RUBELLA


I. Epidemiology & nat. history

  1. Moderately contagious; caused by an RNA virus.
  2. Spread by nasopharyngeal secretions
  3. Infects resp. epithelium, proceeds to local lymph nodes & blood. Transplacental spread occurs.
  4. Infection is subclinical in 25-50% of cases
  5. Prodromal phase: 1-5d low-grade fever, HA, malaise, anorexia, pharyngitis & conjunctivitis
  6. Followed by rash: flat macules over face, neck, arms; spreads to entire body in 1d; gone in 3d
  7. Diagnosed primarily by rise in antibody titer

II. Congenital rubella Syndrome

  1. Chronic infection of fetus itself; requires active infection of mom during pregnancy (typically 1st trimester)
  2. Purpura, cataracts, "salt & pepper retinopathy," PA stenosis, PDA, AV septal defects, microcephaly, hepatosplenomegaly, sensorineural deafness, IUGR.
  3. Malformations seen 50% of infants infected 1st mo. of gestation; 20% in 2nd mo., 6% in 3rd mo., 1-2% in 4th-5th month

III. Management of rubella in pregnancy

  1. Rubella titer with intake OB labs
  2. If exposure occurs in seronegative woman, do 2nd titer 3-4wks after exposure; if pos., counsel regarding risks of cong. inf. & options re: termination
  3. Risk of vaccination in pregnancy
    1. In a prospective study of 94 women who received rubella vaccination in first 3mos of pregnancy and 94 matched controls not exposed to the vaccine, there were no cases of congenital rubella in the exposed group and no sig. diffs. among the groups in incidence of major fetal malformations, birth weights, or developmental milestones (Am. J. Med. Gen. 130A:52, 2004--abst)
  4. Can give antepartum Ig to seronegative moms w/exposure, but won't help baby; will, however, shorten mom's illness