From the Guidelines
To diagnose dengue hemorrhagic fever, you should first look for the classic triad of high fever, hemorrhagic manifestations, and thrombocytopenia (low platelet count) and utilize a combination of clinical assessment, laboratory tests such as complete blood count, dengue-specific tests like NS1 antigen detection, and serological tests for IgM and IgG antibodies, as well as PCR testing to detect viral RNA in early stages, as recommended by the most recent guidelines 1.
Clinical Assessment
Begin with a thorough clinical assessment, noting symptoms like:
- Severe headache
- Retro-orbital pain
- Muscle and joint pain
- Nausea
- Vomiting
- Rash Physical examination should focus on identifying warning signs such as:
- Bleeding (petechiae, ecchymosis, gum bleeding, epistaxis)
- Plasma leakage (pleural effusion, ascites)
- Signs of shock
Laboratory Confirmation
Laboratory confirmation is essential and includes:
- Complete blood count (look for progressive decrease in platelet count below 100,000/mm³ and hemoconcentration with hematocrit increase of 20% or more)
- Dengue-specific tests like NS1 antigen detection (positive in first 5 days)
- Serological tests for IgM and IgG antibodies (IgM detectable 5-7 days after onset)
- PCR testing can detect viral RNA in early stages
Monitoring and Treatment
Monitor patients closely for signs of progression to severe disease, including:
- Abdominal pain
- Persistent vomiting
- Fluid accumulation
- Mucosal bleeding
- Lethargy
- Liver enlargement Early diagnosis is crucial as dengue hemorrhagic fever can rapidly progress to dengue shock syndrome, which has high mortality if not promptly treated with appropriate fluid management and supportive care, as emphasized in the guidelines 1. Some key points to consider when interpreting test results include:
- A positive NAAT result typically provides evidence of acute infection
- A negative NAAT result does not exclude dengue or Zika virus infection
- IgM antibody testing should be performed on NAAT-negative serum specimens and serum collected >7 days after onset of symptoms
- PRNTs can be used to confirm the diagnosis and differentiate between dengue and Zika virus infections, as recommended in the guidelines 1.
From the Research
Diagnosis of Dengue Haemorrhagic Fever
To diagnose dengue haemorrhagic fever, the following steps can be taken:
- Clinical manifestations such as fever, hemorrhagic manifestations, thrombocytopenia, and hemoconcentration should be identified 2
- Laboratory findings including rising hematocrit, thrombocytopenia, and transformed lymphocytes on peripheral smear can be used to support the diagnosis 2
- Viral culture can be done on blood obtained from patients during the early phase of illness to confirm dengue virus infection 2
- Antibodies against dengue virus can be demonstrated by various techniques in the later part of the illness 2
- Point-of-care combination tests capable of detecting markers of infection present during different stages of infection (viral nonstructural protein 1 and immunoglobulin M) can be used for laboratory-based dengue diagnosis 3
Diagnostic Criteria
The World Health Organization (WHO) definition for dengue hemorrhagic fever includes:
- Plasma leakage
- Thrombocytopenia
- Hemorrhagic tendency 4 However, hemorrhagic tendency does not reliably differentiate dengue fever and dengue hemorrhagic fever 4
Laboratory Diagnosis
Laboratory diagnosis of dengue virus infection can be done using:
- Virus detection
- Serological conversion 3
- Point-of-care combination tests 3
- Viral culture 2
- Antibody detection 2, 5
Challenges in Diagnosis
There are significant challenges in the clinical management of dengue-infected patients, especially in the absence of reliable biomarkers that provide an effective prognostic indicator of severe disease progression 3