40 mg for opioid-naive patients 1
• If acute kidney injury develops with eGFR <30 mL/min: switch to fentanyl or buprenorphine as the safest opioid choices 1
• Provide round-the-clock dosing with rescue doses (10-15% of total daily dose) for breakthrough pain 1

Laboratory Workup

• CK level at least 10 times the upper limit of normal is diagnostic 3
• Complete blood count with differential to evaluate for infection or systemic processes 1
• Liver function tests (AST, ALT, alkaline phosphatase) as transaminitis commonly occurs due to muscle enzyme release 1
• Urinalysis showing brown color, cloudiness, and positive for blood without RBCs indicates myoglobinuria 1
• Coagulation studies to evaluate for disseminated intravascular coagulation in severe cases 1

Special Considerations for Recurrent or Unexplained Cases

• Consider genetic testing for RYR1 and CACNA1S gene sequencing (malignant hyperthermia susceptibility) in patients with exertional rhabdomyolysis or heat illness 1
• Test for metabolic myopathies (CPT2, PYGM, ACADM, AMPD1, VLCAD genes) in recurrent rhabdomyolysis 1
• Evaluate for SLCO1B1 gene mutations in statin-induced cases, as genetic factors increase risk 1
• Consider autoimmune markers (ANA, ASMA, ANCA) if autoimmune myositis is suspected 1

Admission Criteria

• Hospitalize patients with rhabdomyolysis who have immunocompromised state, significant pain requiring management, mental confusion, pulmonary infiltrates, abnormal spinal fluid findings, or specific organ failure 1
• Most patients require admission; discharge may be appropriate only for very mild cases with CK trending down and normal renal function 6

Common Pitfalls to Avoid

• Delayed fluid resuscitation is associated with higher risk of acute kidney injury—time is critical 1
• Do not wait for laboratory confirmation if clinical suspicion is high; start fluids immediately 2
• In trauma patients with simple contusion, CK elevation may peak 24-120 hours post-event without reflecting true rhabdomyolysis—repeat CK at 24 hours if clinical suspicion remains 1
• Mortality rate is approximately 10% overall but significantly higher in patients who develop acute renal failure 5