How should rhabdomyolysis be managed in the emergency setting?

Emergency Management of Rhabdomyolysis

Initiate aggressive intravenous fluid resuscitation with 0.9% normal saline at 1 liter per hour immediately upon patient contact, targeting a urine output of at least 300 mL/hour, as this is the single most critical intervention to prevent acute kidney injury and reduce mortality. 1, 2

Immediate Fluid Resuscitation Protocol

Initial Fluid Administration

• Establish IV access as soon as possible and begin 0.9% normal saline at 1000 mL/hour during the initial phase. 3, 1, 2
• If extrication or initial resuscitation extends beyond 2 hours, reduce the infusion rate by at least 50% (to ≥500 mL/hour) to prevent volume overload. 3, 1
• For severe rhabdomyolysis (CK >15,000 U/L or >30,000 U/L), administer >6 liters of IV fluids per day. 1, 4
• For moderate rhabdomyolysis, administer 3-6 liters of IV fluids per day. 1, 4

Fluid Type Selection

• Use isotonic saline (0.9% NaCl) exclusively as the primary crystalloid. 3, 1, 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. 3, 1, 2
• Avoid starch-based colloids due to their association with higher rates of acute kidney injury and bleeding complications. 3, 1, 2

Monitoring and Target Parameters

Urine Output Goals

• Insert a bladder catheter immediately (unless urethral injury is suspected) to monitor hourly urine output. 3, 1, 2
• Target 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. 1, 5, 6

Laboratory Monitoring

• Monitor CK, creatinine, potassium, calcium, and phosphorus every 6-12 hours in severe cases. 1, 2, 4
• Continue IV fluids until CK levels decrease below 1,000 U/L, urine output remains adequate, electrolytes normalize, and renal function stabilizes. 2, 5
• Use point-of-care analyzers (e.g., iStat) if conventional laboratory services are unavailable, noting they require ambient temperature of 16-30°C for accurate operation. 1

Electrolyte Management

Hyperkalemia

• Monitor potassium levels closely and treat hyperkalemia emergently with standard protocols (calcium gluconate, insulin/dextrose, albuterol) as it can precipitate life-threatening cardiac arrhythmias. 2, 4, 5
• Hyperkalemia is the most immediate life-threatening complication requiring aggressive management. 3, 7

Calcium and Phosphorus

• Monitor calcium levels but do not routinely supplement calcium during the oliguric phase, as hypercalcemia can develop during the recovery phase. 5, 8
• Expect hyperphosphatemia and hypocalcemia in the acute phase. 7, 8

What NOT to Use: Evidence-Based Contraindications

Urinary Alkalinization with Bicarbonate

• Do not routinely use sodium bicarbonate for urinary alkalinization, as current evidence shows no benefit over aggressive saline resuscitation alone for preventing pigment nephropathy. 1
• Large bicarbonate doses can worsen hypocalcemia by decreasing ionized calcium levels. 1
• Reserve bicarbonate only for life-threatening hyperkalemia or severe metabolic acidosis (pH <7.1), using standard critical care dosing. 1, 2

Mannitol

• Do not routinely use mannitol, as studies demonstrate minimal additional benefit over crystalloid resuscitation and potential nephrotoxicity. 1, 2
• Mannitol may only benefit patients with CK >30,000 U/L, but this benefit remains undefined and is contraindicated in oligoanuric patients. 1

Diuretics

• Diuretics are not recommended as primary treatment and should only be considered after adequate volume expansion for management of volume overload, not for myoglobin clearance. 1
• Loop diuretics may increase risk of acute kidney injury unless adequate volume resuscitation has been achieved first. 1, 9

Renal Replacement Therapy Indications

Initiate dialysis for the following absolute indications: 3, 2

• Refractory hyperkalemia unresponsive to medical management
• Severe metabolic acidosis
• Volume overload despite conservative management (pulmonary edema)
• Uremic symptoms (encephalopathy, pericarditis)
• Persistently elevated CK after 4 days of adequate hydration

RRT Modality Selection

• Intermittent hemodialysis is the preferred modality, providing rapid potassium clearance and ability to treat multiple patients per day on the same machine. 3, 1
• Deliver a Kt/V of at least 1.2 per treatment, 3 times per week when using intermittent RRT. 3
• One or more dialysis treatments per day may be required due to the hypercatabolic state. 3
• Continuous RRT (20-25 mL/kg/hour effluent volume) is appropriate in hemodynamically unstable patients but requires 24/7 nursing care. 3

Compartment Syndrome Recognition and Management

Clinical Diagnosis

• Suspect compartment syndrome based on the "6 Ps": pain, paresthesia, paresis, pain with stretch, pink skin color, and late findings of pulselessness and pallor. 3, 4
• Pulselessness and pallor indicate arterial occlusion and represent late diagnosis with poor outcomes. 3

Intervention Thresholds

• Perform fasciotomy when compartment pressure exceeds 30 mmHg or when differential pressure (diastolic BP minus compartment pressure) is <30 mmHg. 2, 4
• In hypotensive patients, fasciotomy is indicated when intracompartment pressure ≥20 mmHg. 3
• Remove tight dressings, split casts, and avoid limb elevation as initial measures. 3

Medication Review and Discontinuation

Immediately discontinue the following causative agents: 2, 4

• Statins (most common drug cause, incidence 1.6 per 100,000 patient-years)
• Red yeast rice containing lovastatin
• Creatine monohydrate supplements
• Wormwood oil, licorice, Hydroxycut
• Any medications with CYP3A4 interactions in statin users

Common Pitfalls to Avoid

• Delayed fluid resuscitation is associated with significantly higher risk of acute kidney injury—start fluids immediately, even before complete diagnostic workup. 1, 2
• Failure to achieve target urine output of 300 mL/hour leads to inadequate myoglobin clearance and tubular precipitation. 1, 5
• Using potassium-containing fluids can exacerbate life-threatening hyperkalemia. 3, 1
• Excessive fluid administration in patients with cardiac or renal compromise can cause pulmonary edema—monitor volume status carefully. 1
• Missing compartment syndrome diagnosis leads to nonviable limbs requiring amputation and worsens rhabdomyolysis. 3, 4
• CK levels peak 24-120 hours after the inciting event, so a single normal or mildly elevated CK does not exclude evolving rhabdomyolysis—repeat testing at 24 hours if clinical suspicion remains high. 4, 6