37. Infectious diseases in pregnancy. Viral infections Flashcards
Pathogenesis of Rubella
mRNA virus; mild infection in adults.
Infected newborns shed the virus for many months; susceptible infants and adults are at risk.
fetal presentation of Rubella
-“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.
diagnosis of rubella in the fetus
presence in chorionic villi, amniotic fluid:
1. Rubella RNA
2. IgM antibody serology (Fetal blood can confirm fetal infection)
treatment for rubella infection
supportive
only prevention–>MMRV vaccine (live-attenuated; should be given at least 1 month before conception).
what is the most common cause of perinatal infection in the developed world?
cytomegalovirus (CMV)
how is CMV fetal infection transmitted?
via intrauterine, intrapartum, or postpartum infection (breastfeeding).
maternal presentation of CMV
- 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.
fetal presentation of CMV
- Intracranial calcifications.
- Chorioretinitis.
- Microcephaly, mental and motor retardation.
- Hemolytic anemia.
- Sensorineural deficits.
diagnosis of fetal CMV
- 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. - US can show microcephaly, ventriculomegaly, intracranial calcifications.
- PCR detects and quantifies viral DNA in amniotic fluid and fetal blood.
what treatment is given to maternal and fetal CMV infection?
*Potential maternal treatment: ganciclovir, valganciclovir, foscarnet, cidofovir.
*No specific fetal treatment, or prophylaxis.
how does a fetus contact HSV?
in the birth canal during delivery
presentation of HSV fetal infection
cutaneous lesions, CNS involvement (microcephaly, meningoencephalitis, seizures), chorioretinitis, blindness.
presentation of HSV maternal infection
genital herpes
multiple painful genital vesicles with an erythematous base that progress to painful ulcers; usually present 1-3 weeks after exposure.
treatment of HSV
Valacyclovir, acyclovir, famciclovir.
diagnosis of HSV
- 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.
how does varicella zoster virus (VZV) present in adults and pregnancy?
More severe in adults; even more severe in pregnancy (maternal pneumonia).
what are the fetal effects from VZV infection?
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.
diagnosis of VZV
presence of antibodies if immunity is uncertain
treatment for VZV
- 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).
is the Live-attenuated vaccine for VZV given to pregnant ane newborns
not recommended for pregnant women or newborns.
Not secreted in breast milk, so can give postpartum.
how do neonates get HBV infection?
Most neonatal infections are due to ingestion of infected fluid in the peripartum period or with breastfeeding;
a small percentage of transplacental transmission.
what antigen indicates there a high risk of infectivity?
↑ levels of HBeAg.
presentation of HBV in neonates
Chronic infection occurs in 70-90% of acutely infected infants leading to cirrhosis and
hepatocellular carcinoma.
when do we diagnose HBV infection of the pregnant women
Screen at the first prenatal visit and delivery with hepatitis B surface antigen (HBsAg).
how do we prevent neonatal infection if mother positive for HBsAg?
- Hepatitis B immunoglobulin (HBIG) given to infant upon delivery.
- Give first of three hepatitis B vaccines upon delivery.
The vast majority of cases of pediatric AIDS are?
secondary to vertical transmission from mother to fetus.
perinatal transmission is approx. 25%.
how can we reduce the risk of vertical transmission of HIV during pregnancy?
- 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 - HAART started in the antenatal period can reduce the risk of transmission to 2%.
- Reduce duration of ruptured membranes.
- Recommend cesarean delivery before labor if viral load > 1000 copies.
- Avoid breastfeeding.
when is HIV screening recommended ?
at the first prenatal visit.
Screening test (ELISA) followed by a confirmatory test (Western blot or PCR).
management of HIV pregnant women
- Antiretroviral therapy should be encouraged in all HIV-infected pregnant women regardless of CD4+ count and viral load to reduce vertical transmission.
- CD4+ counts and viral loads should be monitored at regular intervals.
- Blood counts and LFTs should be monitored monthly while the patient is on ZDV.
