Dengue

(Redirected from Dengue Fever)

Background

World map highlighting areas of dengue risk.[1]
Femail Ades aegypti mosquito feeding on a person.
  • A viral infection transmitted though Aedes mosquitos typically in urban areas, especially during rainy seasons in tropical/subtropic regions (Asia, Africa, Central America, Caribbean)
  • Also known as "break-bone fever"
  • Most infections are asymptomatic or produce only mild illness, but the virus occasionally causes more severe cases up to death (i.e., "severe dengue")[2]
    • Severe dengue (which includes "dengue shock syndrome") is rare in travelers, as it is cause by a second infection of a different Dengue serotype (so patients must have had two separate exposures at different times to be at risk)

Clinical Features

Clinical course of dengue fever.
Early dengue rash.
Recover phase rash: classic islands of white in a sea of red.

Dengue

  • Incubation 3-7 days
  • Febrile phase:
    • High fever + "Break-bone" pain + GI symptoms + rash + possible exposure
    • +/- Faget sign
    • Lasts 3-7 days, majority recover

Severe Dengue

As above, followed by:

  • Critical Phase[3]:
    • 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

Differential Diagnosis

Fever in traveler

Evaluation

Work-up

  • Definitive testing
    • Reverse transcription polymerase chain reaction (RT-PCR) OR non-structural protein 1 (NS1) antigen tests, AND
    • IgM antibody tests
    • For public health purposes, these tests may be ordered regardless of time since symptom onset
  • May consider other tests to rule out other possible processes:
    • CBC, chemistry, LFTs, viral panels
    • If concern for Severe Dengue, add DIC labs

Diagnosis

When laboratory tests become positive. Day zero is symptom start. 1st = primary infection; 2nd = secondary infection.[4]
  • Typically a clinical diagnosis in the ED
  • Definitive testing
    • IgM diagnosed by a 4x increase in acute/ convalescent titers
  • Other possible lab findings:
  • Severe Dengue if any of the following identified:

Tourniquet Test

Example of positive tourniquet test (right arm).
  • Tests for capillary fragility as a sign of Severe Dengue
  • Typically used in the absence of available DIC labs (i.e., low-resource settings)
    • Sensitivity of 52% and specificity of 82.4%
    • A positive tourniquet test combined with lekuopenia increases sensitivity to 94%[5]
    • Inflate cuff to pressure between SBP & DBP, and leave for 5 min
    • (+) Test = 10-20 petechiae per square inch

Management

Dengue

Severe Dengue

Above plus:

Disposition

Dengue

  • Typically outpatient, if well hydrated and non-toxic appearing
  • May consider admitting certain high-risk patients (e.g., pregnant, extremes of age, concerning concomitant chronic disease)

Severe Dengue

  • Typically admitted
    • Consider ICU admission for patients with shock and end-organ damage

Prevention

  • Vaccine available for the prevention of dengue virus and associated severe sequelae, Dengvaxia.[6]
  • Only recommended for individuals 9-45 years old who have been infected once before with the virus[7].
  • If patient has confirmed or likely dengue virus infection and they live and/or work in an endemic area, have them follow up with PCP for vaccination.

See Also

References

  1. ↑ CDC. July, 2024. https://www.cdc.gov/dengue/areas-with-risk/?CDC_AAref_Val=https://www.cdc.gov/dengue/areaswithrisk
  2. ↑ WHO website. https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue#:~:text=There%20is%20no%20specific%20treatment%20for%20dengue.,often%20used%20to%20control%20pain.
  3. ↑ 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.
  4. ↑ Simmons CP, Farrar JJ, Nguyen vV, Wills B (April 2012). "Dengue" (PDF). The New England Journal of Medicine. 366 (15): 1423–32. doi:10.1056/NEJMra1110265. hdl:11343/191104. PMID 22494122. Archived from the original on 28 August 2021. Retrieved 24 September 2019.
  5. ↑ 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.
  6. ↑ Paz-Bailey G, Adams L, Wong JM, et al. Dengue Vaccine: Recommendations of the Advisory Committee on Immunization Practices, United States, 2021. MMWR Recomm Rep 2021;70(No. RR-6):1–16. DOI: http://dx.doi.org/10.15585/mmwr.rr7006a1
  7. ↑ Paz-Bailey G, Adams L, Wong JM, et al. Dengue Vaccine: Recommendations of the Advisory Committee on Immunization Practices, United States, 2021. MMWR Recomm Rep 2021;70(No. RR-6):1–16. DOI: http://dx.doi.org/10.15585/mmwr.rr7006a1
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