Parvovirus B19

  • “Parvo” porque é pequeno - único vírus de DNA de cadeia simples
  • Fisiopatologia
    • Tropismo para células eritroides progenitoras imaturas, resultando em lise celular
    • Leva a anemia, particularmente em doentes com anemia falciforme (pode dar crise aplástica)
  • Apresentação clínica
    • Most asymptomatic
    • Extracutaneous
      • Acute erythroblastic crisis in chronic hemolytic anemia
      • Glomerulonephritis
      • Inflammatory rhematism
      • Encephalitis
    • Cutaneous
      • In children: Epidemic megalerythema, Fifth disease
        • “Slapped cheek” rash in children
        • Stage 1: maculopapular erythema of the face
        • Stage 2: pale, pink macules with circinate contours forming garlands of the “prettiest erythem” predominantly on the limbs
        • Stage 3: fading with resurgence of the erythema exacerbated by physical exercise, changes in temperature, bathing, sun exposure
      • In adults: Arthropathy syndrome +/- rash
        • Artropatia devido a deposição de complexos imunes
        • Urticaria
        • Pulmonary intertitial syndrome → dry cough
        • Palmoplantar desquamation
      • No feto: Hydrops fetalis
        • 1st trimester → abortion
        • 2nd and 3rd trimester → erythroblastopenia → hidrops fetalis
        • Test pregnant women for IgM antibodies if they have been in contact with parvovirus B19
        • If seroconversion → serial doppler U/S of fetus
        • Diagnosis can be confirmed with PCR on fetal blood
        • Antenatal transfusion may be necessary
      • Papular purpuric gloves and socks syndrome
      • Pityriasis lichenoides
      • Red baby syndrome
      • Kikuchi-Fujimoto lymphadenitis
      • Vasculitis
      • Connective tissues
        • May mimick lupus
        • “Authentic” SLE has been reported triggered by parvovirus