OBJECTIVETo retrospectively analyzed the clinical features and epidemiology of children with severe hand-foot-and-mouth disease during 2009 and 2010 in Shanghai to investigate some risk factors with fatal cases.

METHODAll the clinical records and laboratory results of serious patients were collected. A retrospective study was performed.

RESULTA total of 748 serious patients were enrolled into this study, and the ratio of male to female was about 1.7:1; 724 patients were categorized into stage 2 with 254 patients in 2009 and 470 in 2010; 24 patients were categorized into stage 3 with 17 in 2009 and 7 in 2010. The rate of severity in 2010 (1.5%) was lower than in 2009 (6.3%) (χ2=12.836, P<0.01). Seven patients of stage 3 died, with the fatality 29.2%, which was higher than in stage 2 (P<0.01). The children aged between 3 months 10 days to 12 years 9 months with onset median age of 25 months. Among them, 77.1% patients aged between 1 and 4 years which also accounted for 79.2% of the fatal cases (19/24). But there was no significant difference between the age and the severity (χ2=0.804, P>0.05). Fever (100%), vomiting (57.0%) and myoclonus jerk (62.3%) were the most frequent symptoms occurred in those serious cases. The average period of fever in children of stage 2 and 3 was (4.10±1.40) d and (5.05±1.05) d, respectively, which indicated significant difference between the two groups (t=3.173, P<0.05). The average values of white-blood-cell counts and blood glucose in fatal patients were (14.8±6.25)×10(9)/L and (8.63±3.51) mmol/L. They were higher when compared to those in stage 2 with the white-blood-cell counts of (11.8±4.23)×10(9)/L and blood glucose of (5.51±2.14) mmol/L (P<0.05). But there was no significant difference in C-reactive protein or cerebrospinal fluid white-blood-cell counts; A total of 182 patients were enrolled for MRI study during the acute stage with 37 (37/182, 20.3%) presented abnormal findings. Among them, most frequent findings were hyperintense lesions seen in brain stem (11 cases). A stage 3 case who died presented brain edema on MRI examination.

CONCLUSIONThe epidemic of HFMD has some correlation with the area, season, health condition of the family and gender of the children. Children under 4 years of age especially those who lived in rural areas were susceptible to the HFMD. Frequent vomiting or myoclonus jerk may indicate the central nervous system involvement. But persistent high fever may indicate tendency to deteriorate. Some laboratory examinations can help find the fatal cases at an early time.