What is the initial management of suspected rhabdomyolysis (Rhabdo)?

Initial Management of Suspected Rhabdomyolysis

The initial management of suspected rhabdomyolysis should focus on aggressive fluid resuscitation with isotonic saline at 200-300 mL/hour until creatine kinase (CK) levels decrease to <1,000 U/L, with close monitoring of electrolytes, renal function, and urine output every 12-24 hours. 1

Diagnostic Approach

• Confirm diagnosis with serum creatine kinase (CK) levels - significantly elevated levels (typically >5 times upper limit of normal) suggest rhabdomyolysis 2
• Obtain baseline laboratory studies:
  • Complete metabolic panel (especially BUN, creatinine, electrolytes)
  • Urinalysis (check for myoglobinuria - tea/cola colored urine)
  • Serum potassium (critical to identify hyperkalemia)
  • Calcium, phosphorus levels
  • Arterial blood gas (if metabolic acidosis suspected)

Immediate Management Protocol

1. Fluid Resuscitation (Highest Priority)

• Begin immediate, aggressive IV fluid resuscitation with isotonic saline at 200-300 mL/hour 1
• Target urine output of 200-300 mL/hour (1-2 mL/kg/hr) 3
• Continue fluid resuscitation until CK levels decrease to <1,000 U/L 1
• Early vigorous fluid resuscitation with ≥12 L daily has been shown to reduce mortality from nearly 100% to <20% in severe cases 3

2. Electrolyte Management

• Monitor and correct electrolyte abnormalities, particularly:
  • Hyperkalemia (life-threatening): Obtain ECG and treat promptly if >6.0 mEq/L 1
  • Early hypocalcemia: Monitor but generally don't supplement unless symptomatic 4
  • Hyperphosphatemia: Monitor and treat if severe 4

3. Acid-Base Balance

• Consider urine alkalinization with sodium bicarbonate if severe acidosis present (pH <7.1) 1, 4
• While animal studies suggest benefit of urine alkalinization, high-quality human evidence is lacking 5

4. Monitoring Parameters (Every 12-24 hours)

• Serum CK levels
• Renal function (BUN, creatinine)
• Electrolytes
• Urine output
• Compartment pressures if extremity swelling present 4

Indications for Nephrology Referral/Dialysis

• Persistent hyperkalemia (>6.0 mEq/L) unresponsive to treatment
• Severe metabolic acidosis (pH <7.1)
• Volume overload
• Uremic symptoms
• Rapidly rising BUN/creatinine levels 1

Complications to Monitor

• Acute kidney injury (most common serious complication)
• Compartment syndrome (monitor intra-compartmental pressure, consider fasciotomy)
• Disseminated intravascular coagulation
• Cardiac arrhythmias from electrolyte disturbances 4

Common Pitfalls and Caveats

• Underestimating fluid requirements: Inadequate fluid resuscitation is a common error
• Delayed recognition: Consider rhabdomyolysis in patients with risk factors (intoxication, immobilization, altered mental status)
• Overemphasis on urine alkalinization: While commonly recommended, evidence for bicarbonate therapy is limited compared to the clear benefit of aggressive fluid resuscitation 5
• Failure to monitor for compartment syndrome: Can lead to permanent muscle damage and disability
• Missing underlying causes: Always identify and address the underlying cause of rhabdomyolysis

The prognosis is generally good when diagnosed early and treated promptly with aggressive fluid resuscitation, which remains the cornerstone of therapy 4.