Infections In Pregnancy including Chicken Pox GT13 Flashcards
(52 cards)
What percentage of pregnancies are complicated by VZV?
3 in 1000
What percentage of pregnant women infected with VZV develop varicella pneumonia?
10-20%
what percentage of people over 15yrs, in the UK, are positive for VZV IgG?
> 90%
after being vaccinated against varicella zoster, for how long should a woman avoid pregnancy. What should she do if she develops a post- vaccination rash?
1 month, after completing the 2 dose vaccine.
She should avoid pregnant women if she has a post-vaccination rash
if a woman has been exposed to chicken pox and then received VZIG, from what time period is she considered potentially infectious?
What if she did not receive VZIG, from when is she considered infectious?
from 8-28 days after exposure
if no VZIG; from 8-21 days after exposure
what is the definition of “significant contact” with chicken pox?
contact in the same room for 15 minutes or more, face-to-face contact or contact in the setting of a large open ward
for how long is chicken pox infectious?
Chickenpox is infectious for 2 days before the appearance of the rash and for the duration of
the illness while the skin lesions are active. It ceases to be infectious when the lesions have crusted over.
what are the main maternal risks of chicken pox in pregnancy?
pneumonia, hepatitis, encephalitis.
What is the mortality rate from varicella pneumonia?
Mortality from varicella pneumonia is 0-14%
when should oral acyclovir be given to women who develop chicken pox? after what gestation is considered safe?
What is the dose and duration?
PO acyclovir 800mg 5 times a day for 7 days for women who present within 24 hours of onset of rash. After 20/40 gestation
What symptoms may be considered as ‘severe’ chicken pox, warranting hospital assessment?
Respiratory symptoms,
photophobia, seizures or drowsiness,
haemorrhagic rash or bleeding, or a dense rash with or without mucosal lesions
What is the minimum ideal time between onset of chicken pox rash, and delivery
7 days
If sooner - also risk of haemorrhage/coagulopathy (thrombocytopenia/hepatitis)
which type of regional anaesthesia is considered safe in chicken pox, when delivering by caesarean section.
epidural- as the dura mater is not penetrated, however, larger bore of needle may transfer more virus to epidural space. Choose needle site free of lesions
True or false-
If chicken pox occurs in the first trimester, risk of spontaneous miscarriage is increased
FALSE. risk of miscarriage doesnt appear to be increased
What are the 4 main characteristics of Fetal Varicella Syndrome
- skin scarring in a dermatomal distribution;
- eye defects (microphthalmia, chorioretinitis or cataracts);
- hypoplasia of the limbs
- neurological abnormalities (microcephaly, cortical atrophy, mental retardation or dysfunction of bowel and bladder sphincters)
Does fetal varicella syndrome occur at the time of initial fetal infection?
No.
It results from a subsequent herpes zoster reactivation in utero.
Only occurs in a minority of infected fetuses.
If a woman develops chicken pox in pregnancy, when should she be referred to fetal medicine?
at 16-20 weeks, or 5 weeks after infection- for discussion and detailed USS
Does amniocentesis have a poor positive predictive value for detecting fetal damage from chicken pox?
Yes. poor positive predictive value, strong negative predictive value.
does VZV DNA detected in amniotic fluid have a high or low sensitivity for development of fetal varicella syndrome?
VZV DNA presnet in amniotic fluid has HIGH sensitivity and LOW specificit for development of FVS (Fetal varicella syndrome)
what percentage of babies are infected with chicken pox if the mother develops chicken pox 1-4 weeks before delivery?
50%
what percentage of babies exhibit clinical varicella if the mother develops chicken pox 1-4 weeks before delivery?
23%
What treatment is given to neonate if mother develops chickenpox within the period 7 days before to 7 days after delivery
VZV immunoglobulin +/- IV acyclovir
can women breastfeed with chicken pox?
yes. If they are well enough to do so. If there are lesions close to nipple, can express breast milk
If a varicella susceptible woman has been exposed to chicken pox, in what time frame should she receive VZIg
within 10 days
