Infectious disease in Pregnancy Flashcards
What antenatal inectious disease screening tests should be routinely conducted?
- HBV / HCV
- HIV
- Rubella (Abs)
- Syphilis (TPHA / TPPT)
- Chlamydia (urine PCR / swab)
- GBS
- Asymptomatic bacteriuria
- VZV (Abs)
What are the routes of transmission?
- Transplacental
- Intrapartum
- Postpartum
Intervention if maternal HBsAg +ve?
Administer HepB immune globulin (HBIG) and vaccine to infant at birth (prevents carriage in 95%)
Syphilis maternal +ve intervention?
Treat with penicillin and consult with STI specialist
HIV maternal +ve intervention?
- Antiretroviral therapy for mother and infant
- greatly reduces vertical transmission
- consult HIV specialist
Chlamydia +ve intervention?
-Treat woman and sexual partners to prevent intrapartum transmission
HCV maternal +ve, child intervention?
Follow up infant for infection at 12 months; treat mother
Intervention if mother GBS +ve?
Intrapartum chemoprophylaxis to prevent neonatal GBS infection
Rubella virus family?
Togavirus
Rubella virus genus?
Rubivirus
Rubella virus structure?
ssRNA, enveloped
What is the reservoir for the rubella virus?
Humans only reservoir
When does rubella peak?
Winter - spring
How is rubella transmitted?
Droplet and direct contact
Rubella incubation period?
14 - 23 days
When is virus present in relation to rash?
7d before to 14d after
Clinical features of rubella?
- Mild or asymptomatic
- Generalised maculopapular rash
- Generalised lymphadenopathy
- Low grade fever
- Polyarthralgia
What are the features of congenital rubella syndrome?
Neurobiological fx: -meningoencephalitis -behavioural -mental retardation -deafness Other fx: -blueberry muffin rash -thrombocytopenia -radiolucent bone disease -congenital heart disease (i.e. PDA) -cataracts
When is risk of damage by rubella virus greatest?
Rubella prevention?
-Screen antepartum
-Vaccinate if -ve (or post partum if pregnant)
No Rx for pregnant woman infected with rubella.
Which syphilis stage is most likely to result in congenital syphilis?
Primary (90%) transmission.
- early latent 40%
- late latent
Features of congenital syphilis?
- Stillbirth
- Hepatosplenomegaly / LAD
- Snuffles
- Osteochondritis syphilitica
- Hutchinson’s teeth
- Hereditary gumma
What are the non-treponeal tests?
VDRL, RPR
Ig to cellular lipids and lecithin
Positive 4-8/52 post infection
What are the treponemal tests?
TPHA, TPPA, FTA-Abs
- positive slightly earlier
- positive for life
- don’t reflect disease activity
What is the most valuable marker for congenital syphilis?
IgM (90% cases positive)
What is the structure of HBV?
dsDNA virus with glycolipid envelope
What is the most important determinant of HBV transmission?
HBeAg status of the mother
HBIG efficacy?
If given with 2-12h of delivery = 95%
What determines risk of maternal foetal HIV transmission?
- Viral load and CD4 count
- Duration of ruptured membranes (4h)
- Mode of delivery
Management of HSV during pregnancy?
- Primary infection at term: LUSC and acyclovir
- Recurrent lesions at term: LUSC
what is the optimum approach for detection of GBS?
- Low vaginal + anal swab
- self collected at 35-37w gestation
- cultured in selective broth
What are the features of congenital varicella syndrome?
First trimester primary infxn
- limb hypoplasia
- dermatomal scarring
- microcephaly
- cataracts
- GIT/GUT abnormalities
When is risk greatest for VZV congenital syndrome?
13-20 weeks = 2%
When is acyclovir given during pregnancy?
Prophylaxis for significant exposure:
- VZIG not given (i.e. >96h)
- T3 / 2nd half pregnancy
- Chronic lung disease
- immunosuppression
- cigarette smoking
When is VZIG given?
Given post exposure (
What is VZV vaccine and when given?
Live attenuated virus given at 12 months of age (MMR-V).
Why is GBS screening important?
50% of exposed infants will become colonised; 0.2/1000 will develop GBS sepsis
How does early onset GBS manifest in the infant?
Septicemia and shock, pneumonia or meningitis in first week of life
What are the signs of congenital toxoplasmosis?
- severe mental retardation
- chorioretinitis
- blindness
- epilepsy
- intracranial calcifications
- hydrocephalus
Counselling re toxoplasmosis infection prevention?
- throughly cook meats
- wash hands after handling raw meats
- wash fruits and veggies of soil
- wear gloves if working with soil
- keep cats indoors and feed processed foods
Parvovirus consequences for foetus?
-Spontaneous abortion
-foetal non immune hydrops
-death
If hydrops doesn’t develop, long term outcomes good.
Are pregnant women immunocompromised?
No. Although pregnancy complex situation where two immunologically different individuals coexist, not achieved through maternal immunosuppression. Infection (pneumonia, pyelonephritis) may be more severe however this is due to anatomic and physiologic changes rather than immunosuppression.
Why are infections in pregnancy important?
- Maternal morbidity and mortality (e.g. pneumococcal pneumonia)
- Harm to foetus (e.g. toxo etc)
What neonatal conditions are caused by GBS?
Two different entities: early onset infection (septicaemia) and late onset disease (usu meningitis). More common in preterm infants.
Which genital infections are implicated in preterm birth?
-Bacterial vaginosis
-Trichomonas
-Gonorrhoea
-Chlamydia
(last 3 inconsistently associated)
Should pregnant women be screened for CMV antibodies?
No. Most women have antibodies, usually represent prior disease. Even in cases of suspected infection, have limited value.
How should women with active HSV be delivered?
C section if active at time of delivery
Can VZV infection be prevented?
- Vaccinate non immune individuals
- Cannot vax during pregnancy
- VZIG to susceptible individuals with viral exposure
- Can give VZIG to exposed pregnant women; also protects foetus
Can anti-retroviral therapy be used in pregnancy?
Vertical transmission related to viral load. Antiviral therapy reduces viral load; therefore pregnant women should be offered medical therapy even if relatively low disease burden (CD4 counts and viral load). Usually multi drug therapy
How can HIV vertical transmission be reduced?
-1. Medical therapy during pregnancy
-2. If viral load greater 1000/mL; C section
-3. Should not breastfeed
Reduces transmission to less than 5%
How does HSV affect pregnancy?
- Relatively common genital infection; only risk to foetus if active disease at delivery
- neontal disease: asymptomatic infection - disseminated disease and death
