Viral Infections In Pregnancy Flashcards
(45 cards)
What are the options for treatment from exposure to virus?
Prophylaxis- antivirals, passive immunisation ivig, preventative (active) immunisation
Post infection- treatment
What are the classical infections associated with foetal complications?
Toxoplasmosis Other- syphilus, parvovirus B19, varicella zoster Rubella Cytomegalovirus Herpes simplex virus (Influenza, HIV)
What diseases are women routinely screened for at booking?
Syphilus
Hep b surface antigen
HIV
Rubella- igG to determine immune status and need for post natal vaccination (for those who haven’t been vaccinated, can’t use MMR)
Why is antenatal serology done?
To determine need for antenatal therapy +/- neonatal vaccination (in case of hepb) to prevent vertical transmission.
Serum stored for 1 year
What other diseases are tests for in some centres?
Hep c
Toxoplasma
Varicella igG limited value in UK
CMV igM/igG
What is the clinical course of rubella?
Mild illness, during first 16 weeks can cause congenital rubella syndrome
16-20 weeks- minimal risk of deafness only
Beyond 20 weeks- no known risk
What is the classic triad for CRS?
Sensineural deafness
eye defects- cataracts, congenital glaucoma, pigmentary retinopathy
Congenital heart disease- pulmonary artery stenosis, PDA
Also: purpura, splenomegaly, microcephaly, mental retardation
UK cases- imported
How do we diagnose rubella?
Non specific illness associated with onset of disease: rash, arthralgia 0 to 5, and occipital lymphadenopathy -5 to 15 days
How can rubella be tested?
Suspect if unvaccinated
Serology may demonstrate rubella igM or seroconversion to rubella igG
Virus detection- PCR from throat swab or blood, often virus gone from blood when symptoms are there
How do we manage rubella?
No specific antiviral or prophylaxis demonstrated to be effective
Termination of pregnancy offered in cases of suspected CRS
How can rubella be prevented?
Prevention- universal MMR vaccination, give after delivery but before discharge if antenatal testing indicates susceptibility
What is the commonest infectious cause of developmental delay and congenital abnormalities 4 per 1000 births
CMV
Relationship between age of gestation and infection unclear
When is the greatest risk of primary CMV infection (reactivation and reinfection significant)
During pregnancy or shortly before conception
Seroprevalence- 30-95% worldwide, lower socio economic, rises with age
Lifelong infection, intermittent shedding via saliva and urine
How do we diagnose CMV?
Asymptomatic- mononucleosis like illness, rash, hepatitis
How do we diagnose in utero?
Growth restriction, hepatosplenomegaly, ventriculomegaly, cardiac defects, microcephaly, cerebral calcification
Serology: CMV IgM and seroconversion to igG
Virus: saliva, urine, blood, amniotic fluid - not done routinely. Risk
Congenital infection: urine, saliva PCR in first 21 days
What is the treatment for CMV?
No specific treatment available to prevent in utero transmission, TOP offered if poor prognosis
What is the avidity testing for CMV?
Low avidity- igM and igG may be detected
High avidity- strength of antibody. Affinity of antibody increases over time, B cell undergo maturation. If igG is of high avidity, suggests infection occurred more than 3 months ago
What is the risk of congenital infection in the non immune women for CMV?
Moderate at 40%
Vast majority are asymptomatic
Some will develop deafness however
If symptomatic at birth, they will have long term problems
What is the risk of congenital infection in those who have already had the infection ie recurrent infection?
Small at 1-2%
Most asymptomatic
What is the treatment for CMV?
Can’t give to mum- ganciclovir teratogenic
Antiviral treatment of infant may improve outcome
Key is recognition of infection
6 months of oral valganciclovir best for long term outcome
Preventative vaccine in development
How does HSV occur in pregnancy?
HSV 1- orolabial, 2 is genital, lifelong infection with reactivation and asymptomatic shedding
Disseminated HSV derived rarely in pregnant woman
How common is HSV congenitally or neonatal ly?
Congenital- very rare, infection occurs in utero, risk of fetal death and growth restriction, towards end of pregnancy
Neonatal- rare, same incidence of HSV 1 and 2
What are the 3 manifestations of HSV?
SEM: 30%
CNS: 10%
Disseminated: 60%
What are the routes of infection in pregnancy?
Direct contact during birth, risk increases if primary HSV in 3rd trimester, more viral shedding for longer period of time, maternal antibody may not develop straight away
Ascending infection if PROM
Transmission from orolabial HSV, kissing baby, parents, relatives, staff