Viral myositis

A rare acquired skeletal muscle disease characterized by sudden onset of muscle weakness, tenderness, and pain during or following recovery from a viral illness. The most commonly reported underlying viral infections are influenza B and A, the latter being the significantly less frequent cause. Most cases occur in children. Symptoms are often limited to the calf muscles, but other muscle groups may be involved as well. The condition is typically self-limiting, resolving within several days, although rhabdomyolysis with renal failure and compartment syndrome have been reported.