Virus

Rubella

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Rubella, Third Viral Exanthem of Childhood, German Measles, Three Day Measles

  • Etiology
  1. Rubivirus (Togaviridae, pleomorphic RNA virus)
  • Epidemiology
  1. Incidence of Rubella cases
    1. U.S. Cases in 1964-5: 12 million cases
    2. U.S. Cases in 2000: 176 cases
  2. Incidence of congenital Rubella cases
    1. U.S. Cases in 1964-5: 20,000 cases
    2. U.S. Cases in 2000: 9 cases
    3. U.S. Cases in 2015: 6 cases
  • Pathophysiology
  • Transmission
  1. Person to person via oral droplets
  2. Vertical transmission (transplacental) results in congenital Rubella (90% risk in first trimester)
  3. Up to 60% transmission in susceptible family
  • Symptoms
  1. Subclinical in 50% of cases
  2. Known also as "Three Day Measles" for the shorter, more mild course
  3. Mild Upper Respiratory Infection symptoms
  4. Fever
  5. Pharyngitis
  6. Headache
  • Signs
  1. Mild Fever
  2. Significantly tender Lymphadenopathy
    1. Retroauricular, posterior auricular, Occipital Lymphadenopathy
  3. Rash
    1. Initially, exanthem may cover Soft Palate and face
    2. Later, rash begins on face and spreads to cover trunk
    3. Maculopapular rash with areas of confluence, Flushing
    4. Mild Pruritus
    5. Rash usually clears by Day 3 (hence the name: Three Day Measles)
  • Differential Diagnosis
  1. See Rash in the Febrile Patient
  2. Mononucleosis
    1. Also causes significant Lymphadenopathy
  3. Measles
    1. Conjunctivitis and Koplik Spots
  • Complications
  1. Encephalitis (1 case per 6,000 Rubella infections)
    1. Mortality from Encephalitis approaches 20%
  2. Arthritis (immune complex)
  3. Thrombocytopenia (1 case per 3000 Rubella infections)
  4. Immune-complex mediated Arthritis
  5. Congenital Rubella Syndrome
    1. Rubella is one of the TORCH Viruses
    2. Pregnant women should avoid Rubella exposure
      1. Avoid throughout pregnancy (especially early)
      2. Avoid exposure to infants with congenital Rubella
        1. Very high risk due to prolonged shedding
  • Management
  • High risk exposure occurs early in pregnancy
  1. Consider therapeutic abortion
  2. Give Rubella Immunoglobulin
  • Prevention
  1. Primary Series
    1. Immunization at Ages 12-15 months, and 4-6 years
  2. Preconception Counseling
    1. Test Rubella Immunity
    2. Vaccinate women not immune to Rubella
  • References
  1. Spencer (2017) Am Fam Physician 95(12): 786-94 [PubMed]