HSV Flashcards
What does the different stages of HSV infection mean?
primary,
recurrence,
non primary first episode
Primary First gential lesions and no pre-existing HSV 1 or 2 IgG
Non primary first episode – HSV gential lesions that are a different type fo antibodies pt has (Usually swab + HSV 2 with existing HSV1 Abs)
Recurrent – Genital swabs same HSV as pre-existing ABS (not all first infection has sx so a pt maybe unaware the infection is new)
What test to confirm herpes?
PCR +/- culture on genital swab and HSV type specific serology 7 (PCR more sensitive)
Screen for other STIs
Do we treat primary herpes infections?
Treat primary infections with antivirals – to limit number and length of time with lesions + viral shedding + reduce complicated infection 7-10/7
What is the fetal transmission rate
Primary infection Seroconversion before 30-34 weeks – risk same as for recurrent herpes Otherwise risk 25-50%
Non Primary first episode 25-30%
Recurrence If in the genital tract at the time of delivery overall risk 1-3%
HSV1 risk 15% HSV 2 risk <0.01%
Pregnancy implications
PTL IUGR Spontaneous abortion are reported but rare
When does the baby catch HSV
85% are acquired perinatally
Intrauterine infections <5%
25% of cases a possible source of
postnatal infection was identified, usually a close relative of the mother
What intrapartum interventions / or conditons affect HSV transmission
FSE increases the risk of transmission
LSCS reduces the risk of transmission
Rype of maternal infection (primary or recurrent),
The presence of transplacental maternal neutralising antibodies,
the duration of rupture of membranes
How to manage :
Primary HSV in labour
Primary HSV in T1 or T2
Primary HSV in T3
in labour first presentation - recommend LSCS 25-50% transmission - the benefit of caesarean section
reduces if the membranes have been ruptured for greater than 4 hours but still useful
In T1 or 2 - manage as recurrent
T3 - ( within 6 weeks of delivery) suppressive tx and LSCS 25-50% transmission
How to manage recurrent HSV in antenatal
Serial genital cultures are not recommended
Consider suppressive antiviral therapy from 36 weeks – acyclovir 400 mg tds
careful speculum when presents in labour
intrapartum management Recurrent HSV in pregnancy
Lesions
No lesions
if no lesions: then for vaginal birth
If lesions as the actual risk of transmission is low 0-3% (netherlands study says no increased risk in a vaginal birth) mothers decision
It has been reported that invasive procedures (fetal blood sampling, application of fetal scalp electrodes, artificial rupture of membranes and/or instrumental deliveries) increase the risk of neonatal HSV infection.
However, given the small background risk (0–3%) of transmission in this group, the increased risk associated with invasive procedures is unlikely to be clinically significant so they may be used if required.
What are the fetal complications (3 categories)
● disease localised to skin, eye and/or mouth - 30% of neonatal herpes infections. With tx neurological and/or ocular morbidity is less than 2%.
● local central nervous system (CNS) disease (encephalitis alone) 70% (60% without skin, eye and/or mouth infection) often present late (D10 - 4 weeks). With tx mortality 6% and neurological
morbidity (which may be lifelong) is 70%
● disseminated infection with multiple organ - mortality is around 30% and 17% have long-term neurological sequelae
- more common with primary infection and PTB
What is the rate HSV 1 vs 2
Approximately 50% of neonatal herpes is due to HSV-1 and 50% due to HSV
Consequence of HSV for the mother
Disseminated herpes, which may present with encephalitis, hepatitis, disseminated skin lesions or a
combination of these conditions, is rare in adults. However, it has been more commonly reported in
pregnancy, particularly in the immunocompromised. The maternal mortality associated with this
condition is high.
All immunocompromised women, such as those infected with the HIV virus, are at increased risk of more severe and frequent symptomatic recurrent episodes of genital herpes during pregnancy and of asymptomatic shedding of HSV at term
As co-infection with HSV and HIV
results in an increased replication of both viruses, HSV may increase HIV transmission
no increase T1 mc, no congential abnormalities
Aciclovir in pregnancy
The use of aciclovir is
associated with a reduction in the duration and severity of symptoms and a decrease in the duration of viral shedding. Aciclovir is not licensed for use
in pregnancy but is considered safe and has not been associated with an increased incidence of birth defects. Transient neonatal neutropenia has
been reported but no clinically significant adverse maternal or neonatal effects have been reported. Aciclovir is well tolerated in pregnancy.
How to manage PPROM HSV primary infection
Recurrent infection
o guidance - ob decision
For for urgent LSCS - benefit reduced transmission
If there is initial conservative management, the mother should be recommended to receive intravenous aciclovir 5 mg/kg every 8 hours.
Prophylactic corticosteroids
If delivery is indicated within 6 weeks of the primary infection, delivery by caesarean section may
still offer some benefit despite the prolonged rupture of membranes.
Recurrent: very small risk
In the case of PPROM before 34 weeks there is evidence to suggest that expectant management is appropriate, including oral aciclovir 400 mg
three times daily for the mother. After this gestation, manage as standard PPROM + not really affected by HSV
