Post-infectious fatigue syndrome in dengue infection.

BACKGROUND: Although the acute manifestations of dengue are well known, few studies have assessed the long-term consequences of dengue infection. We prospectively studied the incidence and factors associated with fatigue in a cohort of patients following dengue infection. METHODS: We included patients with serologically confirmed dengue infection admitted to the National University Hospital, Singapore, during a dengue outbreak from October-November 2005. The severity of dengue was graded as dengue fever, dengue haemorrhagic fever and dengue shock syndrome. A follow-up telephone interview was performed two months following hospital discharge, where a Fatigue Questionnaire was administered. The presence of significant fatigue was considered as the main outcome measure. Significance was assessed at P<0.05. RESULTS: One hundred twenty-seven patients, 71 (55.9%) males and 56 (44.1%) females, of mean age 36.06 years (range, 16-70; S.D., 13.722), participated in this study. Twenty-five (19.7%) patients had dengue haemorrhagic fever and the remaining 102 (80.3%) had dengue fever. In multivariate analysis, increased age, female sex, the presence of chills, and the absence of rashes were significantly associated with the development of fatigue post-dengue infection. There was no significant association between fatigue and dengue severity. CONCLUSIONS: This observation represents the first systematic evidence that dengue can result in clinical disease beyond the acute phases of infection. Host factors, such as age and sex may be important in the pathogenesis of this clinical entity.