SHM Converge Scientific Abstract ePoster Gallery-A Rhabdo Roller Coaster: Delayed Diagnosis of McArdle Disease in a Patient With Recurrent Non-Traumatic Rhabdomyolysis

A Rhabdo Roller Coaster: Delayed Diagnosis of McArdle Disease in a Patient With Recurrent Non-Traumatic Rhabdomyolysis

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This case describes a delayed diagnosis of McArdle disease (glycogen storage disorder type V) in a teenager with recurrent, non-traumatic rhabdomyolysis. The patient had three hospital admissions between ages 15 and 17 for episodes of muscle pain, swelling, and dark urine. The episodes occurred after minimal or unusual triggers, including sleeping, riding a roller coaster, and moving furniture. During one episode, he developed forearm compartment syndrome requiring urgent fasciotomy. Labs during each admission were consistent with rhabdomyolysis.<br /><br />McArdle disease is caused by autosomal recessive mutations in the PYGM gene, leading to deficiency of glycogen phosphorylase. This impairs skeletal muscle energy production, especially during exertion, and results in abnormal glycogen accumulation within muscle fibers, muscle breakdown, and rhabdomyolysis. MRI findings can show muscle inflammation or fatty infiltration, and histopathology may demonstrate glycogen deposits that give muscle fibers a vacuolated appearance.<br /><br />After repeated admissions, the patient was ultimately diagnosed at age 17 through genetic testing, which identified two variants in the PYGM gene. The report emphasizes that clinicians should consider genetic and metabolic causes of myopathy when rhabdomyolysis occurs without a clear traumatic explanation. Earlier recognition of McArdle disease can reduce symptom severity, prevent repeat hospitalizations, and limit long-term complications.

Asset Subtitle

Marilee Schaner

Meta Tag

Author List Allison Ashford, Kelsey Hillyer, Marilee Schaner

Category Clinical Vignettes

Concept McArdle Disease

Concept Glycogen Phosphorylase

Concept Rhabdomyolysis

Concept PYGM Gene

Concept Exercise-Induced Muscle Breakdown

Distinguished Non-Finalist

Presenter Organization University of Nebraska Medical Center, Children's Nebraska

Presenting Author Marilee Schaner

Track Pediatric

Keywords

McArdle disease

glycogen storage disorder type V

recurrent rhabdomyolysis

PYGM gene

teenager

muscle pain

dark urine

compartment syndrome

genetic testing

metabolic myopathy

McArdle Disease

Glycogen Phosphorylase

Rhabdomyolysis

PYGM Gene

Exercise-Induced Muscle Breakdown