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68 Cards in this Set
- Front
- Back
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Which immunoglobulin crosses the placenta IgM or IgG?
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IgG crosses the placenta
IgM does not cross (they are too big and therefore cannot provide immunity to foetus) |
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At what stage gestation does fetal cell mediated and humoral immunity in the foetus?
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9-14 weeks gestation
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At what stage gestation is a baby most susceptible to rubella?
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< 8 weeks - 90-100%
8-12 weeks - 50% 12-20 weeks - 20% > 20 weeks < 1% |
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What are the clinical features of a congenital rubella infection?
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eye lesions
cardiac lesions deafness mental retardation cerebral palsy hepatitis hepatosplenomegaly meningoencephalitis |
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What are the clinical features of a maternal rubella infection?
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generalised rash
cough fever conjunctivities arthralgia lymphadenopathy |
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How long should a woman wait after having the rubella vaccination before they fall pregnant?
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3 months
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Should a non-immune mum be administered the rubella vaccine while pregnant?
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NO. It is a live attenuated vaccine.
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If a mother gets varicella zoster during her pregnancy how should she be managed?
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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 |
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Which week of gestation has the biggest risk of fetal varicella?
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12-20 weeks gestation - 2%
< 12 weeks - 0.4% |
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What are some abnormalities that you see with fetal varicella syndrome?
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Skin scars
eye abnormalities limb abnormalities prematuriy low birthweight cortical atrophy mental retardation poor sphincter control early death |
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What time period close to birth are you worried about pregnant Mum getting chickenpox? What is the fetal infection rate at this time?
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5 days prior or 2 days after delivery
50% No time for antibodies to get passed on |
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How do you treat maternal chickenpox < 7 days before delivery?
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VZIG immediately to neonate < 24 hours after birth (can be given up to 72 hours)
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How do you treat maternal chickenpox 0-28 days after delivery?
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VZIG immediately to neonate < 24 hours after birth (can be given up to 72 hours)
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How do you treat maternal chickenpox developed in first or second trimester?
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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 |
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What is the most common cause of congenital infection?
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CMV
0.3-2% live births |
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Which infection that is of concern in pregnancy is usually asymptomatic?
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CMV
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What are some of the clinical features of fetal CMV?
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Microcephaly
Deafness ascites hydrops fetalis olido or polyhydramnios hydrocephalus IUGR intracranial calcification abdominal calcification |
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If a mother develops CMV during pregnancy what should be done?
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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 |
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What % of fetus's infected with primary CMV will have clinical disease?
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10-15%
These have a 90% risk of sequalae 90% of infants will have asymptomatic CMV - 10% of asymptomatic infants may develop sequelae (hearing loss) |
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What is the rate of materno-fetal transmission in primary infection?
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50%
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What is the risk that a fetus is infected if the Mum has non-primary CMV
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< 1% risk of transmission
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with non-primary CMV what is the risk of symptomatic and asymptomatic congenital CMV and sequelae?
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Symptomatic < 1%
Asymptomatic > 99% Risk of sequaelae up to 10% |
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How is toxoplasmosis usually acquired?
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Eating raw meat
Contact with soil contaminated with oocytes in infected cat faeces |
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Is toxoplasmosis in the mother usually symptomatic or asympatomtic?
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Usually asymptomatic
Can develop flu-like illness: fevers, malaise, lymphadenopathy, rash |
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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
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What are the features of a congenital toxoplasmosis infection?
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LBW
Hepatosplenomegaly Jaundice Anaemia Intracranial calcifications hydrocephalus Microcephaly Developmental delay Chorioretinitis |
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What treatment should be given to mothers with known toxoplasmosis?
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Antibiotic treatment may reduce the risk of fetal sequelae - treat with spiramycin or pyrimethamine/sulphadoxine with folinic acid
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What is syphillis caused by?
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Treponema pallidum
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At what stage of gestation can trepnoemes (syphillis) penetrate the placenta and infect the fetus?
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After the 15th week (second trimester)
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What are the consequences of congenital syphillus?
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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 |
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Treatment for maternal syphillus?
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Benzathine penicillin
Can prevent transmission to neonate and can be used to treat active neonatal infections |
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What screening tests are done for syphillus during pregnancy?
At what stage? |
VDRL - some false positives
TPHA - corrects for false positives |
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What causes parvovirus B19
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erythema infectiosum (fifth disease) - slapped cheek appearance
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Clinical maternal features of parvovirus
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often asymptomatic
red maculopapular rash (slapped cheek) arthralgia |
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Symptoms of congenital parvovirus?
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Abortion
Fetal death hydrops fetalis anaemia myocarditis |
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How do you confirm the diagnosis of parvovirus?
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maternal serology - IgM detectable within 1-3 weeks of exposure
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What is the risk of fetal loss associated with a first trimester symptomatic finection with parvovirus
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10%
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What is the risk of developing fetal hydrops for those infected with parvovirus during weeks 9-20 of gestation
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3%
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What is the management of maternal parvovirus?
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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 |
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What is listeria found in?
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Raw vegetables, milk, fish, poultry
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What are the maternal symptoms of listeria?
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sepsis, mild flu-like illness, fever, malaise, abdominal pain
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Is serology useful for the diagnosis of listeria?
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No it requires isolation of listeria monocytogenes
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What are the consequences of fetal infection with listeria?
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fetal death
prematurity |
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Management of listeria?
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penicillin
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which type of HSV infection caries the highest risk of neonatal infection?
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Primary infection (no seroconversion)
NB: if there is a primary infection (seroconversion before 34 weeks) the risk is < 3% |
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What are the 4 presentations of HSV and when do they present?
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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 |
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Diagnosis of maternal HSV
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PCR for herpes DNA in surface vesicle swabs, nasopharyngeal swabs, blood, CSF
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When should a caesarean section be performed with maternal HSV>
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Definiteily if primary infection at or near term (membrane rupture < 6 hours) OR consider if secondary infection with active lesions at delivery
+ suppressive aciclovir |
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Which form of delivery is used if secondary infection with HSV at delivery?
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Vaginal
Give aciclovir in the last 4 weeks to reduce recurrence |
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Management of nenoatal HSV>
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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 |
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When is neonatal HSV most commonly acquired?
Delivery or intrauterine |
Most commonly acquired at delivery
True intrauterine infection rare - spontaneous abortion, IUGR, preterm labour |
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How is perinatal transmission of HIV preventable?
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Antiretroviral prophylaxis
Caesarean delivery bottle feeding Reduces transmission from 30% to 2% |
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Is there a high risk of vertical transmission of Hep C?
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No
Transmission only occurs from mothers who have circulating HCV RNA 5-10% of infants will develop HCV infection |
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Can Hep C be transmitted via breast milk?
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Low to zero risk
All mothers with asymptomatic HCV infection should be allowed to breastfeed |
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When should infants be tested for HCV
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HCV RNA at 2-3 months and/or anti-HCV Ab at 18 months
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Should babies with HCV posivie mothers be delivered by caesarian section?
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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. |
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How should neonates with HCV be treated?
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Interferon alpha + ribavirin
Sustained viral clearance in up to 50% of patients |
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What organism is the commonest cause of neonatal sepsis?
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Group B strep
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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 |
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When does transmission of GBS occur?
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before or during labour
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Consequences of GBS infection?
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Ascending infection (with amniotic fluid and fetal infection) occurs during labour (sometimes with intact membranes)
--> stillbirth --> infant sepsis sometimes meningitis |
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Why are antibiotics given to all women in preterm labour?
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Prophylaxis against GBS
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When should a woman be screened for GBS?
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RPA - 28 weeks
US + lecture - 36 weeks |
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If a woman is positive for GBS at 36 weeks what management should she receive?
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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 |
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How do you manage maternal chickenpox developed third trimester < 5-21 days before delivery
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Observe
Make sure Mum doesn't develop pneumonia |
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If mother was recently exposed to chickenpox how do you manage it?
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If seronegative - give VZIG
If seropositive - do nothing |
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Which perinatal infections require treatment for the Mum, treatment for the baby
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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 |
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Which perinatal infections have a risk of preterm labour?
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Chickenpox
HIV Syphillus |
