Dengue Fever

General Information

Cause: Dengue Flavivirus (arbovirus), serotypes 1-4

Transmission

Aedes aegypti, Aedes albopictus mosquitoes

  • Well adapted to human dwellings
  • Estimated that one in twenty homes may contain infected mosquito in endemic areas
  • Outbreaks tend to occur early in rainy season

Vertical Transmission

  • Mothers infected up to five weeks before delivery can result in acute neonatal dengue
  • Fever, cyanosis, apnea, mottling, hepatomegaly, thrombocytopenia

Distribution

  • Tropical/subtropical regions, specifically Asia, Africa, Central America, Caribbean
  • Most cases occur in Southeast Asia (Indonesia, Myanmar, Sri Lanka, Cambodia, Thailand in particular)
  • Mosquitoes cannot live at high altitude, such as the Andes
  • There have been increased reports of dengue in US Virgin Islands, Puerto Rico, and US-Mexico border areas

Incidence

  • 50-100 million cases of fever worldwide
  • Hundreds of thousands of cases of hemorrhagic fever yearly
  • Concern for increasing number of cases with global increase in temperature, increased population density, and increased world air travel
  • Children are at higher risk of severe infection. Children ages 7-12 are most common age group for hemorrhagic fever and shock.

Definitions to Consider

Dengue: Name of arbovirus
Dengue Fever: Also called “breakbone fever.” Variable presentation depending on age, ranging from mild to severe febrile illness.
Dengue Hemorrhagic Fever: Fever + hemorrhagic manifestations + thrombocytopenia + plasma leakage
Dengue Hemorrhagic Shock: Hemorrhagic fever + hypovolemia/shock + coagulopathy/DIC + severe bleeding

Clinical Manifestations

High Fever

  • Often >39°C, lasts 2-7 days
  • Often has brief resolution and recurrence

“Breakbone”

  • Headache, often frontal or retro-orbital
  • Arthralgias and myalgias after onset of fever can be severe and debilitating

GI Symptoms

  • Abdominal pain
  • Nausea, vomiting, anorexia
  • Hepatomegaly
  • GI bleeding in hemorrhagic forms

Rash

  • Starts as flushed skin
  • As fever subsides, macular rash that spares palms and soles may develop
  • Rash fades and desquamates, often leaving groups of petechiae on extensor surfaces

Tourniquet Test

Test for capillary fragility

  1. Apply BP cuff to arm at pressure midway between systolic and diastolic BP.
  2. Leave in place for 5 minutes at above pressure.

Positive if there are greater than 10-20 petechiae per square inch.

Diagnosis

Primarily clinical.

Criteria for Probable Dengue

  • Live in or travel to endemic area with fever and two of the following:

    *Abdominal pain, fluid overload, mucosal bleed, lethargy, hepatomegaly, increased HCT
  • Severe dengue
    • Plasma leakage: shock, respiratory distress
    • Hemorrhage
    • Organ involvement: altered mental status, elevated LFTs

Laboratory Investigation

  • Confirmatory studies unlikely to help EM physician
    • Viral culture
    • PCR
    • IgM, IgG seroconversion
  • CBC: hemoconcentration from plasma loss, leukopenia is characteristic of disease
  • CMP: evaluate LFTs. Hepatitis can be fatal
  • Coags, including d-dimer: DIC is complication of severe disease

Imaging

  • CXR, US to evaluate for pleural effusion from capillary leakage
  • Some studies suggest that gallbladder may be thickened in severe pediatric cases

Differential Diagnosis

*Emerging infectious disease with similar presentation, associated with fever and prolonged arthralgias for up to years.

Management

Dispo is Key Decision in Management

  • Patients who are well-hydrated and without warning signs can be sent home
    • Patients should be instructed to return to ED if they develop abdominal pain, signs of bleeding (epistaxis, GI, vaginal), dehydration, SOB, or altered mental status.
  • High-risk patients (pregnant, elderly, children, chronic disease) should be admitted
  • ICU for patients in shock, evidence of end-organ damage, or requiring transfusion.

Treatment

  • No specific medication for dengue, however, good supportive care has substantially decreased mortality
  • Acetaminophen
  • Do not use aspirin, due to hemorrhagic nature of the disease
  • Crystalloid IVF are mainstay of treatment. Slightly above maintenance IVF is ideal once patient has been resuscitated, generally speaking. WHO guidelines offer more comprehensive algorithm.

Treatment Updates

  • Adding blood component transfusion to children in hemorrhagic shock may be beneficial, though the stage of illness at administration is still unclear.
  • Review of 284 patients with dengue shock treated with corticosteroids showed no improvement in mortality or need for transfusion.
  • Small studies and case reports indicate that anti-D immunoglobulin may increase platelet count in thrombocytopenic patients.
  • Chloroquine shows no improvement in hospitalized patients.
  • Starch preferred to dextran in severe shock in children, though isotonic crystalloids are still preferred to both.

Prevention

  • Several vaccines are available, but no vaccine has shown efficacy at this point.
  • Geared towards individual/household protection from mosquitoes and environmental elimination.

Advice for Those Traveling to Endemic Regions

  • Wear clothing that covers arms and legs, particularly in morning and late afternoon.
  • Use insect repellant.
  • Choose accommodations with well-screened windows or air conditioning.
  • Mosquitoes tend to live indoors and live in cool places (closets, under beds, behind curtains, in bathrooms, in vases).

Further Reading

Tomashek KM, Margolis HS. CDC Traveler’s Health. Chapter 3: Infectious diseases related to travel. Dengue. Accessed 29 Dec 2013.

Halstead SB. Dengue. Lancet: 2007 Nov 10; 370(9599): 1644-52

World Health Organization. 2009 Dengue: Guidelines for diagnosis, treatment, prevention, and control. Geneva: WHO.

Alejandria M. Dengue haemorrhagic fever or dengue shock syndrome in children. Clinical Evidence 2009; 01: 917.

Panpanich R, Sornchai P, Kanjanaratanokorn K. Corticosteroids for treating dengue shock syndrome. Cochrane Database of Systematic Reviews 2009 (4).

Fever in the returning traveler.

Febrile illness in a young traveler: dengue fever and its complications.

Edited by Alex Koyfman, MD

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