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MI: Viral Infections in Pregnancy Flashcards

1
Q

What are the three times at which viral infections can be transmitted from the mother to the baby?

A
  • In utero
  • Perinatally (from vaginal secretions and blood during labour)
  • Postnatally (from breast milk and other sources)
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2
Q

What are the potential viral causes of rashes during pregnancy?

A
  • VZV (chicken pox and shingles)
  • EBV
  • HSV
  • CMV
  • Parvovirus B19
  • Enterovirus
  • Measles
  • Rubella
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3
Q

What type of virus is rubella?

A
  • RNA virus
  • Togaviridae family
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4
Q

How is rubella transmitted?

A
  • Via respiratory droplets (therefore ISOLATE in suspected cases)
  • Virus replicates in lymphoid tissue of URT then spreads haematogenously
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5
Q

What are the symptoms of rubella infection?

A

20-50% subclinical

  • Prodrome (1-5 days pre rash) - coryza, sore throat, headache, low-grade fever
  • Fine macular rash - mildy pruritic, starts on face and spreads to trunk/limbs within hours
  • Lymphadenopathy - tender, postauricular/cervical/suboccipital
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6
Q

What is the classic triad of congenital rubella syndrome?

A
  • Sensorineural hearing loss
  • Congenital cardiac defects (mainly PDA)
  • Eyes - cataracts, retinopathy, microphthalmia
  • Other: mental retardation, meningoencephalitis, microcephaly, hepatosplenomegaly, thrombocytopaenic purpura
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7
Q

Describe the relationship between gestation at which rubella infection occurs and the risk of congenital abnormalities.

A
  • Highest risk from 0-12 weeks
  • Low risk from 13-20 weeks
  • Very low risk >20 weeks

If infected before 10 weeks, 90% incidence of foetal defects

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8
Q

Describe some tests that are used in the diagnosis of rubella.

A
  • Serology - IgG, IgM
  • Detection of virus (PCR) - blood, urine, tissues
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9
Q

What is the role of pre-natal diagnosis of rubella?

A

All cases of symptomatic rubella infection in the 1st trimester should be considered for termination of pregnancy without prenatal diagnosis

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10
Q

What type of vaccine is the MMR?

A

Live attenuated vaccine

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11
Q

What is the definition of congenital CMV infection?

A

Detection of CMV from bodily fluids (normally urine and saliva) or tissues within the first 3 weeks of life

NOTE: it is the MOST COMMON congenital viral infection

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12
Q

How is CMV transmitted?

A

Infectious bodily fluids: saliva, respiratory droplets, urine, blood, breastmilk

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13
Q

What are the main symptoms of CMV infection?

A

Largely asymptomatic

  • Maculopapular rash
  • Infectious mononucleosis-like illness
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14
Q

Describe the risk of transmission from primary vs non-primary infection

A
  • Primary infection - 30% transmit virus across placenta
  • Non-primary infection - 1% transmit virus across placenta

Non-primary infection far more common than primary infection due to high CMV seroprevalence rates

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15
Q

What is the term used to describe congenital changes that occur as a result of CMV infection? List some features.

A

Cytomegalic inclusion disease

  • CNS - microcephaly, ventriculomegaly, encephalitis, peri-ventricular calcifications
  • Eye - chorioretinitis
  • Ear - sensorineural deafness
  • Liver - hepatosplenomegaly, jaundice
  • Thrombocytopaenia

NOTE: late sequelae include hearing defects, mental retardation, and epilepsy

CMV associated with periventricular calcifications, whereas toxoplasmosis associated with diffuse intracranial calcifications

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16
Q

What is the risk of CMV non-primary compared to primary CMV infection to the foetus?

A

Lower risk of foetal abnormalities

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17
Q

What proportion of cases of congenital CMV infection are asymptomatic at birth?

A

90%

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18
Q

What is the most common neurodevelopment abnormality causes by congential CMV?

A

Sensorineural deafness

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19
Q

Outline some tests used in the diagnosis of CMV infection.

A
  • PCR of urine/saliva/amniotic fluid/tissue
  • Serology - IgG, IgM
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20
Q

How is suspected antenatal maternal CMV infection investigated?

A
  • If maternal CMV infection is suspected then check serology (compare booking to repeat sample)
  • If seroconversion suspected (i.e. infection during pregnancy) then refer to fetal medicine unit for USS +/- amniocentesis for CMV PCR
  • No treatment available
  • Neonates are investigated – urine and saliva CMV PCR within 1st 21 days.
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21
Q

Describe how foetal CMV infection is diagnosed

A

Amniotic fluid PCR at 21 weeks gestation

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22
Q

How is congenital CMV infection treated?

A
  • There is NO vaccine
  • Congenital CMV with significant organ disease
    • Valganciclovir or ganciclovir for 6 months
    • Audiology follow-up until age 6 years
    • Ophthalmology review
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23
Q

How are HSV 1 and 2 transmitted?
What are the incubation periods between oro-facial infection and genital infection?

A
  • Transmitted via direct contact with infected lesions
  • Oro-facial incubation - 2-12 days
  • Genital incubation - 4-7 days
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24
Q

What are the symptoms of HSV 1 and 2 infection?

A

Can be asymptomatic

  • Painful vesicular rash
  • Lymphadenopathy
  • Fever
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25
What is the difference between primary, non-primary, and recurrent HSV infection?
- **Primary infection** - first occurrence of gential HSV. No pre-existing HSV1 or HSV2 antibodies. - **Non-primary infection** - 1st episode of gential HSV but only has antibodies to the other HSV type - **Recurrent infection** - current HSV infection with pre-existing antibodies. Infection may previously have been asymptomatic or symptomatic.
26
How can HSV be transmitted to foetus and neonate?
Foetal infection - ascending infection in PROM Neonatal infection: - Direct contact with infected secretions during delivery - Kiss baby with oral herpes
27
List some factors affecting the transmission of HSV to the neonate.
* Type of maternal infection (**primary infection carries greatest risk**) * Maternal antibody status * Duration of rupture of membranes * Integrity of mucocutaneous barriers (e.g. use of foetal scalp electrodes) * Mode of delivery (vaginal delivery in a mother with genital HSV puts the baby at increased risk - C-section would be recommended) * HSV infection at the latter end of pregnancy
28
In which scenario will the neonate be at highest risk of acquiring HSV from the mother?
* **Primary** HSV infection in the 3rd trimester (particularly within 6 weeks of delivery) * C-section is recommended
29
How is HSV infection in pregnacy managed?
- GUM referral - Aciclovir - Planned C-section if infection in the 3rd trimester
30
How is recurrent HSV treated in pregancy?
- May not treat - Consider daily suppressive aciclovir from 36 weeks - Avoid PROM and invasive foetal monitoring ## Footnote In recurrent infection, maternal antibody will offer some protection (but may not prevent transmission)
31
Outline the manifestations of neonatal HSV disease.
* Skin, eyes, and mouth (SEM) - 45% of cases * CNS (+/- SEM) - 30% of cases * Disseminated infection (high mortality) - 25% of cases ## Footnote If untreated, neonatal herpes has >80% mortality with severe neurological involvement
32
How do SEM, CNS, and disseminated neonatal HSV infection present?
- SEM (first 2 weeks)- oral and skin vesicles, keratoconjunctivitis - CNS (weeks 2-3) - seizures, lethargy, irritability, reduced feeding, fever, bulging fontanelle (requires CSF sample) - Disseminated (week 1) - presents like sepsis, multiorgan involvement (liver, lungs, CNS, heart, GI, renal, bone marrow)
33
Describe the clinical presentation of intrauterine HSV infection.
* **Neurological** - microcephaly, encephalomalacia, intracranial calcification * **Cutaneous** - scarring, active lesions * **Ophthalmologic** - microophthalmia, optic atrophy, chorioretinitis
34
Outline the features of disseminated HSV infection.
* DIC * Pneumonia * Hepatitis * CNS involvement ## Footnote 30% mortality rate even with treatment
35
List some approaches to improving outcomes in neonatal HSV infection.
* Decrease time to diagnosis * Early antiviral therapy * Prompt collection of specimens
36
Describe the treatment of neonatal HSV infection.
High-dose IV aciclovir (60 mg/kg/day) in three divided doses * For 21 days minimum in disseminated disease (repeat LP and CSF PCR until PCR-negative) * For 14 days minimum in SEM disease * Monitor neutrophil count
37
What type of virus is VZV? How is it transmitted?
- DNA herpes virus - Transmitted via respiratory droplets (ISOLATE suspected cases)
38
What are the risks to the mother of VZV infection during pregnancy?
- Pneumonia (10-20%) - Encephalitis (5-10% mortality rate)
39
What are the possible outcomes of intrauterine VZV infection?
* Congenital varicella syndrome * Neonatal varicella * Herpes zoster during infancy or early childhood
40
List the main features of congenital varicella syndrome.
* Low birth weight * Cutaneous scarring * Limb hypoplasia * Microcephaly * Chorioretinitis and cataracts * GORD
41
At what stage in pregnancy is the risk of congenital varicella syndrome highest?
12-20 weeks (2% risk) ## Footnote NOTE: shingles has no risk in pregnancy
42
During which time period of maternal infection is a newborn vulnerable to acquiring neonatal varicella infection?
If maternal infection occurs within 7 days before to 7 days after delivery ## Footnote NOTE: there is not enough time for maternal antibodies to develop and be transferred
43
Describe the manifestations of neonatal varicella infection.
* Mild course * Disseminated skin lesions * Visceral infection * Pneumonia
44
How is antenatal varicella exposure managed?
- Check previous infection/vaccination status (if unsure, do VZV IgG serology) - Give VZIG ASAP (effective for up to **10 days** post-exposure)
45
How is antenatal VZV infection managed?
Oral aciclovir (IV if severe)
46
What type of virus is measles? How is it transmitted?
- RNA virus - Transmitted via respiratory droplets (ISOLATE), conjuctiva
47
Describe the symptoms of measles.
* Prodrome (2-4 days): fever, malaise, coryza, * Conjunctivitis * Kopolik spots * Maculopapular rash starting at hairline and spreading to trunk/limbs within 3 days
48
List some maternal complications of measles infection.
* Secondary bacterial infection (otitis media, pneumonia, bronchitis) * Encephalitis * Subacute sclerosing panencephalitis
49
What are the risks of measles in pregnancy?
* Foetal loss (miscarriage, intrauterine death) * Preterm delivery * Increased maternal morbidity IMPORTANT: **NO congenital abnormalities** to the foetus
50
How should pregnant women who have been in contact with suspected/confirmed measles be treated?
Measles immunoglobulin attenuates the illness if given within 6 days of exposure
51
What type of virus is parvovirus B19?
* DNA virus * Parvoviridae family
52
Describe the clinical presentation of parvovirus B19 infection.
Mostly **asymptomatic** * Erythema infectiosum (fifth disease, slapped cheeck syndrome) * Transient aplastic crisis * Polyarthropathy
53
Outline the pathophysiology of parvovirus B19 infection.
* Tropism for rapidly-dividing erythrocyte precursors * Causes suppression of erythrogenesis * NO reticulocytes are available to replace egeing or damaged arythrocytes as they are cleared by the reticuloendothelial system
54
At what stage in pregnancy is parvovirus B19 infection most concerning?
**<20 weeks gestation** - 33% risk of tranmission to foetus - 9% infection risk - 50% of foetal infections result in intrauterine death ## Footnote Infection >20 weeks has no documented risks
55
What is the main complication to the foetus from parvovirus B19 infection?
- Viral destruction of erthrocyte precursors causes severe anaemia - This leads to high-output heart failure and hydrops fetalis
56
How is parvovirus B19 infection <20 weeks managed?
- **Referral to fetal medicine** for monitoring - May require **intrauterine blood transfusion** - Some will resolve spontaenously - If the foetus survives the hydropic state, they have a good prognosis
57
Describe how maternal parvovirus B19 infection can be diagnosed.
* Viral detection (PCR) * Serology
58
Name some human pathogenic enteroviruses? How can they be transmitted?
Transmitted via respiratory droplets +/- faecal
59
What are the symptoms of enterovirus infection?
- Hand, foot, mouth disease - Rash - Encephalitis - Myocarditis
60
Which enterovirus presents the biggest risk to the neonate?
**Coxsakie virus** - Perinatal infection can occur in the last week of pregnancy - Neonates are at risk of myocarditis, fulminant hepatitis, bleeding, and multi-organ failure
61
Outline the symptoms of Zika virus.
* 80% asymptomatic * May cause fever, rash, myalgia and arthralgia
62
What are some consequences of Zika virus infection in pregnancy.
* Miscarriage * Stillbirth * Congenital Zika syndrome * Severe microcephaly * Decreased brain tissue * Seizures * Retinopathy/deafness * Talipes * Hypertonia
63
What advice can be given to pregnant women who are concerned about Zika virus?
* Bite avoidance * Avoid travelling to Zika endemic countries if pregnant * Avoid conception 2-6 months after travel to Zika endemic country (6 months for men, 2 months for women) * Test only if symptomatic or abnormalities seen on USS
64
What questions to ask pregnant women presenting with rashes in history?
65
What is the general investigations to conduct in pregnant women with rashes?
66
What is subacute sclerosing panencephalitis?
* Fatal progressive degenerative disease * Tends to occur 7-10 years after measles infection * Present with delays motor skills and behavioural problems

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