Varicella Zoster in Pregnancy

Question 1

What is varicella zoster

Answer 1

Exclusively human ds-DNA virus
Incubation period 2-3 weeks
Varicella = primary infection in a non-immune host
Zoster = reactivation of latent VZV in the dorsal root ganglia and cranial nerves (shingles)

Question 2

How is VZV transmitted

Answer 2

Varicella:
Direct contact with lesions or through airborne spread from resp. droplets.
Cinical disease is a manifestation of the second viraemic phase of the virus (day 9)
The virus is detectable in the nasopharynx 1 to 2 days before the onset of rash, and patients are infectious at this time and up to 5 days until all lesions have crusted over
After initial presentation, the virus establishes lifelong latency in the cranial nerves and dorsal root ganglia
Varicella infection of the newborn can occur due to transplacental transmission, ascending infection from the vagina, or from direct contact with lesions during or after delivery.

Question 3

What is Ramsey-Hunt syndrome

Answer 3

reactivation of the varicella zoster virus in the geniculate ganglion of CNVII

Question 4

What are the risk factors for varicella and zoster

Answer 4

Varicella: 1-9yo, exposure, unimmunised, occupational
Zoster: >50, HIV, corticosteroid use, chemotherapy, malignancies

Question 5

What are the symptoms of varicella

Answer 5

Vesicular rash
- “Dew drop on a rose petal”
- Intensely pruritic
- First appears centrally (face, scalp, torso) before spreading to the extremities
- First macules→ fluid-filled vesicles
- Early lesions begin to scab over
Vesicles on mucous membranes (nasopharynx, conjunctiva, mouth and vuvla)
Fever, usually <38, but could be higher
Headache
Prodromal nausea, myalgia, anorexia, and headache
Sore throat

Question 6

What are the symptoms of zoster

Answer 6

Localised pain (burning, stinging, itching, tingling) to a dermatome (Thoracic/trigeminal)
Pain may precede rash by days/weeks
Pruritic rash:
- Erythematous maculopapular → clear vesicles → pustulates → crust
Corneal ulceration → pain and reduced vision
Fever
HEadache
Prodromal malaise/fatigue
Pain without rash

Question 7

What investigations should be done for varicella zoster

Answer 7

Clinical diagnosis

Bedside: swab of vesicle for PCR or direct fluorescent antibody testing (DFA), Tzanck smear
Bloods: latex agglutination, ELISA, complement fixation

Question 8

What investigations should be done for varicella zoster exposure in pregnancy

Answer 8

Latex agglutination: Positive for Ig varicella
ELISA: Positive for Ig varicella
Complement fixation: Positive IgG for varicella

Other: US to screen for congenital varicella

Question 9

What is the criteria for a low risk of chickenpox infection after exposure

Answer 9

NOT immunocompromised AND:
Definite Hx of chickenpox/shingles
OR
2x doses of varicella containing vaccine

Question 10

What is the management for exposure to varicella zoster in pregnancy

Answer 10

Guidelines: immunisation against infectious disease: the ‘Green book’
Low risk: no treatment required
Unknown risk → test for VZ Ig
- Abs present: re-assure
- Abs not present:
→ <20weeks: VZIG asap (effective up to 10 days exposure)
→ >20 weeks: VZIG OR antivirals (aciclovir)7-14 days post exposure

Question 11

What is the treatment for varicella infection in pregnancy

Answer 11

Seek specialist advice (increased risk of serious infection and foetal varicella syndrome
Oral aciclovir (>20w gestation and within 24 hours of rash onset)
Consider aciclovir if <20w
Conservative: adequate fluids, smooth cotton fabrics, keep nails short, avoid contact with others at risk, paracetamol or topical calamine lotion

Question 12

What are the features of foetal varicella syndrome

Answer 12

Skin scarring in a dermatomal distribution
Eye defects e.g. microphthalmia, chorioretinitis, cataracts
Hypoplasia of the limbs
Neurological abnormalities e.g. microcephaly, cortical atrophy, learning difficulties, bowel or bladder sphincter dysfunction

Question 13

What are the complications of varicella in pregnant mothers

Answer 13

Varicella pneumonia → encephalitis, hepatitis
Severity increases with gestation

Question 14

What is the prognosis for varicella zoster in pregnancy

Answer 14

Infection <4 weeks before delivery → 1/2 babies infected, 1/4 develop FVS
Maternal infection 20-37 weeks may lead to shingles of infancy or early childhood
In up to 1/3 of infected people, VZV reactivates later

Question 15

What is the management for zoster

Answer 15

1. Famciclovir PO for 7 days OR valaciclovir PO for 7 days
2. Pain relief: paracetamol (mild) or oxycodone (m/s)
3. post-herpetic pain: paracetamol, capsaicin, tramadol