Dengue Fever & Dengue Hemorrhagic Fever Definitions

From the 2001 Revised National Consensus on the Case Management of Dengue Fever & Dengue Hemorrhagic Fever

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Plasma leakage

Evidence of plasma leakage due to increased vascular permeability, manifested by at least one of the following:

  • Hemoconcentration: A rise in the hematocrit of > 20% above average of age, sex and population or greater than 20% drop in hematocrit following treatment with fluids as compared to baseline;
  • Clinical manifestations: edema, pleural effusion, ascites.

Hemorrhagic manifestations

Hemorrhagic manifestations include the following:

  • A positive tourniquet test
  • Petechiae, echymoses or purpuric rashes
  • Bleeding like epistaxis, gum bleeding, hematemesis or melena or from other sites

Case definition for dengue shock syndrome

All of the above four criteria for dengue hemorrhagic fever must be present, plus evidence of circulatory failure manifested by:

  • Rapid and weak pulse
  • Narrow pulse pressure (< 20 mm Hg)
  • Hypotension for age (<80 mm Hg systolic pressure for < 5 years of age and < 90 mm Hg systolic pressure for > 5 years of age
  • Cold, clammy skin and restlessness

Grading severity of dengue hemorrhagic fever

Dengue hemorrhagic fever is classified into four grades of severity, where grades II and IV are considered to be dengue shock syndrome.

Grade I
Fever accompanied by non-specific constitutional symptoms; the only hemorrhagic manifestation is a positive tourniquet test and/or easy bruising.
Grade II
Spontaneous bleeding in addition to the manifestations of Grade I patients, usually in the forms of skin or other hemorrhages.
Grade III
Circulatory failure manifested by a rapid, weak pulse and narrowing of pulse pressure or hypotension, with the presence of cold, clammy skin and restlessness.
Grade VI
Profound shock with undetectable blood pressure or pulse.

Laboratory criteria for confirmation of dengue fever

  • Serological confirmation
    • Demonstration of a fourfold or greater change in IgG antibody titers to one or more dengue virus antigens in paired serum samples.
    • Anti-dengue IgM ELISA positive (P/N > 2)
    • Samples for serological confirmation: 3-5 ml serum sample, refrigerated, sterile, obtained during early, acute and convalescent phase, with complete clinical information.
  • Virological confirmation
    • Isolation of the dengue virus from serum or autopsy samples
    • Demonstration of the dengue virus antigen by immunoflourescence (IFAT) or immunoperoxidase test
    • Demonstration of the dengue virus genome by RT-PCR using dengue consensus and serotype specific primers
    • Samples for virological confirmation: 1-2 ml serum sample preferably obtained 3-5 days after onset of fever.

Case definition for dengue hemorrhagic fever

The following must all be present:

  • Fever, or history of acute fever lasting 2-7 days
  • Thrombocytopenia (< 100,000 cells per cu. mm) or 1-2 platelets/oil immersion field

The consensus defined two categories of patients: those that can be treated at home and those who will require hospitalization.

Hospitalization will be required if danger signs are present; these danger signs anticipate bleeding or occurrence of shock.

Those requiring hospitalization are further subdivided into those with no evidence of shock and those with significant blood loss with or without shock.

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