infectious diseases
Dengue Hemorrhagic Fever Dengue Shock Syndrome
Diagnosis of Dengue Hemorrhagic Fever
Clinical and laboratory criteria Dengue hemorrhagic fever is suspected in children with World Health Organization–defined clinical criteria for the diagnosis: Sudden fever that stays high for 2 to 7 days Hemorrhagic manifestations Hepatomegaly Hemorrhagic manifestationsinclude at least a positive tourniquet test and petechiae, purpura, ecchymoses, bleeding gums, hematemesis, or melena. The tourniquet test is done by inflating a blood pressure cuff to midway between the systolic and diastolic blood pressure for 15 minutes. The number of petechiae that form within a 2.5-cm diameter circle are counted;>20 petechiae suggests capillary fragility. Complete blood count, coagulation tests, urinalysis, liver tests, and dengue serologic tests should be done. Coagulation abnormalities include Thrombocytopenia (≤ 100,000 platelets/mcL [≤ 100 x 109/L]) A prolonged prothrombin time (PT) Prolonged activated partial thromboplastin time (PTT) Decreased fibrinogen Increased amount of fibrin split products There may be hypoproteinemia, mild proteinuria, and increases in aspartate aminotransferase (AST) levels. Serological diagnosis can be made using the IgM capture enzyme-linked immunosorbent assay (MAC-ELISA). Combined with the dengue virus RNA amplification test, it can provide a diagnosis within the first 1 to 7 days of illness. The plaque reduction neutralization test (PRNT) is specific and sensitive. Titers in acute and convalescent phase serum samples can reliably establish dengue virus infection and may indicate the specific dengue virus type involved. The PRNT requires live dengue viruses for the test and is labor-intensive and expensive. Many laboratories are not able to do the PRNT. Patients with World Health Organization-defined clinical criteria plus thrombocytopenia (≤100,000/mcL [≤ 100 x 109/L]) or hemoconcentration (Hct increased by≥20%) are presumed to have the disease (see the Centers for Disease Control and Prevention'sDengue Virus: Clinical Guidance). 