Dengue: Difference between revisions
 
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==Background==
==Background==
[[File:Dengue-World-Map.png|thumb|World map highlighting areas of dengue risk.<ref>CDC. July, 2024. https://www.cdc.gov/dengue/areas-with-risk/?CDC_AAref_Val=https://www.cdc.gov/dengue/areaswithrisk</ref>]]
[[File:Dengue-World-Map.png|thumb|World map highlighting areas of dengue risk.<ref>CDC. July, 2024. https://www.cdc.gov/dengue/areas-with-risk/?CDC_AAref_Val=https://www.cdc.gov/dengue/areaswithrisk</ref>]]
[[File:Aedes aegypti CDC-Gathany.jpg|thumb|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)
*A viral infection transmitted though Aedes mosquitos typically in urban areas, especially during rainy seasons in tropical/subtropic regions (Asia, Africa, Central America, Caribbean)
**Los Angeles County reported 14 confirmed cases of locally acquired dengue in 2024<ref>http://publichealth.lacounty.gov/acd/VectorDengue.htm</ref>
*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")<ref>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.</ref>
*Most infections are asymptomatic or produce only mild illness, but the virus occasionally causes more severe cases up to death (i.e., "severe dengue")<ref>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.</ref>
**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 to be at risk)
**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 Features==
[[File:Course of Dengue illness vectorized.png|thumb|Clinical course of dengue fever.]]
[[File:Early Dengue Fever Rash 2014.jpg|thumb|Early dengue rash.]]
[[File:Dengue recovery rash (White islands in red sea).jpg|thumb|Recover phase rash: classic islands of white in a sea of red.]]
===Dengue===
*Incubation 3-7 days
*Incubation 3-7 days
*Febrile phase:
*Febrile phase:
**High [[fever]] + 'Breakbone' + GI symptoms + [[rash]] + possible exposure
**High [[fever]] + "Break-bone" pain + GI symptoms + [[rash]] + possible exposure
**+/- [[Faget sign]]
**+/- [[Faget sign]]
**Lasts 3-7 days, majority recover
**Lasts 3-7 days, majority recover
===Severe Dengue===
''As above, followed by:''
*Critical Phase<ref>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.</ref>:
*Critical Phase<ref>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.</ref>:
**Minority of patients, generally pediatric and elderly
**Minority of patients, generally pediatric and elderly
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**Narrowed pulse pressure, persistent [[vomiting]], RUQ tenderness, lethargy and restlessness are signs of impending collapse
**Narrowed pulse pressure, persistent [[vomiting]], RUQ tenderness, lethargy and restlessness are signs of impending collapse
**Mucosal and skin bleeding
**Mucosal and skin bleeding
*"Severe Dengue," any of the following:
**Shock from plasma leakage
**Hemorrhage
**Respiratory distress


==Differential Diagnosis==
==Differential Diagnosis==
{{Template:Fever in Traveler DDX}}
{{Fever in Traveler DDX}}


==Evaluation==
==Evaluation==
===Work-up===
===Work-up===
[[File:Tourniquettest.gif|thumbnail|Example of positive tourniquet test on the right]]
*Consider tests to rule out other possible processes:
*Labs:  
**CBC, chemistry, LFTs, viral panels
**[[West Nile virus]] testing (see testing cross-reactivity concerns below)
**See [[Fever in traveler]]
*Definitive dengue testing (all are serum tests)
**Acute phase (0-7 days post symptom onset)<ref>https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html</ref>
***Nucleic acid amplification test (NAAT) (e.g., RT-PCR) '''OR''' NS1 ELISA test, '''AND'''
***IgM antibody test
**Convalescent Phase (>7 days post symptom onset)<ref>https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html</ref>
***''For public health purposes, many agencies request the same testing as for 0-7 days above''<ref>LAC DPH Health Alert Locally Acquired Case of Dengue in Los Angeles County September 9, 2024; chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/http://publichealth.lacounty.gov/eprd/lahan/alerts/LAHANAlertDengue090924.pdf</ref>
***IgM antibody (alone)
*Concern for Severe Dengue
**Add [[DIC]] labs
 
===Diagnosis===
[[File:Dengue testing.png|thumb|When laboratory tests become positive. Day zero is symptom start. 1st = primary infection; 2nd = secondary infection.<ref>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.</ref>]]
''In the US, dengue is a nationally notifiable disease and all suspected cases should be reported to the local health department.''
*Typically a clinical diagnosis in the ED
**All patients with clinically suspected dengue should receive appropriate management without waiting for diagnostic test results.
*Definitive testing
**Positive
***A positive NAAT test does not require further confirmatory testing.
***A positive NS1 test during the first 7 days of illness is indicative of a current or recent dengue virus infection.
***A positive IgM antibody test
****Diagnosed by a 4x increase in acute vs convalescent titers
****Is limited by possible cross reactivity against other flaviviruses (e.g., [[Zika]], [[Japanese encephalitis]], St. Louis encephalitis, [[West Nile]], [[yellow fever]]) viruses
**Negative
***A negative result from a RT-PCR or NS1 ELISA test does ''not'' rule out infection.
**IgG detection should not be used to diagnose acute dengue because it does not distinguish between current and previous infection.
*Other possible lab findings:  
**CBC: [[Leukopenia]], [[thrombocytopenia]], and hemoconcentration
**CBC: [[Leukopenia]], [[thrombocytopenia]], and hemoconcentration
**CMP: LFTs elevated
**CMP: LFTs elevated
**[[DIC]] labs should be sent
**[[DIC]] lab abnormalities
**Diagnose by 4x increase in acute/ convalescent titres - unlikely to be resulted in ED
*Severe Dengue if any of the following identified:
*Tourniquet Test - Tests capillary fragility
**[[Shock]] (from plasma leakage)
**Hemorrhage
**[[Respiratory distress]]
 
===Tourniquet Test===
[[File:Tourniquettest.gif|thumbnail|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%
**Sensitivity of 52% and specificity of 82.4%
**A positive tourniquet test combined with lekuopenia increases sensitivity to 94%<ref>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. </ref>
**A positive tourniquet test combined with lekuopenia increases sensitivity to 94%<ref>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. </ref>
**Inflate cuff to pressure between SBP & DBP, and leave for 5 min
**Inflate cuff to pressure between SBP & DBP, and leave for 5 min
**(+) Test = 10-20 petechiae per square inch
**(+) Test = 10-20 petechiae per square inch
*Definitive testing
**Reverse transcription polymerase chain reaction [RT-PCR] and IgM antibody tests, 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
===Diagnosis===
*Clinical diagnosis


==Management==
==Management==
''No specific antiviral treatment for dengue is available.''
===Dengue===
*Supportive Care
*Supportive Care
**[[Acetaminophen]] for pain/fever
**[[Acetaminophen]] for pain/fever
***DO NOT use [[aspirin]] due to hemorrhagic nature
***DO NOT use [[aspirin]] or [[ibuprofen]] due to increased risk of hemorrhage
*[[IVFs]]
**PO hydration
*Blood [[Transfusion]] - consider in hemorrhagic shock
 
===Severe Dengue===
Above plus:
*Treatment is supportive and requires careful volume management
**Monitor for shock and reduce the risk of complications resulting from increased vascular permeability, plasma leakage, and organ damage.
*[[IVFs]] (mainstay of supportive care)
*Consider blood [[transfusion]] if hemorrhagic shock
*Prophylactic platelet transfusions and steroids are ''not'' recommended


==Disposition==
==Disposition==
*Home - Well hydrated and non-toxic appearing
===Dengue===
*Admit - High-risk patients (ie pregnant, elderly, children, chronic disease)
*Typically outpatient, if well hydrated and non-toxic appearing
**ICU - patients with shock and end-organ damage
**May consider admitting certain high-risk patients (e.g., pregnant, extremes of age, concerning concomitant chronic disease)
*Advise to:
**Say well hydrated
**Avoid [[aspirin]] and other [[NSAIDs]]. Fever should be controlled with acetaminophen and tepid sponge baths. 
*For at least one week, avoid mosquitoes and use insect repellent to prevent additional spread.
 
===Severe Dengue===
*Typically admitted
**Consider ICU admission for patients with shock and end-organ damage


==Prevention==
==Prevention==
*Vaccine available for the prevention of dengue virus and associated severe sequelae, Dengvaxia.<ref>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</ref>
*The vaccine Dengvaxia was approved by the Food and Drug Administration in 2021 and was recommended for children and adolescents aged 9 – 16 years who had a laboratory confirmed previous dengue virus infection AND live in areas where dengue is common. However, production was discontinued due to low demand and currently, no vaccines are available.<ref>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</ref><ref>http://publichealth.lacounty.gov/acd/VectorDengue.htm</ref><ref>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</ref>.
*Only recommended for individuals 9-45 years old who have been infected once before with the virus<ref>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</ref>.
*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==
==See Also==

Latest revision as of 20:02, 16 April 2025

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)
    • Los Angeles County reported 14 confirmed cases of locally acquired dengue in 2024[2]
  • 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")[3]
    • 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[4]:
    • 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

  • Consider tests to rule out other possible processes:
  • Definitive dengue testing (all are serum tests)
    • Acute phase (0-7 days post symptom onset)[5]
      • Nucleic acid amplification test (NAAT) (e.g., RT-PCR) OR NS1 ELISA test, AND
      • IgM antibody test
    • Convalescent Phase (>7 days post symptom onset)[6]
      • For public health purposes, many agencies request the same testing as for 0-7 days above[7]
      • IgM antibody (alone)
  • Concern for Severe Dengue

Diagnosis

When laboratory tests become positive. Day zero is symptom start. 1st = primary infection; 2nd = secondary infection.[8]

In the US, dengue is a nationally notifiable disease and all suspected cases should be reported to the local health department.

  • Typically a clinical diagnosis in the ED
    • All patients with clinically suspected dengue should receive appropriate management without waiting for diagnostic test results.
  • Definitive testing
    • Positive
      • A positive NAAT test does not require further confirmatory testing.
      • A positive NS1 test during the first 7 days of illness is indicative of a current or recent dengue virus infection.
      • A positive IgM antibody test
    • Negative
      • A negative result from a RT-PCR or NS1 ELISA test does not rule out infection.
    • IgG detection should not be used to diagnose acute dengue because it does not distinguish between current and previous infection.
  • 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%[9]
    • Inflate cuff to pressure between SBP & DBP, and leave for 5 min
    • (+) Test = 10-20 petechiae per square inch

Management

No specific antiviral treatment for dengue is available.

Dengue

Severe Dengue

Above plus:

  • Treatment is supportive and requires careful volume management
    • Monitor for shock and reduce the risk of complications resulting from increased vascular permeability, plasma leakage, and organ damage.
  • IVFs (mainstay of supportive care)
  • Consider blood transfusion if hemorrhagic shock
  • Prophylactic platelet transfusions and steroids are not recommended

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)
  • Advise to:
    • Say well hydrated
    • Avoid aspirin and other NSAIDs. Fever should be controlled with acetaminophen and tepid sponge baths.
  • For at least one week, avoid mosquitoes and use insect repellent to prevent additional spread.

Severe Dengue

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

Prevention

  • The vaccine Dengvaxia was approved by the Food and Drug Administration in 2021 and was recommended for children and adolescents aged 9 – 16 years who had a laboratory confirmed previous dengue virus infection AND live in areas where dengue is common. However, production was discontinued due to low demand and currently, no vaccines are available.[10][11][12].

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. ↑ http://publichealth.lacounty.gov/acd/VectorDengue.htm
  3. ↑ 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.
  4. ↑ 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.
  5. ↑ https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
  6. ↑ https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
  7. ↑ LAC DPH Health Alert Locally Acquired Case of Dengue in Los Angeles County September 9, 2024; chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/http://publichealth.lacounty.gov/eprd/lahan/alerts/LAHANAlertDengue090924.pdf
  8. ↑ 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.
  9. ↑ 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.
  10. ↑ 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
  11. ↑ http://publichealth.lacounty.gov/acd/VectorDengue.htm
  12. ↑ 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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