Pathophysiology and management of dengue hemorrhagic fever

Abstract

SUMMARYDengue infection is caused by any of four dengue virus serotypes. The clinical manifestations range from asymptomatic infection to undifferentiated fever, dengue fever and dengue hemorrhagic fever (DHF). DHF is characterized by sustained high fever for 2–7 days; bleeding diathesis such as positive tourniquet test, petechiae, epistaxis and hematemesis; thrombocytopenia with platelet counts ≤ 100 × 109/L and plasma leakage due to increased vascular permeability evidenced by hemoconcentration, pleural effusion and ascites. Bleeding diathesis is caused by vasculopathy, thrombocytopenia, platelet dysfunction and coagulopathy. The three stages of clinical presentations are classified as febrile, toxic and convalescent. The toxic stage, which lasts 24–48 hours, is the most critical period, with rapid plasma leakage leading to circulatory disturbance. The severity of DHF varies from mild (World Health Organization grades I and II), with minimal and transient change in vital signs, to severe (World Health Organization grades III and IV), with threatened shock (e.g. blood pressure 100/90 mmHg) or profound shock. There is no specific treatment for DHF. Intensive supportive care is the most important aspect of management. Early recognition of the disease and careful monitoring for circulatory disturbance are essential. Optimal fluid therapy to maintain the functions of the vital organs during the critical period and effective control of bleeding episodes will lead to favorable outcomes. Administration of recombinant activated factor VII is suggested whenever massive bleeding does not respond to blood component therapy.