[Benign acute childhood myositis (BACM)--cases report].

Benign acute childhood myositis (BACM) is characterised by sudden calf pain and inability to walk. We analyzed the characteristics of seven boys and two girls with BACM treated in the Pediatric Department from April 2005 to March 2009. The mean age at onset of symptoms was 7 +/- 2 years. Two boys were hospitalized twice for BACM. All cases occurred in winter or spring. 7 out of all admissions were clustered together in one week long periods. Patients demonstrated prodromal symptoms of flu-like illness followed by the sudden onset of difficulty in walking. One girl additionally complained of a painful right hip. Four patients received inosine pranobex for prodromal viral infection before the clinical onset of myositis. In all cases, creatine phosphokinase (CPK; the highest value at 8988 U/l) and aspartate aminotransferase (AST; the highest value at 329 U/l) values were elevated. The serum concentration of myoglobin was elevated in five out of six tested patients (the highest value at 2172 microg/l). The following haematological abnormalities were detected: leucocytopenia (the lowest WBC 1.35 x 10(3)/microl), neutropenia, and trombocytopenia. All patients made a rapid recovery within 1 to 5 days. Pediatricians and emergency medicine specialists must be aware that BACM is a self-limiting disorder with the acute onset of inability to walk, elevated CPK and AST levels, and transient haematological abnormalities. There is no sufficient data from clinical reports on immunostimulant use before the onset of BACM.