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Flashcards in Congenital and perinatal infections Deck (73):
1

Describe the different timings of congenital and perinatal infections?

Prenatal: acquired/carried by mother and transmitted to developing foetua

Perinatal: infection transmitted around time of delivery

Postnatal/Postpartum: infection acquired after delivery (from family, health care workers, community, etc.)

2

Describe the different modes of infection for congenital and perinatal infections?

Vertical transmission: mother to foetus (e.g. transplacental)/baby (e.g. breast milk)

Horizontal transmission: one person/baby to another

Ascending: vaginal organisms producing foetal infection

3

Describe varicella zoster virus?

Herpesviridae family

Large

Icosahedral

dsDNA

Enveloped

4

Where does the latent infection of VZV reside?

Dorsal root ganglia

5

What does VZV cause?

Chickenpox and herpes zoster (shingles, after reactivation)

6

What is the incubation period for chickenpox?

10-21 days (median 14)

7

How is chickenpox transmitted/

Respiratory

Direct contact 

8

Describe the presentation and duration of chickenpox?

Fever
Lethargy
Pruritic vesicular rash

2-6 days

9

Describe the complications of chickenpox?

Secondary bacetrial infection: commonly strep pyogenes or staph aureus (enter via skin lesions)

Pneumonitis: more common in adults

Acute cerebellar ataxia

10

In which population is chickenpox most severe?

Pregnant adults

 

 

11

Describe the consequeces of maternal varicella for the mother?

Respiratory symptoms days 2-5

Death most common in third trimester (2% mortality)

12

Describe the consequences of congenital varicella syndrome?

Limb hypoplasia

Cicatrical scarring (dermatomal)

Microcephaly

Cataracts

Mental retardation

GIT and genitourinary abnormalities 

13

Describe how the risk of congenital varicella syndrome varies with gestation?

2-12 weeks: 0.55%

12-28 weeks: 1.4%

Latest gestation: 28 weeks

 

14

When does perinatal varicella occur?

When mother develops primary maternal varicella -7 to +2 days from delivery

15

Describe the rate of transmission of primary maternal varicella to the neonate?

17-30% transmission

16

Describe the mortality associated with perinatal varicella?

25-30%

Disseminated infection

17

What is prophylactic VZIG used for?

Prophylactic varicella zoster immunoglobulin

Given post-exposure (<96 hours) to: suscpetible pregnant women, infants whose mothers develop varicella < 7 days prior to delivery and in first month of life, immunocompromised and premature babies (< 28 weeks)

 

18

Describe the treatment of varicella?

Acyclovir

Oral if <24 hours of rash and no systemic symptoms

IV if pneumonitis, neuro symtpoms, organ involvement, haemorrhagic rash 

19

Describe the varicella vaccine?

Live attenuated virus

Given at 18 months (MMRV) or to non-immune adults in 'high-risk' occupations

100% protection against severe disease, 70% protection against any disease 

20

Describe cytomegalovirus?

Herpesviridae family 

Icosahedral

dsDNA

Lipid envelope

Produces multinucleate giant cells 

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21

Where does the latent infection of CMV reside?

WBCs

22

Desribe the epidemiology of CMV?

Primary infection

Recurrent infection: reactivation or re-infection (with different strain)

23

Describe the transmission of CMV?

Saliva
Urine
Blood
Semen
Breast milk
Cervical secretions
Transplacental
Transplant tissue

 

Of those who are seropositive, 10% will be shedding virus at any one time
90% of immunosuppressed patients shedding virus  

24

Describe the seroepidemiology of CMV?

World-wide, no seasonal predilection

Dependent on: SES, cultural background, geographic location, exposure to children, age

Increased rates during childhood, adolescence and child-bearing years

Most exposure in childhood in developing countries, lots in adults in developed countries 

25

Describe how and why CMV may be acquired postpartum?

Low birth weight infants have little maternal Ab

Transfusion acquired
Horizontal spread from shedders
Breast milk

26

Describe the presentation of postpartum CMV in a neonate?

Non specific, sepsis-like syndrome

Hepatomegaly
Respiratory distress
Atypical lymphocytosis

27

What is the most common congenital viral infection?

Congenital CMV

0.3-2% all live births 

28

Which form of CMV is riskiest for the baby?

Primary infection in mother

10% symptomatic
Mortality 10-30%
Long-term sequelae

29

Describe the prevalence and rates of fetal infection for both primary and reactivation CMV in the mother?

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30

Describe the prevalence and risk of long-term sequelae for asymptomatic and symptomatic neonatal CMV?

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31

Describe the laboratory tests for CMV?

IgG: appears and remains for life

IgM positive: acute infection

IgG avidity: Ab binds Ag weakly in first 3-4 months of infection

NA detection

32

Describe the interpretation of laboratory results for CMV testing?

Primary infection: IgG and IgM often positive
IgM detectable for months 

Reactivation: IgM may be detectable 

So, can be hard to distinguish

33

How can foetal infection with CMV be confirmed?

Amnitoic fluid > PCR

Have to get timing right (allow enough time mother's primary infection and baby neginning to shed virus into amnioitic fluid)

34

Describe the actions that occur if a baby infected with CMV is normal at birth?

Serial audiometry and visual assessment

Psychomotor assessment

Watch for pneumonitis

35

Describe the actions taken if a baby with CMV infection is symptomatic at birth?

Confirm diagnosis: urine in first 2 weeks

Cranial US and other imaging
Developmental paediatrician
Physio
Sppech therapist
OT
Audiometry and visual assessment

36

Describe the treatment for CMV?

Ganciclovir

Omly administered to symptomatic neonates
IV for 6 weeks

Consider oral valganciclovir for 6 months 

37

Describe rubella virus?

Togavirus family 

ssRNA

Enveloped

38

When is the peak for rubella infection?

Winter-Spring

39

How many patients with rubella infection are symptomatic?

50-75%

40

What is the incubation period for rubella virus?

14-21 days

41

How is rubella transmitted?

Nasopharyngeal secretions

Infectious from -7 to +14 days of symptoms 

42

Describe the clinical presentation of rubella?

Low-grade fever

Lymphadenopathy (nodes on back of neck for 2-3 weeks)

Exanthem

Polyarthralgia/arthritis

43

Describe how the risk of damage in congenital varicella syndrome varies with gestation?

< 4 weeks: 85%

4-8 weeks: 20%

9-12 weeks: 5%

> 16 weeks: rare

 

>12 weeks: retinopathy and deafness only

44

Describe the consequences of congenital rubella syndrome?

1/3: normal life, live with parents, institutionalised

Opthalmological: cataracts, glaucoma, retinopathy

Cardiac: patent ductus arteriosus, PA stenosis

Auditory: sensorineural deafness

Neurological: meningoencephalitis, behavioural

45

Describe the investigation of rubella?

Serological confirmation: IgG seroconversion or rising titre, IgM

Foetal diagnostic testing: amnitoic fluid

46

Describe the preventin of rubella?

Live attenuated vaccine (MMR)

Seronegative women vaccinated postpartum (not during pregnancy)

47

Describe parvovirus?

aka Erythrovirus

ssDNA

IP 4-21 days

48

Describe the effect of parvovirus?

Shortens lifespan of RBC progenitors 

Fever 
Rash (slapped cheek) and generalised maculopapular

Arthralgia and rash in adults

Anaemia

49

Describe the effect of congenital parvovirus infection?

Hydrops foetalis (anaemia)

Foetal loss: < 10 weeks: 10%
9-20 weeks: 3%

50

Describe the treatment for congenital parvovirus infection?

Intrauterine infusions 

51

Describe the diagnosis of parvovirus?

SEROLOGY

IgG: past infection, immunity
IgM: acute infection, positive for 2-4 months

NA DETECTION 

US at 1-2 weekly intervals for 6-12 weeks if mother infected

foetal blood smpaling if mother infected 

52

Describe the effects of primary infection with HSV during pregnancy?

Miscarriage

IUGR

Preterm labour (<1%)

53

Describe the effects of primary infection with HSV near the time of delivery?

Three patterns of disease:

Skin-eye-mouth (vesicles, otherwse looks well)
Encephalitis
Disseminated (DIC, hepatitis, very unwell)

54

Describe the management for primary infection with HSV during pregnancy?

Acyclovir treatment and suppression until delivery

Caesarean section 

55

Describe the management of recurrent infection with HSV during pregnancy?

Acyclovir suppression

Avoid instrumentation

Careful clinical examination for lesions at time of delivery

Investigate baby for colonisation 

56

Describe the rates of transmission of syphilis to the foetus at the different stages of the disease?

Primary: 90%
Secondary: 60-90%
Early latent: 40%
Late latent: <10%
Tertiary: rare

57

Describe the outcomes of congenital syphilis?

40% stillbirth

Premature delivery

Early and late onset disease: hepatosplenomegaly, lymphadenopathy, snuffles, rash

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58

Describe the antenatal screening program for syphilis?

Routine screening at first antenatal visit

Repeat at 28-32 weeks and at delivery if at high risk

Repeat with each pregnancy

59

Describe the rate of transmission of chalmydia to the foetus?

50% transmission

25% conjuncitvitis
10% pneumonia 

60

Describe the presentation of toxoplasma gondii infection at birth?

70-90% asymptomatic at birth

May develop symptoms as late as adolescence

Rash, lymphadenopathy, chorioretinitis, hydrocephalus

61

What is the rate of chronic carriage of Hep B in congenitally infected babies?

90% chronic carriage 

62

Describe the antenatal screening for Hep B?

HBsAg screening at first antenatal visit 

63

Describe the treatment for congenital Hep B infection?

Hep B Ig (preferably within 12, def within 48 hrs delivery)

64

Describe the rate of Hep C perinatal transmission?

High viral load: 6%

Undetectable viral load: <1%

HIV coinfected: 10-45%

65

Describe the rate of maternal-foetal transmission of HIV?

0-30%

Dependen on viral load, CD4 count, mode of delivery(Caesarean 0.7 relative protection)

66

Describe how a foetus or neonate can become infected with Group B strep?

Infected via ascending infection or colonised at delivery

20-30% carriage rates in bowel/vagina

 

67

Describe the rate of colonisation of Group B strep in neonates?

How many of these develop disease?

40-70% babies colonised

1% invasive disease 

68

Describe the presentation of Group B strep infection in a neonate?

Pneumonia

Sepsis

Meningitis

69

Describe the maternal risk factors for the development of Group B strep infection in her baby?

Preterm delivery

Prolonged ruptured membranes

Intrapartum fever

Chorioamnionitis

Previous baby with GBS

70

Describe the two presentations of Group B strep infections in neonates?

EARLY ONSET

First 48 hours
Pneumonia and septicaemia
Peripartum infection common

LATE ONSET

Colonisation at birth
Possibly breats milk transmission
Meningitis

71

Describe the treatment for Group B strep infection?

Penicillin and gentamicin

72

Describe how Group B strep presence is detected?

Genital swab > charcoal transport medium > Todd Hewitt broth and antibiotics > orange pigment indicates presence 

PCR detects any that are missed 

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73

For which infections is antenatal serological screening performed/

Rubella

Syphilis

Hep B

Hep C

HIV

May also consider VZV, CMV and toxoplasma gondii