USMLE Prep - Medical Reference Library

Rhabdomyolysis — Early Aggressive Fluids, Electrolyte Management, and Renal Protection

System: Emergency Medicine • Reviewed: Sep 2, 2025 • Step 1Step 2Step 3

Synopsis:

Muscle injury with marked CK elevation leads to myoglobin-induced AKI and electrolyte disturbances. Initiate early aggressive isotonic fluids, monitor and treat hyperkalemia and hypocalcemia, and consider urine alkalinization selectively; identify and remove precipitating factors.

Key Points

  • Use the highest‑yield diagnostic test early; do not let testing delay time‑critical therapy.
  • Set objective targets and reassess frequently.
  • Plan definitive source control or disease‑specific therapy when indicated; document follow‑up and patient education.

Algorithm

  1. Identify rhabdomyolysis; start aggressive fluids and monitor urine output.
  2. Treat electrolytes (esp. K+); evaluate for compartment syndrome.
  3. Address causes (trauma, exertion, toxins, statins); plan disposition based on CK/renal function.

Clinical Synopsis & Reasoning

Muscle injury with marked CK elevation leads to myoglobin-induced AKI and electrolyte disturbances. Initiate early aggressive isotonic fluids, monitor and treat hyperkalemia and hypocalcemia, and consider urine alkalinization selectively; identify and remove precipitating factors.


Treatment Strategy & Disposition

Stabilize ABCs. Initiate guideline‑concordant first‑line therapy with precise dosing and continuous monitoring. Escalate to advanced/procedural interventions based on explicit failure criteria. Define ICU, step‑down, and ward disposition triggers; involve specialty teams early.


Epidemiology / Risk Factors

  • Risk varies by comorbidity and precipitants; see citations for condition‑specific data.

Investigations

TestRole / RationaleTypical FindingsNotes
Serum CK, electrolytes, creatinine, urinalysisDiagnosisCK often >5× ULN; heme-positive dipstick with few RBCsMonitor trends
EKG and telemetrySafetyDetect hyperkalemia-induced arrhythmias
Compartment pressure (if suspected)ComplicationCompartment syndromeSurgical eval

High-Risk & Disposition Triggers

TriggerWhy it mattersAction
CK >5000–10000 IU/L with rising creatinineAKI riskAggressive fluids; monitor K+; ICU if severe
Hyperkalemia/arrhythmiasLife-threateningStandard hyperkalemia protocol; telemetry
Compartment syndromeLimb threatSurgical eval
Toxin exposure (statins, cocaine)Recurrence riskStop offending agents; manage complications
Anuria or refractory acidosisDialysis indicationNephrology consult

Pharmacology

Medication/InterventionMechanismOnsetRole in TherapyLimitations
Isotonic fluids (e.g., LR/NS) 200–400 mL/h, titrate to urine output 200–300 mL/hRenal protectionHoursReduce AKI riskAvoid volume overload
Manage hyperkalemia per protocol; avoid routine calcium unless symptomaticElectrolytesMinutesPrevent arrhythmia
Urine alkalinization with bicarbonate (selected)AdjunctHoursMay reduce pigment nephropathyEvidence mixed

Prognosis / Complications

  • Outcome depends on timeliness of diagnosis and definitive therapy; monitor for complications.

Patient Education / Counseling

  • Provide red‑flag education, adherence guidance, and explicit return precautions; arrange timely specialty follow‑up.

References

  1. Rhabdomyolysis reviews and emergency nephrology guidance — Link