dengue hemorrhagic fever

Dengue Hemorrhagic fever/ Dengue Shock Syndrome/ severe dengue Definition – associated with dengue virus infection, particularly those occurring against background of previous exposure to another dengue virus serotype.The transient heterotypic protection after dengue virus infection is replace within several weeks by potential heterotypic infection due to typical dengue fever or uncommonly enhance disease (secondary DHF/DSS) Epidemiology – rarely primary infection lead to HF syndrome. Southeast Asian serotype 2 strain more potential to cause DHF/DSS. Most patient response well to supportive therapy, and overall mortality rate at an experienced center in the tropics probably at low as 1%. Widespread in southeast asian and west pacific region. Occuring in most tropical country in asia. DHF occur exclusively in children under 16 years old and is associated with secondary dengue infection. DHF is usually associated with secondary dengue infection but can appear during a primary infection, especially in infants under the age of 1 year, all of whom possess maternal IgG dengue antibody Diagnosis DHF – bleeding tendencies ( tourniquet test. Petechiae) or overt bleeding in the absence of underlying causes such as preexisting GI lesion. DSS – hemorrhagic signs, is much more serious and result in increase vascular permeability leading to shock. Mild DHF/DSS – restlessness, lethargy, thrombocytopenia (<100,000/µL) and hemoconcentration are detected 2-5 days after onset of typical dengue fever, usually at the time of defervescence. More severe case, frank shock is apparent, with low pulse pressure, cyanosis, hepatomegaly, pleural effusions, ascites and some cases severe ecchymosed and GI bleeding Virological diagnosis Aetiological diagnosis can be confirmed by serological testing and virus detection by isolation or molecular technique from the blood during the early febrile phase. Antibodies to dengue virus antigens increase rapidly in patients with secondary dengue infection. A diagnostic (four-fold) increase in dengue antibody by the haemagglutination inhibition test can usually be demonstrated from paired sera obtained early in the febrile phase or on admission, and 3–5 days later. A third specimen 2–3 weeks after onset is, however, required to confi rm diagnosis of primary dengue infection. Serological diagnosis by detection of anti-dengue IgM and IgG by enzyme-linked immunosorbent assay (ELISA) is now widely used to document primary and secondary infection. IgM antibody capture (MAC) – ELISA is a relatively new test. It is specific in distinguishing dengue from other flavivirus infections and has the advantage over the haemagglutination test in that a definite diagnosis can be made from an acute blood specimen alone.

dengue hemorrhagic fever

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