What is the primary treatment for a patient presenting with rhabdomyolysis, considering potential complications such as acute kidney injury and underlying health conditions like kidney disease?

Primary Treatment for Rhabdomyolysis

Aggressive intravenous fluid resuscitation with 0.9% normal saline is the cornerstone of rhabdomyolysis treatment, initiated immediately at 1 liter per hour to prevent acute kidney injury and reduce mortality. 1, 2, 3

Immediate Fluid Resuscitation Protocol

Start aggressive IV fluid resuscitation as soon as possible—even before patient extrication is complete in trauma cases—as delayed initiation significantly increases the risk of acute kidney injury. 1, 4, 2

Fluid Type and Rate

• Use 0.9% normal saline exclusively as the initial resuscitation fluid. 4, 2, 3
• Infuse at 1000 mL/hour during the initial phase. 1, 2
• Reduce infusion rate by at least 50% if resuscitation extends beyond 2 hours to avoid volume overload. 4, 2
• Avoid potassium-containing fluids (Lactated Ringer's, Hartmann's solution, Plasmalyte A) because potassium levels can increase markedly after reperfusion even with intact renal function. 4, 2
• Avoid starch-based fluids due to their association with increased rates of acute kidney injury. 4, 2

Volume Requirements Based on Severity

• For severe rhabdomyolysis (CK >15,000 IU/L): administer >6 liters per day. 1, 4
• For moderate rhabdomyolysis: administer 3-6 liters per day. 1, 4
• Early vigorous fluid resuscitation with ≥12 liters daily may be required in extensive traumatic rhabdomyolysis, particularly in young, carefully monitored patients. 5

Target Urine Output

Achieve and maintain a urine output of ≥300 mL/hour (approximately 3-5 mL/kg/hour for a 70 kg patient), which is 6-10 times higher than standard oliguria thresholds. 4, 2, 6

• Insert a bladder catheter immediately to monitor hourly urine output unless urethral injury is suspected. 4, 2
• This high urine output target ensures adequate myoglobin clearance and prevents tubular precipitation. 4

Critical Electrolyte Management

Monitor potassium, calcium, and phosphorus every 6-12 hours in severe cases, as hyperkalemia can precipitate life-threatening cardiac arrhythmias. 1, 2

• Treat hyperkalemia aggressively with standard protocols including calcium gluconate for cardiac membrane stabilization, insulin with dextrose, and beta-agonists. 2
• Monitor for hypocalcemia but avoid calcium replacement unless symptomatic or severe, as calcium can precipitate in damaged muscle tissue. 1

What NOT to Use Routinely

Bicarbonate

Do not routinely use sodium bicarbonate for urinary alkalinization, as current evidence shows no benefit over aggressive crystalloid resuscitation alone. 4, 3

• Bicarbonate is reserved only for severe metabolic acidosis or life-threatening hyperkalemia as a general critical care principle. 4
• Large doses of bicarbonate can worsen hypocalcemia by decreasing free calcium levels. 4

Mannitol

Do not routinely use mannitol, as studies show little additional benefit compared to crystalloid resuscitation alone and it is potentially nephrotoxic. 4, 3

• Mannitol may only benefit patients with markedly elevated CK (>30,000 U/L), though even this benefit remains undefined, and it is contraindicated in patients with oligoanuria. 4

Diuretics

Diuretics are generally not recommended as primary treatment and may increase the risk of acute kidney injury unless adequate volume resuscitation has first been achieved. 4

• Consider diuretics only after adequate volume expansion for management of volume overload, not as primary rhabdomyolysis treatment. 4

Laboratory Monitoring

Measure total creatine kinase (CK), not CK-MB, as the diagnostic standard for rhabdomyolysis. 1

• Perform repeated bio-assessments of plasma myoglobin, CK, and potassium levels. 1, 4
• Monitor CK, creatinine, potassium, calcium, and phosphorus every 6-12 hours in severe cases. 4, 2
• CK levels peak 24-120 hours after the inciting event, so initial levels may not represent the peak. 1

Medication Review

Immediately discontinue any causative agents, particularly statins, which are the most common drug cause of rhabdomyolysis. 1, 2

• Stop supplements including red yeast rice containing lovastatin, creatine monohydrate, wormwood oil, licorice, and Hydroxycut. 1, 2

Duration of Treatment

Continue intravenous fluids until CK levels decrease below 1,000 U/L, urine output remains adequate, electrolytes normalize, and renal function stabilizes or improves. 2, 6

Indications for Renal Replacement Therapy

Initiate dialysis emergently for: 7, 2

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

Use intermittent hemodialysis as the preferred modality, as it provides rapid clearance of potassium and allows treatment of multiple patients per day on the same machine. 4

Compartment Syndrome Surveillance

Maintain high suspicion for compartment syndrome, which can both cause and complicate rhabdomyolysis. 1

• Early signs include pain, tension, paresthesia, and paresis; late signs (pulselessness and pallor) indicate irreversible damage. 1
• Perform early fasciotomy when compartment pressure exceeds 30 mmHg or differential pressure (diastolic BP minus compartment pressure) is <30 mmHg. 1, 2

Common Pitfalls to Avoid

• Do not delay fluid resuscitation waiting for laboratory confirmation—start immediately based on clinical suspicion. 1, 4
• Do not use the 1.5 mg/dL creatinine threshold as a trigger for intervention, as this is specific to cirrhotic patients with AKI and not applicable to rhabdomyolysis. 1
• Do not assume impact trauma alone explains CK elevation—assume true muscle breakdown until proven otherwise if CK is trending upward. 1
• Avoid excessive fluid administration in patients with cardiac or renal compromise without careful monitoring, as this can cause fluid overload. 4