perinatal infections Flashcards
how is toxoplasmosis transmitted?
ingestion
- cat feces
- undercooked meats
- insects in soil
for toxoplasmosis, what is the vertical transmission rate?
depends on trimester
1st tri: 15%, high severity
2nd tri: 30% intermediate severity
3rd tri: 60% mild severity
what are the two forms of toxoplasmosis?
it is an intracellular parasite
- trophozite = invasive
- cyst/oocyst = inactive
how is toxo diagnosed?
serologies, but these are notoriously poor
- IgM reflects acute infection
- IgG reflection immunity or prior infection (usually within a few weeks)
if both are negative but suspicion is high, then retestin 2-3 weeks
symptoms of toxoplasmosis
nonspecific generally, rarely viremia is possible
treatment for toxoplasmosis:
- MFM consult
- spiramycin acutely to prevent transplacental transfer
- if fetal infection: pyrimethamine, sulfadiazine, folinic acid
what are fetal effects/presentation of toxoplasmosis?
- intracranial calcification
- chorioretinitis
- hearing loss
- mental retardation
(all “head” problems) - hepatosplenomegaly
is there screening for toxoplasmosis?
only in immunocompromised women
how is cmv transmitted?
- sexual direct, or saliva contact
- incubation time 40 days, viremia in 2-3 weeks
what is prevelance of CMV? what is transmission rate? risk of neonatal disease?
- prevalence 3%. maternal immunity does not protect fetus.
- transmission rate increases by trimester (30->38->40%), overall 30%
- neonatal disease occurs in 30% (defined as s/s at birth and sequelae)
- risk of neonatal death 30% in affected neonates
- 65-80% have neuro morbidity
what are features of CMV infection for fetus?
- intracranial calcifications
- abdominal calcifications
- hepatosplenomegaly
- IUGR
- hydrops
- microcephaly (distinct from toxo)
*congenital hearing loss most common severe sequelae
2nd infection- risks negligible for fetus
5% fetuses exhibit congenital CMV
how do you diagnose CMV?
CMV IgG x2 taken 3-4 weeks apart
1) either it turns negative to positive
2) 4-fold increase in titer
fetal diagnosis:
- amniotic fluid PCR, better than Cx
- no correlation to infection severity
what is treatment for CMV
no approved meds
- antivirals for AIDS/transplant patients
- Ig’s are experimental
how is parvovirus transmitted?
- respiratory secretions
- hand to mouth
what is vertical transmission rate of parvovirus?
25%
what are possible fetal outcomes of parovirus?
- 1st trimester: SAB
- late 2nd trimester and 3rd trimester: hydrops and IUFD
hydorps only in 1% maternal infxns (erythrocyte p antigen required)
replicates in bone marrow - 10% of non-immune hydrops
what does parvovirus present like?
5-10 d after exposure, rash, arthritis, flu like symptoms
20% asymptomatic
how do you diagnose parovirus?
- ELISA PCR for IgG and IgM
- PCR is more sensitive
If known exposure and negative testing; retest in 3-4 weeks
Fetal infxn dx with amnio PCR
what is fetal survival?
- if treated: 80%
- if untreated: 20%
what is fetal surveillance with parvo?
for 2-3 months after exposure/mat infection, q1-2 week serial US for fetal wellbeing.
PUBS for anemia assessment severity
if no complications by 8-12 weeks, they are unlikely to occur
MCA dopplers are best predictor of fetal anemia
what are maternal effects of varicella/chickenpox?
- varicella PNA. 20% pregnant women. 5% mortality (tx with IV acyclovir, ICU admission).
- encphalitis - rare
- shingles = reactivation of latent virus (minimal fetal risk)
fetal effects of varicella
- IUFD
- SAB
- Varicella embryopathy: 2%, 13-20 weeks pretty much only risk
- -> skin scarring, limb hypoplasia, chorioretinitis, microcpehaly, mental retardation.
if before 13 weeks: malfromations uncommon, if after 20 weeks just skin contracture
when is the highest risk time of maternal infection for fetal mortality?
- < 5 days before delivery, and 2 days PP -> therefore give zoster PEppx
how do you diagnose varicella?
- clinical- hx, exposure/presence of rash
- PCR of vesicular or throat swab (confirmation of acute infection)
- ELISA for VZV IgM and IgG (latter good for immunity determination)
