Dengue

Background
  • Aedes mosquito in urban area, especially during rainy seasons in tropical/subtropic regions (Asia, Africa, Central America, Caribbean)
  • Dengue shock syndrome and hemorrhagic fever rare in travelers
    • Caused by second infection of different Dengue serotype

Clinical Features
  • Incubation 3-7 days
  • Febrile phase:
    • High fever + 'Breakbone' + GI symptoms + rash + possible exposure
    • +/- Faget sign
    • Lasts 3-7 days, majority recover
  • Critical Phase[1]:
    • Minority of patients, generally pediatric and elderly
    • Around time of defervescence
    • Vascular leak, hypoproteinemia, hemoconcentration, pleural effusion, ascites
    • Narrowed pulse pressure, persistent vomiting, RUQ tenderness, lethargy and restlessness are signs of impending collapse
    • Mucosal and skin bleeding
  • "Severe Dengue," any of the following:
    • Shock from plasma leakage
    • Hemorrhage
    • Respiratory distress

Differential Diagnosis

Fever in traveler

Evaluation

Work-up
  • Labs:
    • CBC: Leukopenia, thrombocytopenia, and hemoconcentration
    • CMP: LFTs elevated
    • DIC labs should be sent
    • Diagnose by 4x increase in acute/ convalescent titres - unlikely to be resulted in ED
  • Tourniquet Test - Tests capillary fragility
    • Sensitivity of 52% and specificity of 82.4%
    • A positive tourniquet test combined with lekuopenia increases sensitivity to 94%[2]
    • Inflate cuff to pressure between SBP & DBP, and leave for 5 min
    • (+) Test = 10-20 petechiae per square inch
Example of positive tourniquet test on the right

Evaluation
  • Clinical diagnosis

Management
  • Supportive Care
    • APAP for pain/fever
      • DO NOT use ASA due to hemorrhagic nature
  • IVFs
  • Blood Transfusion - consider in hemorrhagic shock

Disposition
  • Home - Well hydrated and non-toxic appearing
  • Admit - High-risk patients (ie pregnant, elderly, children, chronic disease)
    • ICU - patients with shock and end-organ damage

See Also

References
  1. Simmons, C.P., Farrar, J.J., van Vinh Chau, N. and Wills, B. (2012) ‘Dengue’, New England Journal of Medicine, 366(15), pp. 1423–1432.
  2. Gregory CJ, Lorenzi OD, Colón L, García AS, Santiago LM, Rivera RC, Bermúdez LJ, Báez FO, Aponte DV, Tomashek KM, Gutierrez J, Alvarado L. Utility of the tourniquet test and the white blood cell count to differentiate dengue among acute febrile illnesses in the emergency room. PLoS Negl Trop Dis. 2011 Dec;5(12):e1400.
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