Influenza B-associated rhabdomyolysis in Taiwanese children.

AIM: Influenza B-associated rhabdomyolysis (IBAR) is an infrequent and little-known complication of influenza B virus infection in children. Diagnosis is usually made based on clinical history, the presence of influenza in the community and detection of virus in nasopharyngeal specimens. The aim of this study was to describe the clinical and laboratory manifestations, complications and outcomes of IBAR in Taiwanese children.

METHODS: A retrospective analysis was conducted in patients aged < 17 years who had been diagnosed with IBAR at a university children's hospital in North Taiwan during 2000-2007. All children enrolled in the study had presented with rhabdomyolysis associated with laboratory-confirmed influenza B infections. Demographic data, clinical manifestations, complications and outcomes were included in the analysis.

RESULTS: Overall, 24 IBAR cases were analysed. IBAR typically occurred in school-aged children with a 7:3 male:female ratio. The mean age was 7.2 ± 1.9 years. Nearly 63% of cases occurred between the ages of 6 and 9 years. The median interval between the onset of influenza and onset of IBAR was 3.4 days (range, 1-14). The calf muscles were involved in all cases. Laboratory tests indicated a mean initial blood creatine kinase of 4212 U/L. The median time to clinical recovery was 5 days (range 1-24). No patient had renal failure. IBAR tends to occur mainly in winter and spring during influenza B outbreaks. IBAR sometimes induces some complications, and early detection and careful medical treatment are necessary.

CONCLUSION: The results of this study indicate that outcomes of IBAR are good with proper medical care.