Benign Acute Childhood Myositis Associated with Influenza A (H1N1) Virus Infection: Evaluation of 22 Cases

We present the epidemiology, clinical features, and laboratory findings of 22 cases diagnosed with benign acute childhood myositis (BACM) after H1N1 infection in Konya, to observe and discuss this rare condition. This retrospective study was conducted in 22 children, diagnosed with BACM, who were brought to pediatric emergency department and pediatric rheumatology outpatient clinic of Selçuk University Medicine Faculty because of walking difficulties, between September 2017 and January 2018. Sixteen of the 22 (72.7%) patients enrolled in the study were male. The age of onset of symptoms ranged between 55 and 172 months. The interval between the onset of symptoms and the diagnosis was between 2 and 10 days. Throat pain was present in all cases as a prodromal symptom. Twelve (54.54%) of the cases presented with inability to stand or walk. Nine (40.90%) had gait abnormalities such as tip-toe walking, or a wide-based gait with a lordotic posture. Bilateral calf sensitivity was present in all cases. One patient had hypoactive deep tendon reflexes. In conclusion, although BACM is almost a typical clinical condition, we conclude that the recognition of the disease by family doctors and pediatricians is not sufficient and frequently underdiagnosed.