Hypocoagulability in Severe Yellow Fever Infection is Associated with Bleeding: Results from a Cohort Study

BackgroundSevere Yellow fever infection (YFI) may be complicated by a hemorrhagic diathesis. However, the haemostasis profile of YFI has rarely been reported. The aim of this study was to characterize the haemostatic features of YFI by using a rotational thromboelastometry (ROTEM).MethodsWe evaluated clinical, laboratory and ROTEM parameters in adults with severe YFI, and their correlation with hemostatic variables according to bleeding and death.FindingsA total of 35 patients were included (median age 49 years). ROTEM was performed in 22 patients, of whom 21 (96%) presented bleeding and 4 (18%) died. All patients who died had major bleeding. Patients who died presented prolonged clotting time (CT; median 2,326; interquartile range [IQR], 1,898-2,986) and reduced alpha angle (median 12; IQR, 12-15) in comparison with patients who had minor (median CT 644; IQR, 552-845 and alpha angle 47; IQR, 28-65) and major (median CT 719; IQR, 368-1,114 and alpha angle 43; IQR, 32-64) bleeding and survived. In patients who bled, CT showed a strong negative correlation with factors(F) V (r = -0.68), IX (r = -0.84) and X (r = -0.63) as well as alpha angle with FIX (r = -0.92). In patients who died, the correlations were even stronger. A total of 19/21 (90%) patients presented hypocoagulability assessed by ROTEM.InterpretationHypocoagulabitity is the hallmark of the bleeding diathesis of severe YFI. Abnormal CT and alpha angle associated with death and could be used as potential predictors of adverse outcome in severe YFI.