Feel the Burn: An Evidence Based Approach to Rhabdomyolysis

Rhabdomyolysis is skeletal muscle necrosis that can rapidly progress to acute kidney injury, especially after trauma, crush injury, ischemia-reperfusion, or extreme exertion. Diagnosis hinges on the right clinical context plus a characteristic lab pattern, and early management is primarily thoughtful fluid resuscitation rather than bicarbonate or dialysis by default.

Recognizing Rhabdomyolysis Early

• High risk patient groups: Suspect rhabdomyolysis after crush injury, major muscle trauma, vascular compromise with reperfusion, or metabolic stressors such as strenuous exercise, toxins, infections, and inherited myopathies.
• Classic bedside features: Muscle pain, weakness, swelling, and tea-colored urine are the classic clues, but the bigger pearl is a low threshold for testing when the history fits, especially in older patients with limited reserve.
• Core laboratory pattern: Creatine kinase above 5 times the upper limit of normal or above 1000 IU/L supports the diagnosis, often alongside rising creatinine, hyperkalemia, elevated AST, LDH, and urine myoglobin.
• CK trend timing: CK usually peaks at 24 to 72 hours, so serial values matter more than a single number. We get into the practical timing for when trending adds value in the episode.

AKI Prevention And Complications

• Primary management target: Acute kidney injury is the complication to prevent first, and initial treatment centers on isotonic crystalloid with Lactated Ringer's or saline rather than reflex adjuncts.
• Fluid strategy basics: A starting infusion rate around 400 mL per hour is a reasonable anchor, with resuscitation titrated to urine output and often measured with a Foley for accuracy.
• Bicarb and diuretic limits: Despite common teaching, current evidence does not support bicarbonate or diuretics for routine prevention or treatment of rhabdomyolysis-associated AKI, a nuance we unpack in the chapter.
• Electrolyte danger zone: Hyperkalemia is the electrolyte abnormality that can kill early through dysrhythmia, while hyperphosphatemia and hypocalcemia also demand careful, complication-aware management.
• Dialysis decision point: Renal replacement therapy has no proven role in preventing AKI in rhabdomyolysis; use it for standard AKI indications based on renal impairment and the overall clinical picture.
• Complication surveillance: AKI is the most common systemic complication, but early and late morbidity also includes fluid overload, hepatic or cardiac dysfunction, DIC, and compartment syndrome.

Risk Stratification And Prognosis

• McMahon score role: The McMahon score uses admission demographics and routine labs to predict risk better than CK alone, particularly for renal replacement therapy and severe outcomes.
• Meaningful prognostic cutoff: A McMahon score of 6 or higher marks a higher-risk patient, though the score is more useful for prognosis than for dictating a completely separate treatment pathway.
• Limits of CK alone: CK helps confirm muscle injury, but it is less specific than the McMahon score for forecasting who will progress to dialysis-level kidney failure.
• Guideline anchored approach: The AAST consensus gives a practical framework for diagnosis, fluid choice, electrolyte management, and when prognostic tools help without overcalling their bedside authority.

References:  

1. Kodadek L, Carmichael Ii SP, Seshadri A, et al. Rhabdomyolysis: an American Association for the Surgery of Trauma Critical Care Committee Clinical Consensus Document. Trauma Surg Acute Care Open. 2022;7(1):e000836. Published 2022 Jan 27. PMID: 35136842