37. Infectious diseases in pregnancy. Viral infections

Question 1

Pathogenesis of Rubella

Answer 1

mRNA virus; mild infection in adults.

Infected newborns shed the virus for many months; susceptible infants and adults are at risk.

Question 2

fetal presentation of Rubella

Answer 2

-“Blueberry muffin rash” (due to dermal extramedullary hematopoiesis).
-Cardiac defects including PDA and PS.
-Cataract, congenital glaucoma, blindness.
-Deafness; most common single defect.
-CNS defects: microcephaly and mental retardation.

Question 3

diagnosis of rubella in the fetus

Answer 3

presence in chorionic villi, amniotic fluid:
1. Rubella RNA
2. IgM antibody serology (Fetal blood can confirm fetal infection)

Question 4

treatment for rubella infection

Answer 4

supportive
only prevention–>MMRV vaccine (live-attenuated; should be given at least 1 month before conception).

Question 5

what is the most common cause of perinatal infection in the developed world?

Answer 5

cytomegalovirus (CMV)

Question 6

how is CMV fetal infection transmitted?

Answer 6

via intrauterine, intrapartum, or postpartum infection (breastfeeding).

Question 7

maternal presentation of CMV

Answer 7

• Mostly asymptomatic; mononucleosis-like illness (heterophile negative mononucleosis) in up to 15% of cases.
• Maternal immunity does not prevent reactivation, recurrence, exogenous infection, congenital infection, or infection from a different strain.
• Primary infection is associated with severe fetal morbidity.

Question 8

fetal presentation of CMV

Answer 8

• Intracranial calcifications.
• Chorioretinitis.
• Microcephaly, mental and motor retardation.
• Hemolytic anemia.
• Sensorineural deficits.

Question 9

diagnosis of fetal CMV

Answer 9

1. Measurement of maternal serum IgM and IgG is used to confirm infection of the mother.
   *If maternal primary infection is confirmed → invasive prenatal testing with US and amniocentesis.
2. US can show microcephaly, ventriculomegaly, intracranial calcifications.
3. PCR detects and quantifies viral DNA in amniotic fluid and fetal blood.

Question 10

what treatment is given to maternal and fetal CMV infection?

Answer 10

*Potential maternal treatment: ganciclovir, valganciclovir, foscarnet, cidofovir.
*No specific fetal treatment, or prophylaxis.

Question 11

how does a fetus contact HSV?

Answer 11

in the birth canal during delivery

Question 12

presentation of HSV fetal infection

Answer 12

cutaneous lesions, CNS involvement (microcephaly, meningoencephalitis, seizures), chorioretinitis, blindness.

Question 13

presentation of HSV maternal infection

Answer 13

genital herpes
multiple painful genital vesicles with an erythematous base that progress to painful ulcers; usually present 1-3 weeks after exposure.

Question 14

treatment of HSV

Answer 14

Valacyclovir, acyclovir, famciclovir.

Question 15

diagnosis of HSV

Answer 15

• Gross examination of the vulva for typical lesions (mother).
• newborn and mother: viral culture of HSV from skin lesions, conjunctiva, oro/nasopharynx, or rectum
• PCR of genital lesion or blood for HSV DNA.
• Western blot for viral serology.

Question 16

how does varicella zoster virus (VZV) present in adults and pregnancy?

Answer 16

More severe in adults; even more severe in pregnancy (maternal pneumonia).

Question 17

what are the fetal effects from VZV infection?

Answer 17

Early pregnancy → transplacental infection causes congenital malformations (chorioretinitis, cerebral atrophy, hydronephrosis, cutaneous and bone leg defects).
Late pregnancy → lower risk for congenital varicella infection.
Before/during labor → much higher risk to infants due to the absence of protective maternal antibodies; neonates may develop a disseminated disease that can be
fatal.

Question 18

diagnosis of VZV

Answer 18

presence of antibodies if immunity is uncertain

Question 19

treatment for VZV

Answer 19

1. Acyclovir, valacyclovir, or famciclovir for symptomatic adult disease
   2.Passive immunization with VZIG (anti-varicella immunoglobulins) within 96 h’ is
   indicated for those who are exposed and susceptible (maternal and/or newborn).

Question 20

is the Live-attenuated vaccine for VZV given to pregnant ane newborns

Answer 20

not recommended for pregnant women or newborns.
Not secreted in breast milk, so can give postpartum.

Question 21

how do neonates get HBV infection?

Answer 21

Most neonatal infections are due to ingestion of infected fluid in the peripartum period or with breastfeeding;
a small percentage of transplacental transmission.

Question 22

what antigen indicates there a high risk of infectivity?

Answer 22

↑ levels of HBeAg.

Question 23

presentation of HBV in neonates

Answer 23

Chronic infection occurs in 70-90% of acutely infected infants leading to cirrhosis and
hepatocellular carcinoma.

Question 24

when do we diagnose HBV infection of the pregnant women

Answer 24

Screen at the first prenatal visit and delivery with hepatitis B surface antigen (HBsAg).

Question 25

how do we prevent neonatal infection if mother positive for HBsAg?

Answer 25

1. Hepatitis B immunoglobulin (HBIG) given to infant upon delivery.
2. Give first of three hepatitis B vaccines upon delivery.

Question 26

The vast majority of cases of pediatric AIDS are?

Answer 26

secondary to vertical transmission from mother to fetus.
perinatal transmission is approx. 25%.

Question 27

how can we reduce the risk of vertical transmission of HIV during pregnancy?

Answer 27

1. If zidovudine (ZDV) is given during antepartum, intrapartum, and to neonate → risk of transmission is reduced to 8%.
   -Give IV to mother
   -ZDV syrup to newborn for 6 weeks
2. HAART started in the antenatal period can reduce the risk of transmission to 2%.
3. Reduce duration of ruptured membranes.
4. Recommend cesarean delivery before labor if viral load > 1000 copies.
5. Avoid breastfeeding.

Question 28

when is HIV screening recommended ?

Answer 28

at the first prenatal visit.
Screening test (ELISA) followed by a confirmatory test (Western blot or PCR).

Question 29

management of HIV pregnant women

Answer 29

1. Antiretroviral therapy should be encouraged in all HIV-infected pregnant women regardless of CD4+ count and viral load to reduce vertical transmission.
2. CD4+ counts and viral loads should be monitored at regular intervals.
3. Blood counts and LFTs should be monitored monthly while the patient is on ZDV.