Updated: 6/8/2018

Dengue Fever

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Snapshot
  • A 35-year-old man presents to the local urgent care clinic in South America. He is completing a graduate school exchange program, studying tropical ecosystems and is bitten by mosquitoes almost every day. He reports a 3-day history of high fevers, chills, and myalgias. This morning, he noticed some blood in his urine and while blowing his nose. On physical exam, there is gingival bleeding. Laboratory evaluation reveals a mild transaminitis, thrombocytopenia, and hematuria.
Introduction
  • Classification
    • dengue virus
      • an enveloped positive single-stranded RNA virus
      • a flavivirus
    • transmission
      • Aedes mosquitoes
  • Epidemiology
    • incidence
      • tropical and subtropical areas of the world
    • risk factors
      • prior infection with dengue virus predisposes patients to severe dengue hemorrhagic fever
  • Pathogenesis
    • virus replicates in and destroys the bone marrow
    • plasma leakage is caused by increased capillary permeability
  • Associated conditions
    • dengue hemorrhagic fever or dengue shock syndrome
  • Prognosis
    • symptoms occur after 4-10 days
    • if untreated, mortality rates can be 20%
    • if treated, mortality rate is 2-5% in severe cases
Presentation
  • Symptoms
    • headache
    • myalgais and arthralgias
    • altered sense of taste
  • Physical exam
    • high fever
    • blanching confluent erythematous maculopapular rash
    • lymphadenopathy
    • may have pleural effusions
    • minor hemorrhage
      • petechiae
      • bleeding mucosa
      • epistaxis
    • in severe cases, plasma leakage occurs
      • bleeding from sites of trauma
      • gastrointestinal bleeding
      • severe abdominal pain
      • blood vomiting
    • positive tourniquet test
      • petechial observed below the cuff after a tourniquet (commonly an inflated blood pressure cuff) is left on for 5 minutes
Studies
  • Labs
    • antibodies to the dengue virus in the serum
    • detection of DNA in tissue, serum, or cerebral spinal fluid
    • lab abnormalities
      • thrombocytopenia
      • leukopenia
      • mild transaminitis
      • decreased fibrinogen
    • urinalysis
      • hematuria
    • guaiac stool testing
      • occult blood
  • Making the diagnosis
    • based on clinical presentation and laboratory studies
Differential
  • Yellow fever
    • distinguishing factor
      • may also be hemorrhagic but often affects the liver as well and manifests as jaundice, scleral icterus, and hepatomegaly
  • Zika virus infection
    • distinguishing factors
      • may also present with a viral prodrome and rash, but typically does not have any hemorrage
      • pregnant patients may give birth to infants with microcephaly and intracranial calcifications
  • Chikungunya
    • distinguishing factor
      • may also present with flu-like symptoms, joint pain, and rash but typically does not have any hemorrhage
Treatment
  • Management approach
    • the disease is typically self-limited and mainstay for treatment is supportive care
  • Conservative
    • supportive care
      • indication
        • all patients
      • modalities
        • rehydration
        • close monitoring
        • pain control
Complications
  • Shock
  • Death

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