Criteria for clinical diagnosis of DHF /
DSS

1. Acute onset fever. Continuous and high grade after 2-7 days.
2. Hemorrhagic manifestations - (including at least positive tourniquet test), petechiae, purpura, ecchymosis, epistaxis gum bleeds, hematuria, malena etc.
3. Hepatomegaly
4. Shock - Rapid, weak pulse with narrow pulse pressure (< 20%), hypotension, cold clumsy skin and restlessness.

Laboratory criteria:

1. Thrombocytopenia (< 1 lakh/mm3).
2. Hematocrit increased by > 20%.

Fever, hemorrhagic manifestations, thrombocytopenia with rising hematocrit are sufficient for clinical diagnosis of dengue hemorrhagic fever (DHF). pleural effusion and hypoalbuminemia are supportive evidences.

Grading of Severity of DHF:

1. Fever, non-specific constitutional symptoms. The only positive hemorrhagic manifestation is a positive tourniquet test.
2. Above manifestations + spontaneous bleeding in skin and/or other hemorrhages.
3. Circulatory failure - rapid and weak pulse, narrow pulse pressure (< 20 m Hg) etc.

Differential diagnosis - Viral, bacterial, protozoal infection. Leptospirosis, malaria, infectious hepatitis, meningococcemia, rubella, influenza.

Complications:


Definitive diagnosis :
Confirmatory lab studies for dengue virus infection include:

1. Isolation of virus - Most definitive but not feasible and requires time, skills, expertise and equipments.
2. Demonstration of rising titre of specific dengue antibodies.
3. Demonstration of specific viral antigen/RNA in the tissue or serum.

Serological tests:


Management:
Early diagnosis and treatment reduces mortality and morbidity.