Clinical features, laboratory findings and differential diagnosis of benign acute childhood myositis.

We report clinical and laboratory data from 32 children with benign acute childhood myositis (BACM), children who presented with calf tenderness and gait abnormality. Laboratory evidence of a viral infection was evident in 23 patients, while serum creatine phosphokinase was uniformly increased (558 to 6800 U/L). Twenty-five patients (78.1%) were given a diagnosis other than BACM by their general practitioner or paediatrician. All patients made a rapid recovery within one week. We conclude that BACM should be encountered among the main causes of sudden-onset gait abnormality in young children.