Chickenpox_Exposure_in_Pregnancy_Flashcards

Question 1

What causes chickenpox and shingles?

Answer 1

Chickenpox is caused by primary infection with varicella-zoster virus, and shingles is caused by reactivation of the dormant virus in the dorsal root ganglion.

Question 2

What is the risk to a pregnant woman if she contracts chickenpox?

Answer 2

There is a 5 times greater risk of pneumonitis in pregnant women with chickenpox.

Question 3

What is the risk of fetal varicella syndrome (FVS) following maternal varicella exposure?

Answer 3

The risk of FVS is around 1% if exposure occurs before 20 weeks gestation.

Question 4

Are there any cases of FVS occurring between 20-28 weeks or after 28 weeks?

Answer 4

A very small number of cases have been reported between 20-28 weeks, and none following 28 weeks.

Question 5

What are the features of Fetal Varicella Syndrome (FVS)?

Answer 5

Features include skin scarring, eye defects (microphthalmia), limb hypoplasia, microcephaly, and learning disabilities.

Question 6

What is the risk of shingles in infancy if the mother is exposed in the second or third trimester?

Answer 6

There is a 1-2% risk of shingles in infancy.

Question 7

When is there a risk of severe neonatal varicella?

Answer 7

If the mother develops a rash between 5 days before and 2 days after birth, there is a risk of neonatal varicella, which may be fatal to the newborn in about 20% of cases.

Question 8

What should be done if there is doubt about the mother previously having chickenpox?

Answer 8

Maternal blood should be urgently checked for varicella antibodies.

Question 9

What is the current first choice of PEP for pregnant women?

Answer 9

Oral aciclovir (or valaciclovir) is now the first choice of PEP for pregnant women at any stage of pregnancy.

Question 10

When should antivirals be given after exposure to chickenpox?

Answer 10

Antivirals should be given at day 7 to day 14 after exposure, not immediately.

Question 11

Why wait until days 7-14 to administer antivirals?

Answer 11

A study found that the incidence and severity of varicella infection were significantly higher in those given aciclovir immediately after exposure compared to those who started aciclovir at day 7.

Question 12

What should be done if a pregnant woman develops chickenpox?

Answer 12

Specialist advice should be sought due to the increased risk of serious chickenpox infection and fetal varicella risk.

Question 13

What do consensus guidelines suggest for pregnant women ≥ 20 weeks who develop chickenpox?

Answer 13

Oral aciclovir should be given if the woman presents within 24 hours of the onset of the rash.

Question 14

What is the recommendation for pregnant women < 20 weeks who develop chickenpox?

Answer 14

Aciclovir should be ‘considered with caution.’

Question 15

summarise chicken pox

Answer 15

Chickenpox exposure in pregnancy

Chickenpox is caused by primary infection with varicella-zoster virus. Shingles is caused by the reactivation of dormant virus in dorsal root ganglion. In pregnancy, there is a risk to both the mother and also the fetus, a syndrome now termed fetal varicella syndrome

Risks to the mother
5 times greater risk of pneumonitis

Fetal varicella syndrome (FVS)
risk of FVS following maternal varicella exposure is around 1% if occurs before 20 weeks gestation
studies have shown a very small number of cases occurring between 20-28 weeks gestation and none following 28 weeks
features of FVS include skin scarring, eye defects (microphthalmia), limb hypoplasia, microcephaly and learning disabilities

Other risks to the fetus
shingles in infancy: 1-2% risk if maternal exposure in the second or third trimester
severe neonatal varicella: if the mother develops rash between 5 days before and 2 days after birth there is a risk of neonatal varicella, which may be fatal to the newborn child in around 20% of cases

Management of chickenpox exposure in pregnancy, i.e. post-exposure prophylaxis (PEP)
if there is any doubt about the mother previously having chickenpox maternal blood should be urgently checked for varicella antibodies
historically, exposure has been managed through the timely administration of varicella zoster immunoglobulin (VZIG). However, the guidance has changed due to a national/international VZIG shortage. This was initially a short-term deviation from practice in 2022 but has now become baked into longer-term guidance
oral aciclovir (or valaciclovir) is now the first choice of PEP for pregnant women at any stage of pregnancy
antivirals should be given at day 7 to day 14 after exposure, not immediately
why wait until days 7-14? From the PHE guidelines: ‘In a study evaluating the comparative effectiveness of 7 days course of aciclovir given either immediately after exposure or starting at day 7 after exposure to healthy children, the incidence and severity of varicella infection was significantly higher in those given aciclovir immediately (10/13 (77%) who received aciclovir immediately developed clinical varicella compared with 3/14 (21%) who started aciclovir at day 7)’

Management of chickenpox in pregnancy
if a pregnant woman develops chickenpox in pregnancy then specialist advice should be sought
there is an increased risk of serious chickenpox infection (i.e. maternal risk) and fetal varicella risk (i.e. fetal risk) balanced against theoretical concerns about the safety of aciclovir in pregnancy
consensus guidelines (Health Protection Authority and RCOG) suggest oral aciclovir should be given if the pregnant women is ≥ 20 weeks and she presents within 24 hours of onset of the rash
if the woman is < 20 weeks the aciclovir should be ‘considered with caution’

Question 16

A 27-year-old pregnant woman at 18 weeks gestation presents to your clinic with her son, who has a fever and a rash suggestive of chickenpox. She cannot recall if she had chickenpox during her childhood and had one dose of chickenpox vaccine 7 years ago. Her pregnancy has been uncomplicated, and she currently exhibits no signs of fever or rash.

What is the most appropriate next step in the management of this woman?

Give prophylactic human varicella-zoster immunoglobulin
Give prophylaxis antiviral therapy
Reassurance
Start antiviral treatment
Test for varicella-zoster immunoglobulin G antibodies

Answer 16

Chickenpox exposure in pregnancy - first step is to check antibodies
Important for meLess important
This patient, who is pregnant, has been significantly exposed to chickenpox. Given that she lacks a history of either chickenpox or shingles and has received only one dose of the varicella vaccine (whereas two doses are required for confirmed immunity), her susceptibility to chickenpox remains due to an unverified immune status. Therefore it’s important to determine whether she has immunity against varicella-zoster virus. This can be done by testing for varicella-zoster immunoglobulin G antibodies.

If she tests negative, indicating that she does not have immunity, there is an urgent need for consultation with a specialist regarding prophylactic antiviral treatment or administration of human varicella-zoster immunoglobulin.

Conversely, if antibodies are present, indicating immunity, reassurance can be provided and no further intervention is necessary, although safety netting should be in place should symptoms indicative of infection arise.

Starting antiviral treatment immediately is not recommended as the mother currently exhibits no signs of fever or rash which are symptoms of chickenpox. In cases where any pregnant woman presents with symptoms suggestive of chickenpox, prompt referral to an obstetrician is essential for consideration of antiviral therapy, as well as close monitoring of both maternal and fetal well-being, with hospital admission being a consideration as the term approach.

Question 17

A 27-year-old woman who is 22-weeks pregnant presents to the emergency department after noticing a vesicular rash on her torso this morning. Upon further questioning you ascertain that her 4-year-old son developed chickenpox last week and the patient does not remember if she has had the condition before. She appears comfortable at rest.

You perform serological testing for varicella zoster virus which shows the following:

Varicella IgM Positive
Varicella IgG Negative

Which is the most appropriate management?

IV aciclovir
No treatment required
Oral aciclovir
Varicella zoster vaccination
Varicella zoster vaccination + oral aciclovir

Answer 17

Oral aciclovir

Chickenpox exposure in pregnancy - if not immune give either oral antivirals

This patient has not had chickenpox in the past and has active varicella infection as suggested by the negative IgG and positive IgM serology results. Women who develop chickenpox during pregnancy should be treated with oral aciclovir 800mg 5 times a day for 7 days if >20 weeks pregnant.

The RCOG advises that only women who develop severe infection and are at high risk of complicated chickenpox should be referred to hospital for IV aciclovir. Patients should be hospitalised if they develop chest or CNS symptoms, a dense hemorrhagic rash, or are immunocompromised. These findings are not evident in this scenario as the patient appears well currently and therefore this is not the best management for this patient.

No treatment would be inappropriate as this would increase maternal risk of developing pneumonia, hepatitis and encephalitis. The foetus would also have a small increased risk of developing foetal varicella syndrome (FVS) which may cause skin scarring, eye defects, and neurological abnormalities.

Live vaccines should not be administered routinely to pregnant women due to the risk of foetal infection. Therefore, options that include giving the varicella zoster vaccination are incorrect.

Question 18

Melissa, a 27-year-old pregnant woman (gravidity 1, parity 0) currently 33+0, presents to the general practitioner (GP) with a new rash.

Melissa attended her 4-year-old niece’s birthday party 2 weeks earlier. Yesterday, she began to feel unwell with malaise and a loss of appetite. This morning, she also noticed a new itchy rash across her back and abdomen upon waking. She called her sister and learnt that one of her niece’s friends at the party was recently diagnosed with chickenpox. Melissa has not had chickenpox before.

On examination, Melissa has red papules across her back and abdomen. She is afebrile.

Based on the above information, what is the most appropriate management option?

Calamine lotion and antihistamine to relieve itch
Paracetamol to relieve pain
Oral aciclovir
Intravenous aciclovir
Zoster immunoglobulin

Answer 18

Oral aciclovir

Pregnant women ≥ 20 weeks who develop chickenpox are generally treated with oral aciclovir if they present within 24 hours of the rash

Melissa is a pregnant woman (33 weeks) with chickenpox. She has experienced prodromal symptoms with malaise and a loss of appetite prior to the onset of her rash. As she has presented within 24 hours of the rash, she can be treated with oral aciclovir.

IV aciclovir is generally not required for pregnant women in contact with chickenpox.

It is reasonable to recommend calamine lotion and antihistamine to relieve itch. However, given that Melissa is currently pregnant, she should also commence on antiviral medications.

While pain is a major feature of shingles, it is less of a feature in chickenpox. Furthermore, Melissa has not complained of pain. Recommending paracetamol is therefore not the best management option.

Zoster immunoglobulin is offered to pregnant women exposed to chickenpox in the first 20 weeks of their pregnancy. As Melissa is 33 weeks into her pregnancy, she would not fit under this category.