Rarer Pathologies encountered in pregnancy Flashcards
What causes Chicken Pox?
- Caused by primary infection with varicella-zoster virus. Shingles is caused by reactivation of dormant virus in dorsal root ganglion.
What are the risks of chicken pox to the mother in pregnancy?
Risk to mother
- (5x ↑risk of pneumonitis)
Risk to foetus (can lead to FVS)
- Foetal Varicella syndrome (FVS)
- 1% risk following maternal varicella exposure if it occurs before 20 weeks gestation. Very small number of cases between 20-28 weeks gestation and none after 28 weeks
- Feature of FVS include skin scarring, microphthalmia, limb hypoplasia, microcephaly and learning disabilities
- Shingles in infancy: 1-2% risk if maternal exposure in the second or third trimester
- Severe neonatal varicella: if mother develops rash between 5 days before and 2 days after birth, there is risk of neonatal varicella, which may be fatal to the newborn child in around 20% of cases
How is Chickenpox Exposure managed in pregnancy?
If there is doubt about the mother previously having chickenpox, maternal blood should be urgently checked for varicella antibodies
- ≤20 weeks gestation not immune to varicella: Give varicella-zoster immunoglobulin (VZIG) asap. VZIG is effective up to 10 days post exposure
- >20 weeks gestation not immune to varicella: either VZIG or antivirals (aciclovir or valaciclovir) should be given days 7 to 14 after exposure
How is Chickenpox managed in pregnancy?
Specialist advice should be sought. Increased risk of serious chickenpox infection and fetal varicella risk balanced against theoretical concerns about the safety of aciclovir in pregnancy
- Consensus guidelines suggest oral aciclovir should be given if the pregnant women is ≥20 weeks and she presents within 24 hours of onset of the rash.
- If the woman is < 20 weeks the aciclovir should be ‘considered with caution’
What causes rubella in pregnancy?
- Viral infection caused by the togavirus.
- Rare with MMR vaccine.
- If contracted during pregnancy, there is a risk of congenital rubella syndrome. Incubation period is 14-21 days and individuals are infectious from 7 days before symptoms appear to 4 days after the onset of the rash.
What is the risk of damage to the foetus of rubella?
- In first 8-10 weeks risk of damage to foetus can be 90%. Damage is rare after 16 weeks
What are features of Congenital Rubella syndrome?
- Sensorineural deafness
- Congenital cataracts
- Congenital heart disease (e.g. patent ductus arteriosus)
- Growth retardation
- Hepatosplenomegaly
- Purpuric skin lesions
- ‘Salt and pepper’ chorioretinitis
- Microphthalmia
- Cerebral palsy
How is Rubella diagnosed in pregnancy?
- Suspected cases discussed immediately with the local Health Protection Unit (HPU)
- IgM antibodies are raised in women recently exposed to the virus
- Very difficult to distinguish rubella from parvovirus B19 clinically. It is important check parvovirus B19 serology also as there is a 30% risk of transplacental infection, with a 5-10% risk of fetal loss
How is Rubella in pregnancy managed?
- If no immunity, advised to keep away from people who might have rubella.
- Non-immune mothers should be offered the MMR vaccination in the post-natal period.
- MMR vaccines should not be administered to women known to be pregnant or attempting to become pregnant
What are risks of GBS in pregnancy?
- Most common causes of early-onset severe infection in neonatal period.
- Infant exposed to maternal GBS during labour and can subsequently develop potentially serious infection
- Around 20-40% of mother have GBS present in their bowel flora and therefore be thought as carriers of GBS.
What are risk factors of GBS infection?
- Prematurity
- Prolonged rupture of the membranes
- Previous sibling GBS infection
- Maternal pyrexia e.g., secondary to chorioamnionitis
How is GBS investigated in pregnancy?
- Women who’ve had GBS detected in a previous pregnancy should be informed that their risk of maternal GBS carriage in this pregnancy is 50%.
- Should be offered intrapartum antibiotic prophylaxis (IAP) OR testing in late pregnancy and then antibiotics if still positive
- Swabs for GBS this should be offered at 35-37 weeks or 3-5 weeks prior to the anticipated delivery date if required
When is IAP offered in pregnancy and what antiobiotic is used?
Benzylpenicillin is the antibiotic of choice for GBS prophylaxis. IAP should be offered to:
- Women with a previous baby with early- or late-onset GBS disease.
- Women in preterm labour regardless of their GBS status.
- Women with a pyrexia during labour (>38ºC)
What are predisposing factors for aortic dissection in pregnancy?
- Hypertension
- Congenital heart disease
- Marfan’s syndrome
Mainly Stanford type A dissections
What are clinical features of Aortic Dissection?
- Sudden tearing chest pain, transient syncope
- Patient may be cold and clammy, hypertensive and have an aortic regurgitation murmur
- Involvement of the right coronary artery may cause inferior myocardial infarction
