Varicella in pregnancy Flashcards
how is varicella transmitted
repiratory droplets and direct contact with vesicular fluids
What is the incubation period
10-21 days Infectious 48hrs prior to rash infectious until vesicles crust over
Maternal VZV complicated how many pregnancies
2-3 per 1000
True or false ? shingles is not assoc w viremia and does not cause fetal sequale
TRUE
What is the maternal fatality rate by age group?
15-19 yo : 2.7 per 100 000 30-39 yo : 25.2 per 100 000
What usually causes maternal death
Respiratory complications; 5-10% will have pneumonitis
What are risk factors for varicella pneumonitis
Smoker More than 100 lesions
What is strongest correlate with maternal death
Onset of disease in 3rd trimester
What are fetal manifestations of varicella infection
Congenital varicella ( embryopathy) Neonatal varicella (no embryopathy) in 1st 10 days of life
What are manifestations of congenital varicella
Chorioretinitis Cerebral cortical atrophy Hydronephrosis Cutaneous and bony leg defects partial limb reduction
What are rate of fetal infection prior to 13 weeks and between 13-20 wks?
0.4% 2%
what is the risk of fetal congenital varicella in 1st, 2nd and 3rd trimester
0,7% 2% 0%
list US findings of congenital varicella
MSK abn (assymetric limbs, shortening of limbs, malformations)
chest wall deformation
intestinal and hepatic echogenic foci
IUGR
polyhydramnios
hydrops
demise
Ventriculomegaly
Hydrocephalus
microcephaly
polymicrogyra
Porencephaly
Congenital cataract
microphtalmos
What ar ethe 2 most common ocular lesions related to varicella
congenital cataracts
microphtalmos
When (what GA) is neonatal infection more likely to happen ?
5 days before delivery to 2 days after
(period when maternal IgG are formed and it too short to provide transplacental passive immunization to fetus)
When varicella zoster immune globulin is given to mother, what % of newborns still develop infection
What does the vaccine help reduce?
30-40%
Number of complications
What medication is given to mother to treat varicella ?
oral Acyclovir
(shown to reduce duration of fever and sx of varicella infection in immunocompromised children and immunocompetent adults if started within 24hrs of developmment of rash)
Who should be treated with antivirals?
Children at high risk
adults with substansive varicella infection ( more than 100 lesions)
and or respiratory co-factors
Pregnant women with varicella pneumonitis
(if levels warrants, give IV antiviral)
What is the definition of direct contact exposure, substansial expsure and brief contact expsoure, continuous exposure?
Direct contact that lasts an HOUR or longer with infectious person while indoors
SUbstantial exposure for hospital contacts ex: sharing hospital room with infectious patient or prolonged, direct, face-to-face contact with infectious person
Brief contact: brief contact with infectious person (ex : x-ray tech or hskg personel)
Continuous exposure: ex: living with household member who have varicella (at greatest risk for infection)
How is the varicella vaccine given ?
What is the seroconversion rate ?
Should termination of pregnancy be recommended if vaccinated durign pregnancy?
2 doses 4-8 weeks apart for children more than 13yp when no hx of varicella.
97%
Not recommended in pregnancy or within 1 month of pregnancy
NO; study of 362 vaccine-exposure with NO cases of congenital varicella syndromes or congenital malformation.
VZIG (Varicella zoster immunoglobulin) lowers infection rates if administered within how long after exposure ?
72-96 hrs after exposure
Protection with VZIG last how long ?
What is the indication of VZIG?
What is the dose of VZIG ?
3 weeks
to reduce maternal risks of varicella infection and its complications
125 units per 10kg IM, max dose 625units.
Recommended for all susceptible pregnant women.
What testing should be done if hx reveals no prior varicella infection and no varicella antibody testing in early pregnancy or previous vaccination, after an exposure ?
antibody testing with enzyme-linked immunosorben assay OR
Fluorescent antibody to membrane antigen
Should precede use of VZIG
What is most frequent adverse rx following VZIG ?
local discomfort at injection site (pain, redness, swelling) 1%
less frequent: GI sx, 0,2%
severe: angioneurotic edema & anaphylactic shock (less than 0,1%)
