MI: Viral Infections in Pregnancy Pt.2

Question 1

List some factors affecting the transmission of HSV to the neonate.

Answer 1

• Type of maternal infection (primary infection carries greatest risk)
• Maternal antibody status
• Duration of rupture of membranes
• Integrity of mucocutaneous barriers (e.g. use of foetal scalp electrodes)
• Mode of delivery (vaginal delivery in a mother with genital HSV puts the baby at increased risk - C-section would be recommended)
• HSV infection at the latter end of pregnancy

Question 2

In which scenario will the neonate be at highest risk of acquiring HSV from the mother?

Answer 2

• Primary HSV infection in the 3^rd trimester (particularly within 6 weeks of delivery)
• C-section is recommended

Question 3

How is HSV infection in pregnacy managed?

Answer 3

• GUM referral
• Aciclovir
• Planned C-section if infection in the 3rd trimester

Question 4

How is recurrent HSV treated in pregancy?

Answer 4

• May not treat
• Consider daily suppressive aciclovir from 36 weeks
• Avoid PROM and invasive foetal monitoring

In recurrent infection, maternal antibody will offer some protection (but may not prevent transmission)

Question 5

Outline the manifestations of neonatal HSV disease.

Answer 5

• Skin, eyes, and mouth (SEM) - 45% of cases
• CNS (+/- SEM) - 30% of cases
• Disseminated infection (high mortality) - 25% of cases

If untreated, neonatal herpes has >80% mortality with severe neurological involvement

Question 6

How do SEM, CNS, and disseminated neonatal HSV infection present?

Answer 6

• SEM (first 2 weeks)- oral and skin vesicles, keratoconjunctivitis
• CNS (weeks 2-3) - seizures, lethargy, irritability, reduced feeding, fever, bulging fontanelle (requires CSF sample)
• Disseminated (week 1) - presents like sepsis, multiorgan involvement (liver, lungs, CNS, heart, GI, renal, bone marrow)

Question 7

Describe the clinical presentation of intrauterine HSV infection.

Answer 7

• Neurological - microcephaly, encephalomalacia, intracranial calcification
• Cutaneous - scarring, active lesions
• Ophthalmologic - microophthalmia, optic atrophy, chorioretinitis

Question 8

Outline the features of disseminated HSV infection.

Answer 8

• DIC
• Pneumonia
• Hepatitis
• CNS involvement

30% mortality rate even with treatment

Question 9

List some approaches to improving outcomes in neonatal HSV infection.

Answer 9

• Decrease time to diagnosis
• Early antiviral therapy
• Prompt collection of specimens

Question 10

Describe the treatment of neonatal HSV infection.

Answer 10

High-dose IV aciclovir (60 mg/kg/day) in three divided doses

• For 21 days minimum in disseminated disease (repeat LP and CSF PCR until PCR-negative)
• For 14 days minimum in SEM disease
• Monitor neutrophil count

Question 11

What type of virus is VZV? How is it transmitted?

Answer 11

• DNA herpes virus
• Transmitted via respiratory droplets (ISOLATE suspected cases)

Question 12

What are the risks to the mother of VZV infection during pregnancy?

Answer 12

• Pneumonia (10-20%)
• Encephalitis (5-10% mortality rate)

Question 13

What are the possible outcomes of intrauterine VZV infection?

Answer 13

• Congenital varicella syndrome
• Neonatal varicella
• Herpes zoster during infancy or early childhood

Question 14

List the main features of congenital varicella syndrome.

Answer 14

• Low birth weight
• Cutaneous scarring
• Limb hypoplasia
• Microcephaly
• Chorioretinitis and cataracts
• GORD

Question 15

At what stage in pregnancy is the risk of congenital varicella syndrome highest?

Answer 15

12-20 weeks (2% risk)

NOTE: shingles has no risk in pregnancy

Question 16

During which time period of maternal infection is a newborn vulnerable to acquiring neonatal varicella infection?

Answer 16

If maternal infection occurs within 7 days before to 7 days after delivery

NOTE: there is not enough time for maternal antibodies to develop and be transferred

Question 17

Describe the manifestations of neonatal varicella infection.

Answer 17

• Mild course
• Disseminated skin lesions
• Visceral infection
• Pneumonia

Question 18

How is antenatal varicella exposure managed?

Answer 18

• Check previous infection/vaccination status (if unsure, do VZV IgG serology)
• Give VZIG ASAP (effective for up to 10 days post-exposure)

Question 19

How is antenatal VZV infection managed?

Answer 19

Oral aciclovir (IV if severe)

Question 20

What type of virus is measles? How is it transmitted?

Answer 20

• RNA virus
• Transmitted via respiratory droplets (ISOLATE), conjuctiva