Abstract: SA-PO0334
Sweat, Sugars, Storage, and Struggles Stretching Strings: Exertional Rhabdomyolysis in a Heterozygous Carrier of McArdle Disease
Session Information
- AKI: Case Reports - Drug/Toxin Injury, Crystals, Obstruction, and Unusual Presentations
October 24, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 102 AKI: Clinical, Outcomes, and Trials
Authors
- D'Souza, Ashton, Rochester General Hospital, Rochester, New York, United States
- Hix, John Kevin, Rochester General Hospital, Rochester, New York, United States
Introduction
McArdle disease is an autosomal recessive glycogen storage disorder caused by deficiency of muscle glycogen phosphorylase, typically presenting with exercise intolerance, myalgia, cramps, and, in severe cases, rhabdomyolysis. We report a unique case of exertional rhabdomyolysis in a heterozygous carrier of McArdle disease.
Case Description
34-year-old man with no significant past medical history, employed as a tree surgeon, presented with recurrent exertional rhabdomyolysis triggered by prolonged, strenuous physical activity in demanding environmental conditions. Patient described fatigue, muscle cramping, and dark urine despite adequate fluid intake. His symptoms were not associated with trauma and primarily related to progressive exertional intolerance making it difficult for him to work. He was hospitalized twice for rhabdomyolysis, with initial serum creatine kinase levels ranging from 768-944 units/L. On one occasion, rhabdomyolysis was complicated by transient acute kidney injury, with a serum creatinine of 2.7 mg/dL, that resolved after fluid resuscitation within 24 hours. However, baseline renal function was preserved between episodes without evidence of tubular injury, proteinuria, or chronic kidney disease. In the absence of a clear etiology for his presentations, genetic testing was done which identified a heterozygous PYGM mutation, suggesting a manifesting carrier state rather than classic biallelic McArdle disease. Dietary modification with frequent carbohydrate intake and magnesium supplementation resulted in symptomatic improvement and prevention of further episodes.
Discussion
The patient's physically demanding occupation characterized by prolonged isometric exertion in extreme environmental conditions likely contributed to symptom manifestation. Although carriers are usually asymptomatic, this case highlights the potential for clinically significant manifestations in heterozygous carriers of McArdle disease under significant physiologic stress. It also underscores the importance of considering genetic predisposition and metabolic myopathy in recurrent exertional rhabdomyolysis and suggests a role for gene-environment interactions in disease expression.