Unusual muscular injury in an infant with severe H1N1 infection.

We report the first well-documented case of unilateral orbital myositis in an 8-month-old boy with life-threatening pandemic H1N1 infection. He presented with status epilepticus and hemodynamic failure associated with unusual right orbital myositis and acute rhabdomyolysis. Because of severe myolysis, metabolic screening was performed to exclude metabolic and genetic etiologies. After corticosteroid administration and symptomatic support, the disease evolution was favorable, without sequelae at hospital discharge. H1N1 influenza infection may be associated with multiple organ failure, and complicated by unusual muscle injury. The presence of intense myolysis should alert practitioners to potential metabolic and genetic etiologies.