What are the danger signs of dengue?

Danger Signs of Dengue

The danger signs of dengue that require immediate medical attention include persistent vomiting, abdominal pain/tenderness, clinical fluid accumulation, mucosal bleeding, lethargy/restlessness, hepatomegaly >2cm, and hematocrit rise with concurrent thrombocytopenia. 1, 2

Clinical Spectrum of Dengue

Dengue infection presents as a spectrum ranging from:

• Mild febrile illness (classic dengue fever) 3
• Dengue hemorrhagic fever (DHF) 3
• Dengue shock syndrome (DSS) - rare in travelers 3

Warning Signs Indicating Severe Disease Progression

Gastrointestinal Warning Signs

• Persistent vomiting - highly specific for progression to severe dengue 4, 5
• Abdominal pain or tenderness - associated with higher risk of severe dengue 4
• Hepatomegaly >2cm - highly specific indicator for severe disease progression 4, 5

Fluid-Related Warning Signs

• Clinical fluid accumulation (pleural effusion, ascites) - one of the strongest predictors of severe dengue with odds ratio of 3.7 4, 6
• Pleural effusion - detected clinically or radiologically 4
• Ascites - indicates capillary leakage and potential progression to shock 4

Hematological Warning Signs

• Mucosal bleeding (epistaxis, gum bleeding, gastrointestinal bleeding) - associated with higher risk of severe dengue 4, 7
• Hematocrit rise with concurrent thrombocytopenia (platelets <100 × 10⁹/L) - significant predictor with odds ratio of 2.2 4, 6
• Skin bleeding - may indicate coagulopathy 4

Neurological Warning Signs

• Lethargy or restlessness - indicates potential central nervous system involvement 4
• Impaired consciousness - serious sign requiring immediate medical attention 4

Timing of Warning Signs

• Warning signs typically appear around day 3-7 of illness, coinciding with defervescence 2
• Warning signs occur approximately two days before progression to severe dengue 5

Diagnostic Considerations

• PCR testing is most effective in the first few days of infection during viremia 1
• NS1 antigen detection is useful in the acute phase (detectable from day 1 to day 10 after symptom onset) 1
• IgM antibody testing becomes appropriate after the first week of illness 1

High-Risk Groups

• Patients with comorbidities have higher risk of progression to severe dengue 4
• Secondary dengue infections carry higher risk of severe manifestations 4

Clinical Pitfalls

• No single warning sign alone has sensitivity >64% for predicting severe disease 5
• Combination of any 3-4 warning signs has high specificity (>90%) but lower sensitivity 5
• Respiratory symptoms like dyspnea may be overlooked but are associated with severe disease 4
• Gastrointestinal bleeding may be mistaken for primary gastrointestinal pathology rather than dengue complication 7

Management Implications

• Presence of any warning sign warrants close monitoring and consideration for hospitalization 1, 2
• Early recognition of warning signs and appropriate management can reduce case-fatality rate to <0.5% 2