11 Virus infection in pregnancy Flashcards

1
Q

why are viruses important in pregnancy

A

have to consider the potential effects the infection will have on the developing foetus and/or the new-born

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2
Q

what do all human herpesviruses have in common

A

all exhibit latency – remain infected for life, latent virus can reactivate and cause disease

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3
Q

how many herpesviruses are there

A

8

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4
Q

examples of herpesviruses

A
  1. Herpes simplex type 1
  2. Herpes simplex type 2
  3. Varicella-zoster virus
  4. Epstein-Barr virus
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5
Q

what is chickenpox called

A

varicella pneumonia

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6
Q

where does chickenpox infect

A

blood stream

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7
Q

what does chickenpox cause

A

rash over body

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8
Q

what does chickenpox infection do

A

During infection enters nerve terminals to nerve cell body – have the latent virus within the spinal cord and cranial nerves, can reactivate and cause rashes where only affects the area of skin that is supplied by the nerve the virus is reactivating
- causes shingles rash

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9
Q

what increases shingles likeliness

A

age

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10
Q

what is the effect on mother when pregnant with chickenpox

A

more likely to die

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11
Q

how can chickenpox in pregnancy be treated

A

aciclovir

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12
Q

what can chickenpox lead to

A

encephalitis = post infection, rare

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13
Q

what is Congenital varicella

A
  • as virus in the blood stream in chickenpox, viremia = affects foetus
  • can interfere with foetal development
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14
Q

what does Varicella embryopathy cause

A
  • Skin loss, scarring, usually unilateral, segmented
  • Impaired limb bud development
  • Many other, less specific features e.g. microcephaly, cataracts, IUGR
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15
Q

what is the problem neonatal varicella

A
  • baby is born before the mother has chance to make any antibodies that can cross placenta and infect baby
    = risk – neonatal chicken pox
  • rationale – exposure to virus in absence of passively acquired maternal antibody
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16
Q

how are maternal chickenpox situations managed

A

Try to stop the baby being born
Delivery >7 days after onset maternal rash – not sure if have any antibodies so do passive immunisation
VZIg to neonates born within 7 days of onset of maternal rash – or if post-natal maternal c-pox up to 30 days
Acyclovir given for 2 weeks-worth

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17
Q

what does VZIg do

A

does not prevent infection, but attenuates severity

18
Q

what is the risk of mother and child infected with chickenpox

A

Mother and baby are infection risk to staff, other patients

> infectious before you know it (have symptoms)

19
Q

what does the anti-VZV medication do

A

= reduce the chances that she will die of varicella pneumonia
= reduce the chances the virus is going to cross the placenta
- need to give the VZV within 10 days of exposure

20
Q

what are the problems with c-pox in pregnancy

A
  • C-pox in mother – risk to mother
  • C-pox in 1st 20 weeks – risk of fetal damage
  • C-pox in late pregnancy – risk of neonatal c-pox
  • Shingles in pregnancy – not common
21
Q

how many people die from neonatal herpes

A

of the 50% disseminated and/or neurological disease - 70% of these die

22
Q

what causes neonatal herpes

A
  • Primary
  • Recurrent
    Non-maternal source e.g. cold sore
23
Q

what is the difference for mothers that know they have genital herpes

A

risk of transmission very low (probably because of maternal antibody)

24
Q

if recurrent genital herpes during pregnancy what happens

A

c-section

25
Q

how can recurrence of genital herpes be reduced

A

aciclovir

26
Q

how is CMV infection spread to foetus

A
Crosses the placenta 
- primary infection
- recurring infection
- was infected as a child 
Secondary infection are much more common
27
Q

is there effect on the foetus when the infection occurs during pregnancy

A

defects are likely to be greater the earlier in pregnancy

28
Q

what % of maternal infections are transmitted to foetus

A

40%

29
Q

where is CMV present

A

oral and genital tract secretions, and urine

30
Q

how is CMV transmitted

A

sexual and via contact with contaminated objects – will survive on inaminate object

31
Q

how is CMV transmission reduced

A

Avoidance of contact with young kids implies very substantial behavioural modification

32
Q

why is CMV screening not advertised

A

(i) there is no sensible advice to give to seronegative women
(ii) recurrent CMV infection may also cause symptomatic congenital infection

33
Q

how is maternal CMV infection diagnosed

A
  • CMV IgM positive
  • CMV genome detection in blood, urine
  • Comparison with booking sample
34
Q

what are Hepatitis B virus: modes of transmission

A
  • Mother-to-baby (ie vertical)
  • Sexual
  • Blood exposure
35
Q

how is mother to baby transmission of hep B prevented

A

screen all babies

vaccinate if don’t have the antibodies needed

36
Q

what is the vertical transmission rate of hep C virus

A

3-5% (unless HIV co-infected)

37
Q

is it ok to breast feed with Hep C

A

yes

38
Q

what are the vertical HIV transmission routes

A
  • Antenatal – transplacental (unusual)
  • Perinatal – infected birth canal, exposure to maternal blood (most prevalent)
  • Postnatal – breast milk (HIV infected breast milk)
39
Q

is it ok to breast feed with HIV

A

no

40
Q

what is the overall rate of transmission for HIV to foetus

A

15-25

41
Q

how is HIV being prevented

A
Screen all antenates – anti-HIV
If anti-HIV positive
- Antiretroviral therapy during pregnancy
- Elective Caesarian section
- No breast-feeding
42
Q

what is the effect of parvovirus on pregnancy

A

increased spontaneous miscarriage
Foetal heart failure = accumulation of fluid – hydrops fetalis
No congenital developmental abnormalities