Updated: 6/29/2018

Zika Virus

Review Topic
  • A 30-year-old G1P0 woman delivers a baby with microcephaly at 38 weeks via normal spontaneous vaginal delivery. During her first trimester, she went on a trip to Puerto Rico in December of 2015 and had multiple mosquito bites there. A week after this trip, she had a low-grade fever, itchy maculopapular rash, and conjunctivitis that resolved within 10 days. She had not gone consistently to her prenatal appointments. On physical exam, the baby has congenital microcephaly. A serum sample from the baby is collected.
  • Classification
    • Zika virus
      • an enveloped positive-sense, single-stranded RNA flavivirus
    • transmission
      • Aedes mosquitoes
      • can be vertically and sexually transmitted
  • Epidemiology
    • incidence
      • more common in tropical and subtropical climates
      • Central and South America
      • the Caribbean
    • risk factors
      • mosquito exposure
      • travel to endemic areas
      • sexual exposure to others who have traveled to endemic areas
  • Pathogenesis
    • the Zika virus replicates in skin cells (e.g., keratinocytes and fibroblasts), which undergo cell death
    • the virus spreads via blood and induces an innate immune response
      • may potentially penetrate through the placental barrier, leading to teratogenicity
  • Associated conditions
    • microcephaly
    • Guillain-Barré syndrome
  • Prognosis
    • most infections are asymptomatic
    • if symptomatic, the disease will occur 3-12 days after exposure
      • typically, the disease is self-limited
    • if vertically transmitted and depending on time of infection, fetuses may have microcephaly, intracranial calcifications, and cerebral malformation
  • Symptoms
    • Zika virus infection
      • may have a pruritic rash
      • miscarriage
      • arthralgia
      • headache
      • hematospermia (in males)
  • Physical exam
    • Zika virus infection
      • conjunctival injection
      • low-grade fever
      • macular or papular rash
    • vertically transmitted to fetus
      • congenital microcephaly
      • intracranial calcifications
      • ocular lesions
  • Labs
    • serum or urine Zika virus immunoglobulin M (IgM)
      • often the initial test
      • screen in pregnant women with risk factors during the first and second trimester
    • serum or urine reverse-transcriptase polymerase chain reaction (RT-PCR)
      • confirmatory testing if IgM is positive
  • Making the diagnosis
    • based on clinical presentation and laboratory studies
  • Dengue fever
    • distinguishing factor
      • often presents with signs of hemorrhage and without conjunctivitis
  • Conservative
    • supportive care
      • indication
        • all patients
      • modalities
        • hydration
        • pain control
        • anti-pyretic medications
  • Permanent neurologic damage
  • Guillain-Barré syndrome

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