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Year 5 - Obstetrics and Gynaecology > Infection in pregnancy - CMV, VZV, rubella, toxoplasmosis, tuberculosis > Flashcards

Infection in pregnancy - CMV, VZV, rubella, toxoplasmosis, tuberculosis Flashcards

1
Q

What type of virus is Rubella virus? How is it spread?

A

Togavirus

Spread by droplet transmission

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2
Q

What is the trend in immunity to rubella in the UK?

A

Rubella is uncommon in the UK

But low antibody levels are found in those who should’ve had the MMR in 90s but refused due to media

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3
Q

Why do we not screen for rubella in pregnancy?

A

Prevalence is very low +

No effective intervention can be implemented during the pregnancy to reduce the harm to the fetus (this can only be donw outside of pregnancy with vaccination)

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4
Q

Why is the MMR vaccine contraindicated in pregnancy?

A

Could be teratogenic as it is a live vaccine but no cases of congental rubella syndrome from vaccination during pregnancy have been reported.

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5
Q

What precaution must be given after postpartum MMR vaccination?

A

Use contraception for 1 month

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6
Q

What are the clinical features of rubella in the mother?

A

Febrile rash

Asymptomatic in 20-50%

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7
Q

What are the complications of congenital rubella syndrome (CRS)?

A
  • Sensorineural hearing loss
  • Congenital cataracts
  • Blindness
  • Encephalitis
  • Endocrine problems
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8
Q

How does gestation at rubella infection affect pregnancy outcome?

A

Defects to fetus are less severe if infection occurs a t advanced gestations

Risks of congenital infection/defects:

  • <11 weeks = 100%
  • 12 weeks = 80%
  • 25 weeks = 25%
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9
Q

What is the management of rubella in pregnancy?

A

Assess CRS risk depending on gestation

  • Offer TOP if infection has occurred at <16 weeks
  • Reassure and inform about risks if infection is later in pregnancy
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10
Q

What is toxoplasma gondii?

A

Protozoa parasite found in cat faeces,soil or uncooked meat. Spread by ingestion.

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11
Q

How common is toxoplasmosis in general? How common is congenital toxoplasmosis?

A

May affect 1/3 people at some point in life

Congenital toxoplasmosis is rare affecting ~1 in 10,000

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12
Q

Why is there no screening for toxoplasmosis in pregnancy?

A
  1. Rare - only ~10 babies diagnosed per year in UK
  2. Lack of evidence that antenatal screening and treatment reduces vertical transmission or complications of toxoplasmosis.
  3. Benefits of programme are limited in other countries e.g. France
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13
Q

What advice should be given to women to prevent toxoplasmosis infection during pregnancy?

A
  • Avoid eating raw or rare meat
  • Avoid handling cats and cat litter
  • Wear gloves and wash hands when gardening or handling soil
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14
Q

What are the clinical features of toxoplasmosis?

A
  • Usually asymptomatic
  • Glandular fever-like illness
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15
Q

When does parasitaemia occur after toxoplasmosis infection?

A

Parasitaemia occurs within 3 weeks of infection so congenital infection is only a significant risk if mother acquires the infection during or immediately prior to pregnancy.

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16
Q

What are the complications of toxoplasmosis during pregnancy for the fetus?

A
  • Ventriculomegaly
  • Microcephaly
  • Chorioretinitis
  • Cerebral calcification

Usually asymptomatic at birth but develop sequelae several years later

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17
Q

At what gestation is toxoplasmosis infection likely to cause most harm to the fetus?

A

First trimester - severe fetal damage in 85% BUT only 10% transmitted

Third trimester - fetal damage in 10% BUT 85% transmitted

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18
Q

What tests are used to diagnose toxoplasmosis in pregnancy?

A

Maternal:

  • Sabin Feldman dye test
  • ELISAs are avaialble for IgM antibody - but IgM can persist for months/years so serial testing of rising titres is necessary

Congenital:

  • Amniocentesis and PCR of amniotic fluid
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19
Q

What is the management of toxoplasmosis?

A

Maternal infection:

Spiramycin 2-3g OD for 3 weeks

Fetal infection confirmed:

  • Antenatally:
    • Continue pregnancy with more aggressive antibiotic treatment - sulfadiazine + pyrimethamine
    • If toxoplasmosis is the cause of abnormalities on USS then offer TOP
  • Postnatally:
    • Treat baby for up to 1 year after delivery (if no TOP)
    • +/- prednisolone
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20
Q

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

A

DNA herpes virus

Transmitted by respiratory droplets and excreted in urine

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21
Q

What % of women at pregnancy are suspceptible to CMV? Is primary or secondary infection more likely to cause problems for the fetus?

A

60% are seropositive so 40% are susceptible to infection

Although you can get recurrent infection it is primary infection which has greater risk (40%) of causing congenital CMV.

22
Q

What are the clinical features of CMV in the fetus and neonate?

A

Fetus

  • FGR
  • microcephaly
  • intracranial calcification
  • ventriculomegaly
  • ascites
  • hydrops

Neonate

  • hearing loss
  • blindness
  • learning difficulties
  • anaemia
  • thrombocytopenia
  • hepatosplenomegaly and jaundice
  • purpural rash

Asymptomatic at birth but problems in later life

23
Q

What are the clinical features of CMV infection in the mother?

A

No symptoms

Mild non-specific flu-like symptoms

24
Q

How is CMV diagnosed in pregnancy?

A

Seropositivity - development of CMV antibodies in a seronegative woman with initially CMV IgM then IgG. Virology may keep a sample from early pregnancy to compare.

Amniocentesis + PCR - amniotic fluid tested for CMV by PCR (because the virus is excreted in fetal urine)

25
Q

What is the antenatal management of CMV infection in pregnancy?

A

Abnormalities seen on USS and CMV confirmed:

  • Discuss continuation of pregnancy with expectant management
  • OR offer TOP

If no abnromalities shown there is still 20% chance of neurological abnormality in the fetus.

Refer to fetal medicine specialist for regular fetal surveillance:

  • Fetal UUS every 2-4 weeks
  • +/- fetal MRI at 28-32 weeks
  • Audiology and ophthalmology follow up
26
Q

What is the postnatal management of CMV?

A

Start antiviral therapy for the baby within 4 weeks:

E.g. valganciclovir/ganciclovir - for 6 months

27
Q

How is VZV spread?

A

Droplet spread or direct personal contact

28
Q

How common is chickenpox infection in pregnancy?

A

3 in 1000 pregnancies affected; although contact with chickenpox in pregnancy is common, infection during pregnancy is rare.

29
Q

What are the clinical features of VZV infection in pregnancy?

A

Serious complications only likely in the non-immune population of pregnant women e.g.

  • pneumonia - affects 10% and is more severe at later gestations
  • hepatitis
  • encephalitis
  • death - mortality is x5 higher in pregnant women than in non-pregnant adults

Fetus:

  • fetal varicella syndrome
  • varicella infection of the newborn
30
Q

What counts as significant contact with chickenpox in pregnancy?

A
  • Being in the same room as someone for _>_15min
  • Face-to-face contact
31
Q

What is the infectivity period of chickenpox?

A

from 48 hours prior to appearance of the rash to ~5 days later when all vesicles have crusted over

32
Q

How is testing for immunity to chickenpox done?

A

Blood testing for VZV IgG - usually done in 24-48 hours and virology lab may have a sample stored from early pregnancy

33
Q

What is the management of the non-immune woman significantly exposed to chickenpox?

A
  1. Check for immunity to VZV - if unconfirmed…
  2. VZIG - effective when given up to 10 days after contact to prevent or attnuate the disease. Not effective once chikenpox has developed.
  3. Advise to notify doctor or midwife if rash develops
  4. Advise to avoid contact with other pregnant women and neonates- may be infectious despite exposure alone
34
Q

How long after contact with chickenpox is giving IVIG effective?

A

10 days

35
Q

What is the management of active chickenpox (i.e. with rash) in pregnancy?

A

Maternal infection outside of term:

  1. Aciclovir 800mg x5/day for 7 days - given within 24 hours of rash developing and 7-14 days after exposure
  2. Referall to fetal medicine specialist 5 weeks after infection or at 16-20 weeks - for discussion and diagnosis of complications
  3. Advise to avoid other pregnant women and neonates until 5 days affter rash onset (when all lesions have crusted over)

NB: if maternal infection occurs at within 4 weeks of term:

  • Elective delivery delayed until 5-7 days after onset of maternal rash - allows for passive transplacental transfer of antibodies
36
Q

Why are non-immune women who are significantly exposed to chickenpox advised to stay away from other pregnant women and neonates, even after receiving IVIG?

A

Women are considered infectious:

  • for 21 days after exposure if they don’t receive VZIg,
    • for 28 days after exposure if they do receive VZIg
37
Q

What is the fetal management in high risk of acquisition of VZV at birth?

A
  1. Neonatal opthalmic examination after birth
  2. Monitor infant for signs of infection for 28 days after onset of maternal infection
  3. VZIG - given if mother devleoped the VZV rash +/- 7 days of birth (i.e. antenatal or postpartum). Not effective if VZV has developed.
  4. Treat with aciclovir - if VZV develops
38
Q

True or false: spontaneous miscarriage is increased if chickenpox occurs in the first trimester.

A

False but fetal varicella syndrome may occur

39
Q

What are the features of fetal varicella syndrome?

A

FVS is characeterised by one or more of the following:

  • Skin scarring in a dermatomal distribution
  • Eye defects (microphthalmia, chorioretinitis, cataracts)
  • Hypoplasia of limbs
  • Neurological abnormalities (microcephaly, cortical atrophy, mental restriction, dysfunctional bowel and bladder sphincters)
40
Q

At what gestations is VZV likely to cause FVS?

A

3-28 weeks - less likely in the first trimester and no cases reported with infection after 28 weeks

41
Q

How do you prevent chickenpox infection in pregnancy?

A

Advise to avoid contact with anyone with chickenpox or shingles during pregnancy

Vaccination can be done if planning pregnancy but not given in pregnancy/post-natally.

42
Q

How does maternal TB affect the fetus or neonate?

A
  • Risk of vertical transmission is very low
  • Good outcomes with early diagnosis and treatment
  • Late diagnosis –> neonatal morbidity and mortality, prematurity, FGR and LBW in women with pulmonary TB disease
  • A mother with untreated pulmonary TB can infect her newborn baby
43
Q

In what situations is TB vaccination offered to neonates?

A

In the UK BCG is offered to all infants aged 0–12 months:

  1. in areas where the annual incidence of TB is 40/100,000 or greater,
  2. and to infants who have a parent or grandparent who was born in a country where the annual incidence of TB is 40/100,000 or greater
  3. or if close family has had TB
44
Q

What is the route of administration of the BCG vaccine?

A

Intradermally on arm

45
Q

What are the clinical features of tuberculosis?

A

fever, cough, weight loss, night sweats, and malaise

46
Q

What is the first line management of TB in a pregnant woman?

A

Refer to specialist

47
Q

What is the effect of pregnancy on TB infection?

A

Pregnancy does not definitively influence pathogenesis of TB or likelihood of progression from latent to active disease

BUT there is a significant increase in incidence of TB postpartum

48
Q

What is the management of latent TB during pregnancy?

A

If diagnosed prior to pregnancy and started on treatment: continue treatment with modifications for pregnancy

If diagnosed in pregnancy: weigh up risks of treatment with clinical circumstances like immunocompromise

Treatments include rifampin for 4 months OR isoniazid+ rifampin for 3 months OR isoniazid for 6/9 months

49
Q

How is TB diagnosed?

A

Clinical history

  • CXR - and if this is suggestive of TB…
  • 3 sputum specimens - for acid fast bacilli smear and culture
  • 1 sputum specimen for NAAT for M. tuberculosis

Also check for HIV.

50
Q

What is the management of active TB in pregnancy?

A

Active TB is associated with adverse maternal and fetal outcomes + untreated active TB represents a greater hazard to the mother and fetus than antituberculous therapy

The usual TB treatment is:

  • 2 antibiotics (isoniazid and rifampicin) for 6 months.
  • 2 additional antibiotics (pyrazinamide and ethambutol) for the first 2 months of the 6-month treatment period.

Most of these are thought to be safe in pregnancy, although not much data available for pyrazinamide.

If mother and infant have active and latent infection respectively then start both on treatment + no need to separate but wait until mother is no longer infectious.

51
Q

Is breastfeeding safe on antituberculous treatment?

A

Yes - no toxic effect on neonate

52
Q

What additionally should be prescribed when on antituberculous treatment?

A

Pyridoxine (vitamin B6) 25-50mg should be prescribed when taking isoniazid

Year 5 - Obstetrics and Gynaecology (87 decks)

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