Herpes Simplex Virus Flashcards
Define
DNA virus
Two types: 1 (oral>genital) or 2 (genital>oral)
Spread to neonate – through direct contact with infected maternal secretions (transplacental possible), risk of neonatal transmission at vaginal delivery is 41% with primary lesion or 2% with recurrent lesions
Risk factors
Aetiology: physical/sexual contact; vertical
Risk factors: unprotected sex, immunosuppression, other STI
Factors influencing transmission:
- Type of maternal infection (primary or recurrent)
- Primary episode- 57% risk of neonatal infection
- First episode non-primary- 25% risk
- Recurrent episode(s)- 2% risk
Presence of transplacental maternal neutralising antibodies
Duration of rupture of membranes before delivery
Use of foetal scalp electrodes/ integrity of mucocutaneous barriers
Mode of delivery
- Vaginal- increased risk
- C-section- PREFERRED
Epidemiology: 2% of pregnant women
Signs and Symptoms
Maternal:
- Asymptomatic
- Oral herpes
- Genital herpes (dysuria, frequency)
- Disseminated herpes (encephalitis, hepatitis, disseminated skin lesions)
IU HSV infection
- Microcephaly
- Encephalomalacia
- Hydranencephaly and/or intracranial calcification
- Scarring, active lesions, hypo- and hyperpigmentation
- Microphthalmia, retinal dysplasia, optic atrophy and/or chorioretinitis
Neonatal: 1 per 60,000 live births -> SEM (skin, eyes, mouth) , CNS ± SEM or disseminated infection:
Skin, Eye and Mouth (SEM) disease - 45%
- Blistering vesicular rash
- Chorioretinitis
CNS disease ± SEM 30%——— Mortality 6% (high morbidity)
- Seizures
- Lethargy
- Presents 10d-4w postpartum
- Irritability
- Poor feeding
- Temperature instability
- Bulging fontanelle
Disseminated infection involving multiple organs 25%——— High mortality (30%)
- Encephalitis (60-70%)
- CNS (60-75%)
- Hepatitis
- Pneumonitis
- No skin lesions (>20%)
- DOC
Investigations
Clinical diagnosis ± STI screen
PCR virus
Management
ACUTE INFECTION Aciclovir (400mg, TDS):
- Maternal:
- <26w primary infection -> oral aciclovir; 36 weeks until delivery
- >26w primary infection -> oral aciclovir until delivery
Neonate:
- IV aciclovir to child (14d if SEM disease -> 21d if CNS or disseminated)
+ monitor neutrophil count
DELIVERY (primary infection):
1st episode ≥6w prior to EDD -> SVD
1st episode ≤6w prior to EDD -> C-section
Perform HSV (type-specific) antibody testing
If the woman chooses vaginal delivery:
- Rupture of membranes and invasive procedures should be avoided
- IV aciclovir given intrapartum to the mother (and the neonate)
- Avoid invasive procedures in labour (e.g. forceps delivery) -> increase risk of neonatal HSV
DELIVERY (recurrent episodes) -> SVD (only a 2% risk of transmission if recurrent; due to maternal IgG)
- Daily suppressive aciclovir 400mg TDS from 36 weeks’ gestation
- Avoid invasive procedures during labour if genital lesions (i.e. foetal scalp electrodes)
Complications
Herpes is particularly dangerous when acquired around the time of delivery, with serious neonatal consequences
Premature rupture of membranes and preterm delivery
Prognosis -> neonatal mortality from 2% (local disease) to 50% (disseminated disease)
- Improved outcomes if early diagnosis and initiation of antiviral therapy