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Lecture week 4 > Infections in Pregnancy > Flashcards

Infections in Pregnancy Flashcards

1
Q

Varicella Zoster Virus (chickenpox)

  • What risks does the infection pose on a pregnant woman?
A

5 times greater risk of viral pneumonitis (may be difficult to cope with or even fatal)

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2
Q

Vricella Zoster Virus (chickenpox)/ Shingles

  • What’s the management if a pregnant woman is exposed to chickenpox?
A

Management: (VZV and shingles exposure)

  • Check maternal blood -> was she previously exposed
  • If not immune -> give Varicella-Zoster immunoglobulin (VzIg) ASAP following exposure (ideally within 4 days, up to 10 days)
  • Give high dose of acyclovir (if a pregnant woman presents with rash after exposure)

*acyclovir for all adults with VZV

*immunoglobulin makes the illness less severe (but does not prevent it)

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3
Q

Varicella-Zoster infection – foetal effects

  • What’s the foetal effect name?
  • When does it occur and what’s the risk of it occurring (times of exposure during gestation)
A

Congenital Varicella Zoster Syndrome:

  • If maternal chickenpox in first 20 weeks of pregnancy (risk <1%)
  • Some (small number of cases) occurring between 20-28th week
  • None after 28th week
  • just before or just after the delivery -> possibly severe neonatal chickenpox (sometimes severe) -> give immunoglobulin to a baby
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4
Q

Congenital Varicella-Zoster Syndrome

Features (what does it cause ?)

A

Congenital Varicella Zoster Syndrome:

  • skin scarring
  • eye defects (microphthalmia)
  • limb hypoplasia
  • microcephaly
  • learning disabilities
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5
Q

Neonatal chickenpox

  • what can be its manifestation (in mum)?
  • how does it occur/ pathophysiology?
  • management
A

Maternal rash up to 4 days before and 2 days after delivery -> 20% risk of neonatal chickenpox

*if infection earlier - mum will develop antibodies and they will pass the placenta and protect a baby

Pathophysiology: Infection with VZV but no maternal antibodies (so baby gets a big dose of a virus bit no antibodies pass across the placenta to provide protection for a baby)

Management: VZV immunoglobulin if high risk of a neonatal death

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6
Q

Parvovirus B19

  • other name
  • why such a name? (symptom)
A

‘Slapped cheek syndrome’

  • The rose-red rash -> cheeks appear bright red
  • The rash may spread to the rest of the body but rarely involves the palms and soles

*may also occur in children

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7
Q

Parvovirus B19

  • how is it spread
  • how long is the person infectious before the appearance of a rash
  • is a person infectious once the rash appears

-

A
  • spread by the respiratory route
  • a person is infectious 3 to 5 days before the appearance of the rash
  • Children are no longer infectious once the rash appears and there is no specific treatment.

The child need not be excluded from school as they are no longer infectious by the time the rash occurs.

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8
Q

Parvovirus B19 infection

  • symptoms in a pregnant woman
  • diagnosis
A

Symptoms: mild flu-like illness, often asymptomatic, sometimes rash

Diagnosis: detection of virus in blood (PCR during a febrile illness, Iga M when rash develops)

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9
Q

Parvovirus B19

  • when the exposure is the most dangerous for the foetus
  • when the infection is the most infectious?
A
  • virus can affect an unborn baby in the first 20 weeks of pregnancy
  • If a woman is exposed early in pregnancy (before 20 weeks) -> seek advice from a antenatal care specialist

The most infectious during a febrile illness (not infectious during rash) -> lots of exposures therefore are missed

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10
Q
  • Effects of Parvovirus B19 infections on the foetus
  • why do they occur? (pathophysiology)
A
  • maternal infection in first 30 weeks -> foetal loss

Pathophysiology:

  • Parvovirus B19 infects RBCs -> Hydrops foetalis (anaemia, heart failure, death) *usually few weeks after maternal infection)
  • as a heart needs to pump a much greater volume of blood to provide tissue perfusion due to severe anaemia -> increased demand on cardiac output -> heart failure

Higher risk of hydrops foetalis if mum infected before 20 weeks (as short life of foetal RBCs produced in foetal liver at that stage)

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11
Q

Management of Parvovirus B19 infection if a foetus is affected

A

Early diagnosis of anaemia by Doppler USS -> Intrauterine blood transfusion

*USS will measure blood velocity/speed in the foetal middle cerebral artery

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12
Q

What do we do if a pregnant woman was exposed to Parvovirus B19?

A
  • test mum for immunity (IgM, IgG) -> to check if they are immune (if yes, no need to worry as would not acquire infection second time around)
  • if susceptible -> repeat tests 4 weeks after exposure (to detect asymptomatic infections)
  • if infection detected -> weekly USS scans up t 30th weeks and then every 3 weeks
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13
Q

Cytomegalovirus (CMV)

  • is it common?
  • is it symptomatic?
  • how a primary maternal CMV infection is diagnosed?
A
  • 50% of the population has been already exposed ->however a disease is caused only in immunocompromised (HIV, organ transplant)
  • mostly asymptomatic (therefore mum would not know she acquired the infection)
  • diagnosis: IgG and IgM serology, more specific antibodies tests
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14
Q

CMV effects on the foetus

A

Congenital CMV infection features include:

  • growth retardation
  • pinpoint petechial ‘blueberry muffin’ skin lesions,
  • microcephaly
  • sensorineural deafness
  • encephalitiis (seizures)
  • hepatosplenomegal
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15
Q

CMV

  • how is it detected in the foetus
  • how is it detected in a baby
A
  • Foetus: amniotic fluid tests after 22nd week of gestation -> as lots of CMV excreted from foetal kidneys into the amniotic fluid a that stage
  • Baby: urine or saliva from the baby -> look for a virus by using PCR
  • *(need to be done in first 3 weeks of life - otherwise does not indicate that it was acquired in utero)
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16
Q

CMV in neonates

  • how do we manage
  • can we treat in utero
A

Neonate - symptomatic:

IV Ganciclovir

(if diagnosed 1 month after birth)

In utero: no treatment as harmful

17
Q

Infections and maternal health

  • What infections Infections that may cause severe life-threatening disease in pregnant women
  • why?
A
  • chickenpox -> pneumonia
  • influenza -> pneumonia
  • hepatitis E -> liver failure

*this is not due to immunosuppression but as consequence of anatomical changes occurring in pregnancy (e.g. abdomen pushes on thorax - unable to cough effectively etc)

18
Q

What’s the difference between:

  • transplacental/congenital infection
  • intrapartum/perinatal infections
A
  • Transplacental / congenital infections = some infections invading the mum’s blood stream -> cross the placenta and therefore infect the foetus
  • Intrapartum/ perinatal infections -> Infections may be acquired by a newborn during delivery (e.g. microorganisms in the birth canal)
19
Q

What potentially happens to the foetus, when infection occurs at:

  • first few weeks of gestation
  • after 6th week of gestation
A

First few weeks of gestation

Embryonic death and reabsorption (usually before woman realises she is pregnant)

After 6th week

Overwhelming foetal infection and death:

  • spontaneous abortion/ miscarriage in weeks 5- 14
  • intrauterine death or stillbirth in week 25
20
Q

What potentially happens to the foetus, when infection occurs at:

  • live birth of a baby
A

Live birth of a baby

Developmental anomalies e.g. Congenital Rubella Syndrome (heart and eyes defects - cataracts)

Congenital disease

  • jaundice
  • pneumonia

May be present at birth or soon after birth

21
Q

What is seen on the brain scans of a baby suffering from a congenital CMV infection?

A

Periventricular calcification

22
Q

Congenital Rubella Syndrome

  • features
A
23
Q

What pregnant women are screened for in the UK (in terms of infections)?

What’s its aim?

A
  • In the UK, screening on pregnant women: HIV, HiB and syphilis
  • Aim: to identify people at risk -> to investigate them further -> to act on or to take preventative action on people at risk who do not have disease manifestation yet
24
Q

Are pregnant women in the UK screened for: CMV and toxoplasmosis?

A

no screening for CMV or toxoplasmosis in the UK, as there are no appropriate interventions that would improve clinical outcomes

25
Q

Herpes simplex infection

  • Transmission (in terms of a baby)
  • Clinical features of an infected pregnant woman
A

Transmission: 85% during delivery (infected birth canal), 5% in utero, 10% acquired post natal period (e.g. via close contact with HSV infected cold sores, skin lesions)

Clinical features: same in pregnant women as in non-pregnant women (no more severe in pregnant); majority are asymptotic; if symptoms: skin lesions on genitals

26
Q

What are three categories of neonatal infection with Herpes Simplex?

A

Categories of HSV in neonatal infection:

  1. Disease disseminated in many organs (among this CNS is often involved)
  2. CNS - brain is damage but no other organs involved
  3. Disease is limited to the skin
27
Q

Diagnosis and treatment of Herpes Virus infection in a neonate

A

Treatment: high dose Acyclovir

Diagnosis: swabs and PCR; vesicular fluid, CSF, blood - we test all these in order to maximise a chance of virus detection

28
Q

Prevention of HSV transmission from a mum (if she is infected) to a baby + when do we do it?

A

Prevention:

  • prevent exposure to the virus during birth = use CS (if mum has vesicular lesions in genital tract)
  • Acyclovir given to mum
  • CS not recommended if lesions are visible >6weeks before delivery - as HSV transmission would be unlikely
29
Q

What is the reason behind the fact that:

  • primary Herpes simplex infection would be transmitted from a mum to a baby (through birth canal) at risk 33-50%
  • but recurrent only <5%
A

Reason:

  1. Higher levels of virus in genital tract and length of the virus is longer during primary infection compared with recurrent
  2. Mum passes IgG to protect baby from infection; in primary infection it takes 8 weeks to develop antibodies (so in recent/primary baby may not have maternal antibody to protect it from HSV) ; when in recurrent infection antibody will be already produced
30
Q

What vaccinations can be offered to pregnant women and when?

A
  • Influenza vaccination
  • Pertussis vaccination

* a pregnant woman is offered both - influenza at any time during pregnancy (during the flu season) and from 16-32 weeks gestations for pertussis.

31
Q
A

Lecture week 4 (18 decks)

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