Obstetrics and perinatal infections Flashcards
How are UTIs different in pregnant women
May be asymptomatic
May lead to pyelonephritis (may ascend to kidneys)
How does varicella differ in pregnant women
May be much more severe. More likely to die of varicella pneumonia
Most important causes of congenital infections
Cytomegalovirus (most common) Rubella Toxoplasmosis Syphilis Varicella Zika
Consequence of cytomegalovirus
Only a small minority have severe consequences (cataracts, sensory neural deafness and cataracts)
minor consequences- unilateral deafness
How does baby get cytomegalovirus infection
From mother. May be primary or secondary. CMV is a herpesvirus so exhibits latency
When is risk of damage to baby greater when mother is infected with CMV
IF this is her very first infection as she doesn’t have antibodies
What is maternal infection of CMV like
Mostly always asymptomatic
IF a pregnant woman develops a rash, what do you need to do and why
Must exclude maternal rubella- because there is a risk of congenital rubella syndrome
How do foetuses get congenital rubella
Transplacental trasmissione to fetus
What is the outcome of congenital rubella dependent on
Timing within pregnancy. Whether it is in:
- First trimester
- 12-18 weeks
- After 18 weeks
What is the risk of congenital rubella if acquired in first trimester
Multiple developmental defects including CNS, cataracts, heart
What is the risk of congenital rubella if acquire in 12-18 weeks
What is the risk of congenital rubella if acquired after 18 weeks
Most likely
Deafness
-NO risk
How is congenital rubella preventable
Universal MMR vaccination
Antenatal screening and postpartum vaccination
Investigation of all maternal rash and maternal contact with rash
What is a maternal rash more likely to be and what is the consequence of this
Parvovirus B19 infection
- Increased risk of spontaneous miscarriage
- Can cause fatal hydrops
Transmission of congenital toxoplasmosis and when does the risk increase
transmission during maternal infection- risk increases with duration of pregnancy
What does congenital toxoplasmosis lead to
Brain damage, chloroido-retinitis
How do we check for syphilis to stop congenital syphilis
Routine antenatal screening and treatment
What can congenital varicella lead to
Skin loss, scarring, usually unilateral, segmented
Impaired limb bud development
Many other, less specific features e.g. microcephaly, cataracts, IUGR
What is Zika virus reported with a rise in
Microcephaly (where baby’s head is much smaller than expected)
Blood-borne virus infections
HIV
Hep B virus
Hep C virus
How can blood-borne virus transmission occur to baby
Antenatally- Transplacental
Perinatally-INfected birth canal, exposure to maternal blood
Postnatally- In breast milk (HIV only
How to prevent mother to baby HIV
Maternal antiretroviral therapy to reduce viral load
Elective (planned) caesarian section
No breast feeding
How to prevent mother to baby hep b
Preventable by vaccination
Difference in management between Hep b and Hep c management
Hep b can be treated so is screened for however there is no intervention for hep c so there is no rationale for screening
What are some other neonatal infection
Neonatal septicaemia/meningitis
Neonatal varicella
Neonatal herpes
Opthalmia neonatorum
Principal causes of neonatal septicaemia/meningitis
Streptococcus
E.Coli
(less common: listeria monocytogenes)
How is neonatal septicaemia acquired
From maternal birth canal/ early rupture of membranes leading to chorioamnionitis
[for listeria monocytogenes, maternal infection is food borne (e.g. soft cheese) , organism resides in GI tract]
What does Group B streptococcus cause in pregnant women and how is it acquired
Neonatal pneumonia, septicaemia, meningitis
Colonises perineum/vagina in around 1/4 pregnant women. IT is commonly found as normal GI flora
How can a Group B streptococcus infection be managed
IV antibiotics during delivery reduces risk of neonatal infection
Risk of maternal varicella in late pregnancy
Baby can be born with chicken pox and mortality rate is high
Maternal chicken-pox in late pregnancy management
What drugs can you use
- How long does it take for maternal antibodies to develop and cross the placenta?
- If she goes into labour for at least 7 days after her rash appears, then it will not get life threatening varicella
If tha baby is born within 7 days of onset of maternal rash, then you would give the baby passive immunity through varicella immunoglobulin
Can use prophylactic aciclovir when baby is born
How are most neonatal herpes infections acquired
Primary maternal genital herpes
Why is neonatal herpes difficult to diagnose
What is the prognosis for neonatal herpes
50% cases have internally disseminated infection without external lesions
-Prognosis is bad. Need to treat as soon as possible
Organisms that cause ophthalmia neonatorum (conjunctivitis) and how is it acquired
Gonorrhoea or chlamydia
Infected maternal birth canal
