infections during pregnancy Flashcards
what class of the virus does varicella zoster virus belong too
herpesvirus 3
what type of virus is VZV?
- single stranded DNA virus
- double stranded DNA virus
- single stranded RNA virus
-double stranded RNA virus
double stranded DNA virus
what type of vaccine is varicella zoster
live attenuated
is it safe to vaccinate pregnant women who are not immune to VZV
no - can vaccinate when postpartum and safe to BF
Chelsie is struggling to conceive and is undergoing fertility tests. Her blood tests come back for VZV showing IgG negative, IgM negative.
what do these results mean?
If she decides to take the VZV vaccine how long would you recommend avoiding pregnancy for
non immune to VZV - offer vaccine pre pregnancy then need to avoid pregnancy for 4 weeks after completion of both doses
when is chickenpox considered contagious
2 days before the onset of the rash until the lesions have crusted over
in terms of pregnancy what is considered a significant exposure to chicken pox (VZV)
Significant contact is defined as contact in the same room for 15 minutes or more, face-to-face contact or contact in the setting of a large open ward
Jenny is currently 22 weeks pregnant and comes to her GP worried about the risk of chickenpox. She is a nurse teacher and one of the children yesterday came to nursery with a rash that the parents have since confirmed to be chickenpox. She doesn’t remember having chicken pox as a child.
What is the most appropriate next step in her management
A - prescribe oral acyclovir
B - ring maternity colleagues to arrange admission for IV acyclovir
C- serum IgG tests for VZV
d- reassure, not significant contact no need for further tests or treatment
C - test serum IgG levels to assess immunity
Jenny is currently 22 weeks pregnant and comes to her GP worried about the risk of chickenpox. She is a nurse teacher and one of the children yesterday came to nursery with a rash that the parents have since confirmed to be chickenpox. She doesn’t remember having chicken pox as a child.
Her serum IgG levels are negative. How should you manage Jenny?
Ring obstetric colleagues to arrange admission for IVIG - this needs to be given with 10 days of exposure
when is VZV immunoglobulin advisable
VZV Immunoglobulin is advised for all pregnant women who have had significant exposure to someone with VZV (chicken pox) regardless of their gestation, it should also be given up day 10 postnatal
what is the aim of VZV immunoglobulin
to reduce the risk of fetus developing congenital Varicella zoster, reduce maternal morbidity and mortality
what are the risks of VZV to mum
risk of developing pneumonia, encephalitis and hepatitis. VZV is associated with greater morbidity in adults
If a pregnant woman develops chicken pox rash within what time frame should acyclovir be considered as treatment
oral acyclovir advised to anyone > 20 weeks and consider if <20 weeks
oral acyclovir should only be given within 24 hours of the onset of the rash
is acyclovir licenced in pregnancy
no
if a pregnant woman develops severe VZV infection how should they be managed
IV acyclovir and admission
what is the mode of action of acyclovir
Aciclovir is a synthetic nucleoside analogue that inhibits viral DNA polymerase. Thus preventing the growing viral DNA chain.
Jane is 8 weeks pregnant and has been diagnosed with maternal VZV infection. She is worried about the risk of miscarriage, which of the following statements is true
A - the risk of spontaneous miscarriage does not appear to be increased if chickenpox occurs in the first trimester.
B- risk of spontaneous miscarriage is increased if chickenpox occurs in the first trimester
A - risk of spontaneous miscarriage does not appear to be increased if chickenpox occurs in the first trimester
what are the signs of fetal varicella syndrome
dermatomal skin scarring, eye defects, hypoplasia of the limbs and neurological complications
fetal varicella syndrome results from
A - initial infection of VZV
b- initial infection in utero of VZV
c- subsequent reactivation of herpes zoster in utero
c - subsequent reactivation of herpes zoster in utero
for women diagnosed with varicella infection during pregnancy what tests can they consider to diagnose the fetus with FVS
consider amniocentesis for VZV PCR but has good negative predictive value and lots of risks associated with it.
USS to look for signs of VZV in utero
VZV DNA per has a higher sensitivity than specificity
True or false
True
at what gestation in pregnancy is risk to the baby highest for development of varicella infection
last 4 weeks of pregnancy
what are the two oncogenes that HPV interferes with to cause cervical cancer
HPV is thought to induce cancer via onco-proteins. The primary onco-proteins are E6 and E7 which inactivate two tumor suppressor proteins, p53 (inactivated by E6) and pRb (inactivated by E7)
what family of viruses does rubella belong too
togavirus
how would congenital rubella infection present
sensoneural hearing loss
cardiac defects
cataracts
rubella is teratogenic and poor prognosis to the fetus
describe the virus of Rubella
single stranded RNA virus
what type of vaccine is the rubella vaccine
live attenuated
is it safe to vaccinate pregnant women with rubella vaccine
no - wait till postpartum fine to vaccinate when breast-feeding
A 30 year old patient is 36 weeks pregnant. She is known to be HIV positive and is having her viral load checked. What is the current BASHH advice regarding HIV positive mothers breastfeeding?
not safe to breastfeed
Congenital fetal varicella syndrome may occur if there is maternal varicella infection (chickenpox) during what gestation time period
A - during the 1st 20 weeks of gestation.
B - during last 20 weeks
a - during first 20 weeks of gestation
The risk of FVS to babies born to mothers who have chickenpox during the first 12 weeks is
0.4%
what is the risk of FVS to babies born to mothers who have chickenpox during 13-20 weeks of pregnancy
2%
what is the leading infective cause for congenital hearing loss
A - Rubella
B - toxoplasmosis
C- FVS
D- CMV
D - CMV
when is HSV transmission to a neonate the highest
A - in utero i.e. transplacentally
B - during vaginal delivery
B -during vaginal delivery
what are the three types of neonatal HSV infection
- localised skin infection
- CNS
- disseminated
what are the majority of neonatal HSV infections
CNS and disseminated (70%)
what is the mortality associated with neonatal disseminated HSV
30%
what is the mortality associated with neonatal CNS HSV
6%
at what gestation in pregnancy is risk of primary HSV infection considered to be the highest risk and why?
last 6 weeks due to risk of viral shedding and transmission to neonate during pregnancy. Hence if in last 6 weeks of pregnancy mum is diagnosed with primary HSV they should be started on oral acyclovir TDS and consented for c-section
Diana is 35 weeks pregnant and presented to her local GUM clinic with symptoms of primary HSV infection. Swabs diagnosed HSV type 1 and blood tests for HSV type 1 and 2 IgG are negative. How would you manage Diana?
this implies primary HSV and mum should be counselled for c-section delivery as this decreases risk of transmission to 0-3% and started on oral acyclovir 400mg TDS until delivery
what is the risk of HSV transmission to the neonate if primary infection in third trimester via NVD
41% risk via NVD - decreases to 0-3% if opts for c-section
what is the most common cause of congenital viral infection in the developed world?
CMV
what percentage of women with CMV during pregnancy will transmit it to their baby
40%
what type of virus is toxoplasmosis (DNA or RNA)
single stranded RNA virus
describe the morphology of toxoplasmosis genome
single stranded RNA virus, intracellular protozoon
what is the primary host of toxoplasmosis
cats - excreted in cats faeces and humans ingest it this way through uncooked meats
what are the classical sign of toxoplasmosis on MRI scan of the brain
ring enhancing lesions within CNS tissues
if a fetus is not infected with toxoplasmosis but mum is what would be the recommended treatment and for how long
spiramycin continued until term to try dn prevent fetal transmission
risk of fetal transmission increases towards term
listeria is a
gram negative rod intracellular protozoan
gram postive rod intraceullar protozoan
gram negative cocci intracellular protozoan
gram positive cocci intracellular protozoan
gram positive rod, intracellular protozoan
is listeria
anaerobic or aerobic
facultative anaerobic
where do you most commonly find listeria
moist soils environments
how is listeria transmitted to humans
eating soft cheeses and cold meats is how humans get infected with listeria
what effects can listeria have on a pregnancy
increases risk of chorioamnionitis, placental necrosis and granuloma formation
increased risks of miscarriage, stillbirth and meningitis
what family of viruses does the zika virus belong too
flavivirdae - flavivirus
is zika virus a single or double stranded DNA or RNA virus
single stranded RNA virus
how is zika virus transmitted to humans
ades mosquito
Mum is HIV +ve and on ART. VL at 36 weeks <50 what type of delivery can she have
any - can have NVD when VL < 50
Mum is HIV +ve and on ART. VL at 36 weeks >400 what type of delivery would be recommended
C/s as VL > 400
Mum’s VL is >400, despite being on ART but poor compliance. You recommend PLCS to reduce risk of vertical transmission. When would this be done if no other obstetric indications for c/s
planned for 38-39 weeks if c/s is due to risk of HIV vertical transmission.
whereas when it is obs risk not HIV usually elective c/s planned for 39 weeks instead
if mum is HIV positive and VL is between 50-400 what type of delivery would you recommend
mdt approach and taking into account patient wishes but grey area and due to risk of vertical transmission most likely would be a c/s
mum is diagnosed as HIV positive during first trimester - when do you aim to start ART by and when would you consider starting ART earlier
aim to start ART by 24/40 unless VL >100,000 or CD4 count < 200 in which case aim to start ART ASAP/ during first trimester
if VL <30,000 aim to start in second trimester
if VL 30,000-100,000 aim to start beginning of second trimester
do HIV positive pregnant women undergo extra obs testing
no - just routine antenatal consultant led care, no extra scans
what are the general rules in terms of EcV, invasive screening tests (amniocentesis,CVS) in a patient who is HIV positive
all can happen if VL <50
if VL higher then ideally defer until VL suppressed due to risk of vertical transmission
what are the categories for neonatal PEP
very low risk = 2 weeks zidovudine
low risk= 4 weeks zidovudine
high risk = 4 weeks combination PEP
what is the high risk PEP regime and when would you consider needing to start a neonate on high risk PEP
start ‘high risk pep’ category if mums VL is >50 at delivery or 36 weeks, mums VL is unknown, or suspected poor adherence to ART
combination therapy for 4 weeks:
1. zidovudine
2. lamivudine
3. nevirapine
should be started within 4 hours of birth
what is the very low risk PEP option for neonates and what categories must mum fulfil?
start within 4 hours of delivery, zidovudine mono therapy for 2 weeks.
Mum must have:-
1. VL at or after 36 weeks <50
2. established on ART >10 weeks
3. two VL > 4 weeks apart < 50
what is the low risk PEP option for neonates and what categories must mum fulfil?
start PEP within 4 hours
zidovudine (oral) mono therapy 4 weeks
criteria must be:
- mum VL at delivery < 50
- or baby born prematurely and last VL < 50
what specific ART would you need to prescribe high dose folic acid to pregnant women
dolutegravir - 5mg folic acid pre-conception and until 12 weeks
what is the pre-conception advice regarding vitamin d and folic acid
everyone should take folic acid starting minimum 1 month prior to conceiving and up until 12 weeks gestation 400 msgs (micrograms!)
vitamin d - 10 micrograms daily throughout pregnancy (avoid anything above 100mcgs)
high dose folic acid is 5mg (milligrams) only offer if:
- personal (either parents) or family history NTD
- previous pregnancy affected by NTD
- T2DM, sickle cell, thalassaemic inc thalassaemia trait
- BMI > 30
what situations do you carry high dose folic acid throughout pregnancy
sickle cell disease or thalassaemia inc thalassaemic trait.
