Objective: To determine the evolution of benign acute childhood myositis (BACM) in children and to assess the relationship between creatine phosphokinase (CPK) values and myoglobinuria. Study design: A retrospective study of patients with benign acute childhood myositis seen in two tertiary care university-affiliated pediatric hospitals during overlapping four-year periods. Methods: Demographic data, historical details, clinical and laboratory results were extracted from the charts of children 3 times normal. Complications, treatments and outcomes were recorded. Results: 54 children were included, 43 (80%) were male and mean age was 7.3 years (range 3-16 years, median 6 years), none showed abnormal neurological findings, manifested hematuria, or developed renal failure. Mean CPK level at presentation was 1872 IU/L (range 511 - 8086 IU/L). None developed renal failure and there were no adverse outcomes on follow up. Conclusions: Acute childhood myositis is a predominantly benign disease. Neurological examination is usually normal and rhabdomyolysis is rare. Although severe pathological co-morbid conditions must be excluded, a complete history and examination, coupled with simple blood and urine tests, can help minimize unnecessary diagnostic investigations.
