perinatal infections Flashcards
what is the difference between intrauterine infections and perinatal infections?
intrauterine=infection acquired/carried by the mother and transmitted to the developing fetus
whereas perinatal infections occur around the time of delivery
when do we worry about chickenpox in pregnancy?
- severe maternal varicella during pregnancy causing maternal pneumonia!!
- infection in the 2nd and 3rd trimester of pregnancy–> congenital varicella syndrome
- perinatal infection around delivery
what are some complications of influenza in pregnancy?
primary viral pneumonitis
and secondary bacterial pneumonia
premature birth
what is the leading cause of neonatal sepsis?
GBS (group b strep)
how might a baby be colonised by GBS?
ascending infection
colonised during delivery (vertical transmission)
what is the clinical presentation of early onset GBS disease as compared to late onset GBS infection?
pneumonia, septicaemia and less commonly meninigitis in early onset GBS
meningitis and septicaemia much more prevalent in late onset GBS
which antibiotic do we use for maternal prophylaxis of GBS infection?
benzylpenicillin
or if there is an allergy to penicillin you can try clindamycin, vancomycin or cefazolin
what are the maternal risk factors for EOS GBS?
Preterm labour Early rupture of membranes Maternal fever Clinical diagnosis of choriamnionitis A previous infant with GBS GBS bacteriuria during current pregnancy
when do we do GBS screening during pregnancy and how?
35-37 weeks gestation
via vaginal and anal swabs
when do we give prophylactic intrapartum antibiotics for GBS for a high risk pregnancy?
4 hrs prior to delivery and every 4 hrly until delivery
what antibiotics do we use for neonates with GBS sepsis?
benzylpenicillin + gentamicin
how might hep b be transmitted to infants?
vertically (mum to baby during delivery) and horizontally
if you have a pregnant lady with surface antigen positivity for hep B and high viral load (eAg positive), what is the risk of vertical transmission of hep B? How might we reduce this risk?
Treat mother with lamivudine during pregnancy to reduce viral load
90% risk of vertical transmission
Hep B vaccine ( then at 2,4,6months) and HBIG at birth
give Aciclovir to the mother
how might we prevent vertical transmission of hep B
Hep B vaccine and immunoglobulin within 12 hrs post birth
the baby then receives HBV vaccine at 2, 4, 6 months according to the routine immunisation schedule
Check the baby’s serology at 12 months
do we screen all pregnant women for hep C?
according to RANZCOG- we screen all pregnant women
However, the national hep C testing policy advises selective screening based on risk factors bc of the following reasons:
- very low prevalence rate of hep c in Australia
- increased false positivity rate
- treatment for HCV are contraindicated in women- no studies available regarding safety of anti-hep c antiviral agents
what are the adverse effects of parvovirus in patients with thalassaemia or sickle cell disease?
acute life threatening red cell aplasia
how might we ix parvovirus?
maternal serology looking for seroconversion
invasive PCR analysis of amniotic fluid
if we have confirmed fetal parvovirus infection, what is our management?
serial u/s monitoring every 2 weeks for 6-12 weeks
any signs of fetal anaemia warrants intrauterine transfusion
what is the most diagnostic clinical examination feature of maternal rubella infection?
cervical lymphadenopathy at the back of the neck (occipital, post-auricular etc)
if you see this–> consider doing maternal serology
what is the classic triad of congenital rubella syndrome?
Think HEAD
Heart- PDA, PA stenosis
Eyes- cataracts, glaucoma, retinopathy
Audiology- sensorineural conductive hearing loss
= Deafness
A mother on her first antenatal visit is found to be seronegative for rubella (titre levels are low). what do you do to protect them?
give rubella vaccine in the postpartum period
from which viral family does the VZV virus arise?
herpesviridae family
how is VZV spread?
through respiratory droplets and direct contact
who do we give prophylactic IVIG to and when?
Prophylactic VZIG is given post exposure, up to 96 hours to susceptible pregnant women, immunocompromised, perinatal varicella infants, premature babies
how might we confirm whether a fetus is infected with CMV?
testing of the amniotic fluid–> via PCR
or testing the fetal cord blood
note that if CMV is confirmed, these tests can’t determine whether the baby is affected/damaged (e.g. need to do a serial u/s for this)
what is the percentage of babies who are infected with CMV in utero who have symptomatic infection at birth?
10%
what is our management of symptomatic CMV infected babies at birth?
confirm dx with urine looking for CMV
cranial u/s
multidisciplinary approach
- developmental paediatrician
- +/- speech path, OT, PT
- audiometry, visual assessments
what is our management of ASYMPTOMATIC CMV infected babies at birth?
For the 90% of asymptomatic CMV babies:
Serial audiometry, serial visual assessments, monitor for developmental delay and pneumonitis
what antiviral do we use for symptomatic CMV infection
ganciclovir +/- valganciclovir
when is the fetus at highest risk of congenital rubella syndrome?
first trimester
the earlier the gestation period, the more likely
what is the main fetal outcome of congenital syphillis?
stillbirth (40%)
when do we screen antenatally for syphilis in pregnancy?
routine screen at 1st antenatal visit
secondary screening at 28-32/40 weeks gestation and at delivery in high risk women
what are some clinical manifestations of congenital chlamydia?
conjunctivitis
pneumonia
what is the antibiotic regimen for chorioamnionitis?
- amoxycillin/ampicillin 2 g intravenously 6-hourly plus
- gentamicin 5 to 6 mg intravenously 24-hourly for three doses (if normal renal function) plus
- metronidazole 500 mg 8-hourly.
what is the risk of parvovirus in pregnancy and how do we monitor it?
pregnancy loss
hydrops due to anaemia
-monitor with MCA ultrasounds measuring the peak systolic velocity
how do we manage HSV lesions during pregnancy and in the intrapartum period?
Give analgesia
Give oral acyclovir to the mother
Perform caesarean section if active infection at the time of delivery to reduce maternal-fetal transmission
what are some management practice points for pregnant women with known HIV?
Anti-retrovirals to reduce viral load
-zidovudine
Elective caesarean section 38-39 weeks
Avoid breastfeeding (in developed countries only)
Baby is followed up and has antiretroviral treatment after birth
-don’t give vitamin K and hep B vaccination right away
which perinatal infections cause congenital abnormalities?
Cytomegalovirus • Parvovirus B19 • Rubella • Toxoplasma gondii • Treponema pallidum (syphilis) • Varicella zoster virus
what is the main risk of CMV perinatal infection?
sensorineural hearing loss
when is the risk of fetal infection and damage greatest secondary to rubella infection?
first 8 weeks in utero
when is the risk of fetal infection greatest secondary to parvovirus?
highest transmission between 8-20 weeks. (least likely during first trimester and 3rd trimester)
what should a pregnant woman do if she has symptoms of the flu?
If your GP suspects that you have the flu they may prescribe antiviral medications (such as Relenza or Tamiflu). These should be commenced in the first 2 days of the illness to have the greatest benefit.
GPs do not routinely test everyone with flu-like symptoms. However, because you are pregnant your doctor may decide to test you. This will involve collecting a nose and throat swab to look for the virus.
Women who are near term (>38 weeks gestation) or those with pregnancy complications may need to be admitted to hospital.
