Cause: Dengue Flavivirus (arbovirus), serotypes 1-4
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
- Mothers infected up to five weeks before delivery can result in acute neonatal dengue
- Fever, cyanosis, apnea, mottling, hepatomegaly, thrombocytopenia
- 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
- 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
- Often >39°C, lasts 2-7 days
- Often has brief resolution and recurrence
- Headache, often frontal or retro-orbital
- Arthralgias and myalgias after onset of fever can be severe and debilitating
- Abdominal pain
- Nausea, vomiting, anorexia
- GI bleeding in hemorrhagic forms
- 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
Test for capillary fragility
- Apply BP cuff to arm at pressure midway between systolic and diastolic BP.
- Leave in place for 5 minutes at above pressure.
Positive if there are greater than 10-20 petechiae per square inch.
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
- Organ involvement: altered mental status, elevated LFTs
- Confirmatory studies unlikely to help EM physician
- Viral culture
- 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
- CXR, US to evaluate for pleural effusion from capillary leakage
- Some studies suggest that gallbladder may be thickened in severe pediatric cases
*Emerging infectious disease with similar presentation, associated with fever and prolonged arthralgias for up to years.
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.
- No specific medication for dengue, however, good supportive care has substantially decreased mortality
- 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.
- 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.
- 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).
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).