To report a pediatric case of acute-onset anti-HMGCR myopathy in the setting of a recent EBV infection.
Anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (Anti-HMGCR) myopathy has historically been associated with statin exposure. It has also been seen in statin-naïve pediatric patients, though the etiology is unclear. Anti-HMGCR typically has a subacute onset and chronic progressive disease course. Here we present a pediatric case of anti-HMGCR myopathy with acute symptom onset during an EBV infection.
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A previously healthy 6-year-old Hispanic female presented with a three-week history of bilateral proximal limb weakness following an empiric ampicillin course for suspected strep pharyngitis. The patient presented to the ED after outpatient workup showed elevated AST/ALT (500s). Physical exam showed proximal symmetric weakness in the deltoids, biceps, triceps, hip flexors, and extensors, positive Gower's sign, and bilateral pelvic tilt with waddling gait. Serum testing showed elevated AST 455, ALT 653, and CPK of 18290. Workup was notable for elevated ANA and dsDNA autoantibodies, elevated TSH, and low vitamin D and complement. EBV panel showed elevated VCA IgG (525), early Ab IgG (44.9), and plasma qPCR (201). Given the elevated ANA and dsDNA, suspicion was greatest for myositis. EMG revealed evidence of irritative myositis. Serum antibody testing for myositis showed elevated anti-HMGCR Ab (>200; measured three weeks post-symptom onset). The patient showed improvement of motor strength after treatment with prednisolone and monthly IVIG therapy.
This case highlights an atypical pediatric presentation of acute-onset anti-HMGCR myopathy following in the setting of an EBV infection. Anti-HMGCR myopathy has been described in only one adult patient with EBV, but no pediatric patients. Expanding our understanding of this myopathy's etiology and presentation can lead to earlier detection and improve patient outcomes.