To investigate clinical features and etiology of severe hand-foot and mouth disease(HFMD)children combined with acute flaccid paralysis(AFP).

This was a prospective observational study with institutional ethics approval and written parents of each child consent. A total of 32 children of severe HFMD with AFP in 2500 severe HFMD who hospitalized from April 2008 to July 2011 in Children's Hospital of Kunming were recruited.Lab tests including blood routine test, routine biochemical analysis, electrocardiogram, electroencephalogram, CT scan of the brain and examination of the cerebrospinal fluid(CSF) and so on, and stool samples collected from severe HFMD with AFP children were also processed for detection of etiological features and types.

The incidence rate of severe HFMD with AFP in severe HFMD was 1.3%(32/2500). All of 30 (93.8%) out of 32 cases of severe HFMD with AFP children were less than 3 years old, 27(87.1%) out of 31 cases were EV71RNA positive by tests of stool samples, early signs and symptoms of severe HFMD with AFP included fever, rashes on hands and feet, herpes of mouth, sores in the mouth, and a rash with blisters, severe neurological complications and tachypnea, electroencephalogram had slow mode wave, white blood cell (WBC) count and protein increased in CSF, WBC count and neutrophil increased significantly in blood routine test, all cases had encephalitis, encephalomyelitis, flaccid paralysis, pneumonedema and circulatory collapse etc.. Death of neurogenic pulmonary edema and pulmonary hemorrhage had 2 cases presenting in a critical condition during admission.

Severe HFMD with AFP occurred more often in children less than 3 years old, EV 71 was the major etiological agent.It was necessary to treatment by lucocorticoid and intravenous immunoglobulin as soon as possible, which could reduced complication and sequela of severe HFMD.