What is the treatment for a patient with suspected Rhabdomyolysis?

Treatment of Rhabdomyolysis

Immediately initiate aggressive intravenous fluid resuscitation with 0.9% normal saline at 1 liter per hour to prevent acute kidney injury and reduce mortality. 1

Immediate Fluid Resuscitation

Start IV fluids as early as possible—even before patient extrication is complete—as delayed initiation significantly increases the risk of acute kidney injury. 2, 1

• Establish IV access and infuse 0.9% normal saline at 1000 mL/hour during the initial phase 1
• Reduce infusion rate by at least 50% if initial resuscitation exceeds 2 hours to avoid volume overload 1
• Target urine output of ≥300 mL/hour (approximately 3-5 mL/kg/hour for a 70 kg patient—6-10 times higher than standard oliguria thresholds) to ensure adequate myoglobin clearance 3
• Insert bladder catheter to monitor hourly urine output unless urethral injury is suspected 1, 3

Fluid Volume Requirements Based on Severity

• Severe rhabdomyolysis (CK >15,000 IU/L): Administer >6L of IV fluids per day 2, 3
• Moderate rhabdomyolysis: Administer 3-6L of IV fluids per day 2, 3
• Continue IV fluids until CK levels decrease, urine output remains adequate, electrolytes normalize, and renal function stabilizes 1

Fluid Type Selection

Use isotonic saline (0.9% NaCl) exclusively for initial volume expansion. 3

• Avoid potassium-containing fluids (Lactated Ringer's, Hartmann's solution, Plasmalyte A) as potassium levels can increase markedly after reperfusion even with intact renal function 1, 3
• Avoid starch-based fluids due to association with increased acute kidney injury and bleeding 1, 3
• After initial resuscitation, fluid choice depends on hydration status and serum electrolyte levels 3

Interventions NOT Recommended

Do not routinely use urinary alkalinization with bicarbonate—current evidence shows no benefit over aggressive crystalloid resuscitation alone. 3

• Bicarbonate can worsen hypocalcemia by decreasing free calcium levels 3
• Large bicarbonate doses add extra volume without proven benefit 3

Do not routinely use mannitol—studies show little additional benefit compared to crystalloid resuscitation alone and it is potentially nephrotoxic. 3

• Mannitol may only benefit patients with markedly elevated CK (>30,000 U/L), though this benefit remains undefined 3
• Mannitol is contraindicated in patients with oligoanuria 3

Diuretics should not be used as primary treatment and only considered after adequate volume expansion for management of volume overload, not as primary rhabdomyolysis treatment. 3

Electrolyte Monitoring and Management

Monitor electrolytes (potassium, calcium, phosphorus) every 6-12 hours and treat hyperkalemia aggressively as it can precipitate life-threatening cardiac arrhythmias. 2, 1

• Perform repeated bioassessments of plasma myoglobin, CK, and potassium 2, 3
• Obtain ECG to identify life-threatening complications of hyperkalemia 4
• Trend CK, creatinine, and electrolytes daily until CK is declining and renal function is stable 2

Medication Review

Immediately discontinue any causative agents, particularly statins, which are a common cause of drug-induced rhabdomyolysis. 2

• Stop statins (especially simvastatin 80 mg), red yeast rice containing lovastatin, creatine monohydrate, wormwood oil, licorice, and Hydroxycut 2, 1
• Avoid medications that increase rhabdomyolysis risk, particularly statins metabolized by CYP3A4 2

Pain Management

Use acetaminophen 500-1000 mg as the preferred initial analgesic (maximum 4-6 grams daily) to avoid nephrotoxic effects of NSAIDs. 2

• Avoid all NSAIDs (ibuprofen, ketoprofen, diclofenac, naproxen, mefenamic acid) due to gastrointestinal and renal toxicity 2
• Reserve opioids for severe muscle pain unresponsive to acetaminophen 2
• For severe pain, use oral morphine 20-40 mg for opioid-naive patients 2
• In patients with established AKI (eGFR <30 mL/min), use fentanyl or buprenorphine as safest opioid choices 2

Compartment Syndrome Monitoring

Maintain high suspicion for compartment syndrome and perform early fasciotomy when compartment pressure exceeds 30 mmHg or differential pressure (diastolic BP – compartment pressure) is <30 mmHg. 2, 1

• Early signs include pain, tension, paresthesia, and paresis 2
• Late signs (pulselessness, pallor) often indicate irreversible damage 2

Renal Replacement Therapy Indications

Initiate dialysis early for: 1, 3

• Refractory hyperkalemia
• Severe metabolic acidosis
• Fluid overload despite conservative management
• Persistently elevated CK levels after 4 days of adequate hydration

Intermittent hemodialysis is the preferred modality as it provides rapid potassium clearance and allows treatment of multiple patients per day on the same machine 3

Laboratory Monitoring

Essential initial tests include: 2

• Complete blood count with differential
• Complete electrolyte panel (potassium, calcium, phosphorus, magnesium)
• CK, creatinine, urinalysis for myoglobinuria
• Liver function tests (AST, ALT, alkaline phosphatase)
• Coagulation studies to evaluate for disseminated intravascular coagulation

Monitor urine pH (target approximately 6.5) and ensure adequate kidney perfusion through urine output monitoring. 3

Common Pitfalls to Avoid

• Do not wait for CK to peak before initiating treatment—CK levels peak 24-120 hours after the inciting event, and current levels may not represent the peak 2
• Do not use the 1.5 mg/dL creatinine threshold as a trigger for intervention—this threshold is specific to cirrhotic patients with AKI and not applicable to trauma-related rhabdomyolysis 3
• Do not assume simple contusion—impact trauma can elevate CK without true rhabdomyolysis, but given rising trends, assume true muscle breakdown until proven otherwise 2
• Excessive fluid administration in patients with cardiac or renal compromise can cause fluid overload 3