GTG chicken pox

Question 1

What is the treatment for a non CP immune pregnant woman who has had significant exposure to CP?

Answer 1

post-exposure prophylaxis - aciclovir 7-14 days post exposure
VZIG 2nd line

Question 2

What are the maternal risks of varicella in pregnancy?

Answer 2

pneumonia, hepatitis, encephalitis, death

Question 3

How long is it infectious for?

Answer 3

24-48h before rash
Once lesions crusted/around 5 days after rash onset

Question 4

In which cases should you treat chicken pox infx in pregnancy

Answer 4

within 24 hours of onset of rash, >20w pregnancy
Consider treating if <20w
VZIG is not useful once chicken pox develops so don’t use if rash present after exposure

Question 5

When is risk of fetal varicella syndrome high?

Answer 5

Risk is 1% before 28w

Question 6

When should fetal medicine input be arranged?

Answer 6

16-20 weeks OR 5 weeks after infection

Question 7

How does chicken pox infx affect delivery timing?

Answer 7

Avoid delivery for 7 days after maternal rash to allow passive transfer of antibodies.

If infx in last 4 weeks of pregnancy then fetus at risk of varicella infection in newborn

Question 8

When should varicella IgG be tested?

Answer 8

After exposure, if there is no past history of chicken pox or in women from tropical country check VZV IgG in booking blood.

If VZV IgG <100 treat as not immune with post-exposure prophylaxis as above

Question 9

Characteristics of fetal varicella syndrome

Answer 9

skin scarring in dermatomal distribution
eye defects (cataracts, small eyes)
limb hypoplasia
caused by a subsequent herpes zoster reactivation in utero