Nelarabine-associated rhabdomyolysis with severe creatine kinase elevation in a pediatric patient with T-cell acute lymphoblastic leukemia: a case report.

Nelarabine is a purine nucleoside analog used in relapsed or refractory T-cell acute lymphoblastic leukemia (T-ALL) and in up-front pediatric therapy. Although neurologic toxicity is dose-limiting, skeletal muscle toxicity, including rhabdomyolysis, has been reported. Rhabdomyolysis occurred in approximately 2% of nelarabine-treated patients in pediatric COG AALL0434, although the clinical features of these events were not detailed. We report a 7-year-old patient with T-ALL who developed rapidly progressive diffuse myalgia, muscle stiffness, impaired ambulation, dark urine, presumptive myoglobinuria, and a peak creatine kinase (CK) level exceeding 70,000 U/L shortly after nelarabine administration during consolidation. Nelarabine was discontinued, and aggressive intravenous hydration led to complete clinical and biochemical recovery without acute kidney injury or renal replacement therapy. This case provides a detailed pediatric description of clinically overt nelarabine-associated rhabdomyolysis and emphasizes early recognition, renal-protective management, and CK monitoring in symptomatic patients.