Exertional rhabdomyolysis: clinical features, management, complications and prediction of acute kidney injury.

OBJECTIVES

To describe the clinical course and complications of exertional rhabdomyolysis, compare inpatient and outpatient management, and evaluate admission markers of acute kidney injury (AKI).

METHODS

Prospective, multicentre study with consecutive inclusion of patients with rhabdomyolysis (creatine kinase (CK) ≥5000 U/L and/or myoglobin ≥1000 ng/mL) with exercise as the precipitating factor, presenting to the emergency departments of four hospitals in Oslo and Akershus, Norway (2019-2022). Management followed usual care. Primary outcome was AKI, defined by Kidney Disease: Improving Global Outcomes criteria.

RESULTS

We included 136 patients with exertional rhabdomyolysis (median age 28 years, 55% male), mainly after strength training (106, 78%); 62 (46%) were managed as inpatients and 74 (54%) as outpatients. Management was similar in both groups, consisting of fluids, serial blood tests, with a median follow-up of 3 days. Complications were rare and no outpatients required escalation to inpatient care. Five (4%) patients developed AKI (median peak creatinine 217 µmol/L, 132-410). Other major complications (severe electrolyte disturbances and compartment syndrome) occurred only in those with AKI.All patients who developed AKI had serum creatinine above the normal reference range at admission, though a few patients with elevated creatinine did not develop AKI (95% specificity). The myoglobin-to-CK ratio (≥0.48) performed best among muscle injury biomarkers and might serve as a supportive high-risk marker (99% specificity).

CONCLUSION

No patient with a normal admission creatinine developed AKI in this cohort, supporting outpatient management as a safe option for otherwise healthy individuals when admission creatinine is within the reference range, provided follow-up is ensured.

TRIAL REGISTRATION NUMBER: NCT04118608.