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68 Cards in this Set

  • Front
  • Back
Which immunoglobulin crosses the placenta IgM or IgG?
IgG crosses the placenta
IgM does not cross (they are too big and therefore cannot provide immunity to foetus)
At what stage gestation does fetal cell mediated and humoral immunity in the foetus?
9-14 weeks gestation
At what stage gestation is a baby most susceptible to rubella?
< 8 weeks - 90-100%
8-12 weeks - 50%
12-20 weeks - 20%
> 20 weeks < 1%
What are the clinical features of a congenital rubella infection?
eye lesions
cardiac lesions
mental retardation
cerebral palsy
What are the clinical features of a maternal rubella infection?
generalised rash
How long should a woman wait after having the rubella vaccination before they fall pregnant?
3 months
Should a non-immune mum be administered the rubella vaccine while pregnant?
NO. It is a live attenuated vaccine.
If a mother gets varicella zoster during her pregnancy how should she be managed?
If previous maternal chickenpox - no action required
If no history or uncertain - check serology - if seropositive - no action required
if seronegative - exposure < 96 hours - passive immunisation IVZIG; if exposure > 96 hours oral aciclovir if at risk i.e. 2nd half of pregnancy, underlying lung disease, immunocompromised, smoker
Which week of gestation has the biggest risk of fetal varicella?
12-20 weeks gestation - 2%
< 12 weeks - 0.4%
What are some abnormalities that you see with fetal varicella syndrome?
Skin scars
eye abnormalities
limb abnormalities
prematuriy low birthweight
cortical atrophy
mental retardation
poor sphincter control
early death
What time period close to birth are you worried about pregnant Mum getting chickenpox? What is the fetal infection rate at this time?
5 days prior or 2 days after delivery
No time for antibodies to get passed on
How do you treat maternal chickenpox < 7 days before delivery?
VZIG immediately to neonate < 24 hours after birth (can be given up to 72 hours)
How do you treat maternal chickenpox 0-28 days after delivery?
VZIG immediately to neonate < 24 hours after birth (can be given up to 72 hours)
How do you treat maternal chickenpox developed in first or second trimester?
No VZIG required
Counsel parents on < 2% risk of congenital infection - consider prenatal diagnosis with amniocentesis (viral culture and serology) and serial US
No special interventions even if baby has chickenpox at bbirth or very soon after
If very preterm infant born with chickenpox give aciclovir
What is the most common cause of congenital infection?
0.3-2% live births
Which infection that is of concern in pregnancy is usually asymptomatic?
What are some of the clinical features of fetal CMV?
hydrops fetalis
olido or polyhydramnios
intracranial calcification
abdominal calcification
If a mother develops CMV during pregnancy what should be done?
Maternal serology to confirm primary infection IgM +ve initially, repeat serology 2-4/52 if seroconversion or rise in IgG confirms recent primary infection
Diagnosis best achieved by fetal US and amniocentesis for PCR +/- fetal serology but +ve results do not predict any degree of fetal damage
BUT there is no specific treatment
What % of fetus's infected with primary CMV will have clinical disease?
These have a 90% risk of sequalae
90% of infants will have asymptomatic CMV - 10% of asymptomatic infants may develop sequelae (hearing loss)
What is the rate of materno-fetal transmission in primary infection?
What is the risk that a fetus is infected if the Mum has non-primary CMV
< 1% risk of transmission
with non-primary CMV what is the risk of symptomatic and asymptomatic congenital CMV and sequelae?
Symptomatic < 1%
Asymptomatic > 99%
Risk of sequaelae up to 10%
How is toxoplasmosis usually acquired?
Eating raw meat
Contact with soil contaminated with oocytes in infected cat faeces
Is toxoplasmosis in the mother usually symptomatic or asympatomtic?
Usually asymptomatic
Can develop flu-like illness: fevers, malaise, lymphadenopathy, rash
At what stage of the pregnancy is fetal infection more common with maternal toxoplasmosis?
At what stage is severe sequaelae more likely?
Fetal infection is more common if the maternal infection is later in pregnancy but less likely to have severe sequaelae
What are the features of a congenital toxoplasmosis infection?
Intracranial calcifications
Developmental delay
What treatment should be given to mothers with known toxoplasmosis?
Antibiotic treatment may reduce the risk of fetal sequelae - treat with spiramycin or pyrimethamine/sulphadoxine with folinic acid
What is syphillis caused by?
Treponema pallidum
At what stage of gestation can trepnoemes (syphillis) penetrate the placenta and infect the fetus?
After the 15th week (second trimester)
What are the consequences of congenital syphillus?
premature delivery
Intrauterine fetal demise
Subclinical infection
Congenital infection
Handicap 40%
Will occur in 70% of fetuses born to untreated mothers, 1-2% if adequately treated
Treatment for maternal syphillus?
Benzathine penicillin
Can prevent transmission to neonate and can be used to treat active neonatal infections
What screening tests are done for syphillus during pregnancy?
At what stage?
VDRL - some false positives
TPHA - corrects for false positives
What causes parvovirus B19
erythema infectiosum (fifth disease) - slapped cheek appearance
Clinical maternal features of parvovirus
often asymptomatic
red maculopapular rash (slapped cheek)
Symptoms of congenital parvovirus?
Fetal death
hydrops fetalis
How do you confirm the diagnosis of parvovirus?
maternal serology - IgM detectable within 1-3 weeks of exposure
What is the risk of fetal loss associated with a first trimester symptomatic finection with parvovirus
What is the risk of developing fetal hydrops for those infected with parvovirus during weeks 9-20 of gestation
What is the management of maternal parvovirus?
Check titres to determine causes of seroconversion
Monitor for fetal anaemia
- assessment of fetal movement
ulstrasound assessment of MCA blood flow
Anaemic fetus can be delievered if safe or given intra-uterine transfusion via long needle
What is listeria found in?
Raw vegetables, milk, fish, poultry
What are the maternal symptoms of listeria?
sepsis, mild flu-like illness, fever, malaise, abdominal pain
Is serology useful for the diagnosis of listeria?
No it requires isolation of listeria monocytogenes
What are the consequences of fetal infection with listeria?
fetal death
Management of listeria?
which type of HSV infection caries the highest risk of neonatal infection?
Primary infection (no seroconversion)
NB: if there is a primary infection (seroconversion before 34 weeks) the risk is < 3%
What are the 4 presentations of HSV and when do they present?
localised to skin or mucous membrane
generalised multiorgan involement (week 1 range 0-2 weeks)
localised to lung (pneumonitis (3-7 days)
meningoencephalitis (7-30 days)
NB: 80% of untreated localised disease will progress to diseeminated +/- CNS disease if untreated
Diagnosis of maternal HSV
PCR for herpes DNA in surface vesicle swabs, nasopharyngeal swabs, blood, CSF
When should a caesarean section be performed with maternal HSV>
Definiteily if primary infection at or near term (membrane rupture < 6 hours) OR consider if secondary infection with active lesions at delivery
+ suppressive aciclovir
Which form of delivery is used if secondary infection with HSV at delivery?
Give aciclovir in the last 4 weeks to reduce recurrence
Management of nenoatal HSV>
If high risk (i.e. maternal primary infection close to delivery or active HSV and vaginal birth) - surface swabs, investigations, commence on aciclovir, If baby deveops symptoms then LP and CNS imaging.
If low risk - collect surface swabs at 24 hours and review clinically
When is neonatal HSV most commonly acquired?
Delivery or intrauterine
Most commonly acquired at delivery
True intrauterine infection rare - spontaneous abortion, IUGR, preterm labour
How is perinatal transmission of HIV preventable?
Antiretroviral prophylaxis
Caesarean delivery
bottle feeding
Reduces transmission from 30% to 2%
Is there a high risk of vertical transmission of Hep C?
Transmission only occurs from mothers who have circulating HCV RNA
5-10% of infants will develop HCV infection
Can Hep C be transmitted via breast milk?
Low to zero risk
All mothers with asymptomatic HCV infection should be allowed to breastfeed
When should infants be tested for HCV
HCV RNA at 2-3 months and/or anti-HCV Ab at 18 months
Should babies with HCV posivie mothers be delivered by caesarian section?
There may be an advantage in delivery by caesarean if done prior to rupture of membranes
but other studies have not consintently shown a benefit of this.
How should neonates with HCV be treated?
Interferon alpha + ribavirin
Sustained viral clearance in up to 50% of patients
What organism is the commonest cause of neonatal sepsis?
Group B strep
What % of pregnant women will have a positive swab for GBS from the lower genital tract?
How many of these will have a baby colonsied with GBS?
How many of these will have a baby with septicaemia?
10-15% mothers with GBS
10% of these baby with GBS
10% of these baby with septicaemia
When does transmission of GBS occur?
before or during labour
Consequences of GBS infection?
Ascending infection (with amniotic fluid and fetal infection) occurs during labour (sometimes with intact membranes)
--> stillbirth
--> infant sepsis sometimes meningitis
Why are antibiotics given to all women in preterm labour?
Prophylaxis against GBS
When should a woman be screened for GBS?
RPA - 28 weeks
US + lecture - 36 weeks
If a woman is positive for GBS at 36 weeks what management should she receive?
intrapartum antibiotic prophylaxis
Penicillin or ampicillin 1g IV every 6 hours as soon as labour starts or membranes rupture
NB: RPA only does this for carrier mothers with labour < 37 weeks; prolonged rupture of membranes for > 12 or > 18 hours; intrapartum fever of > 37.5 or > 38
How do you manage maternal chickenpox developed third trimester < 5-21 days before delivery
Make sure Mum doesn't develop pneumonia
If mother was recently exposed to chickenpox how do you manage it?
If seronegative - give VZIG
If seropositive - do nothing
Which perinatal infections require treatment for the Mum, treatment for the baby
Chickenpox - maternal VZIG if seronegative and exposed and neonatal VZIG if Mum develops infection 5 days pre and 2 days post delivery, if neonate born with chickenpox - acyclovir
Syphillus, HIV and herpes - treat Mum
HBV - Neonate - HBIG and vaccine at birth
CMV, Toxo, rubella - NO treatment
Which perinatal infections have a risk of preterm labour?