Congenital and Perinatal Infections Flashcards
Describe the characteristics of VZV
Herpesviridae
Enveloped dsDNA virus with icosahedral capsid
Where does latent VZV reside?
DRG
How long do chickenpox symptoms usually last?
2-6 days
List 3 complications of chickenpox
Secondary bacterial infection
Pneumonitis
Acute cerebellar ataxia (self-limiting, resolves within weeks)
What are the most common secondary bacterial infections in chickenpox?
S. pyogenes
S. aureus (bullous varicella)
What is an independent variable for maternal varicella?
Smoking
What symptoms are experienced by pregnant woman with varicella?
Respiratory symptoms day 2-5 (productive cough with haemoptysis)
When are deaths from maternal varicella most common?
In 3rd trimester
List 6 sequelae of a 1st trimester primary infection causing congenital varicella syndrome
Limb hypoplasia Cicatricial scarring Microcephaly Cataracts Mental retardation GI and genitourinary abnormalities
When is perinatal varicella a risk?
With a primary (i.e. no specific Ab) maternal infection -7 to +2 days from delivery
What does perinatal varicella cause?
Disseminated infection with 25-30% mortality rate (even with treatment)
When is prophylactic VZIG given?
<96hrs post-exposure
In what groups is prophylactic VZIG given?
Susceptible pregnant women
Infants whose mothers develop varicella <7 days prior to delivery and in 1st month of life
Immunocompromised
Premature babies
What is the effect of VZIG?
Prolongs incubation period to 30 days
How is acute varicella treated?
Acyclovir
When is oral vs. IV acyclovir used for varicella?
Oral: <24hrs of rash and no systemic symptoms
IV: pneumonitis, neurological symptoms, organ involvement, haemorrhagic rash
Describe the characteristics of the varicella vaccine. When is it given?
Live attenuated virus (OKA strain)
Seroconversion >90%
Given at 18 months (if >14, 2 doses given)
Describe the characteristics of CMV
Herpesviridae
dsDNA with icosahedral capsid
Is congenital CMV a developed or developing country problem?
Developed - in developing countries most women of reproductive age have already acquired immunity
List 4 routes of CMV transmission
Transplacental (haematogenous spread)
Perinatal (genital secretions, breast milk, saliva)
Toddlers in day-care
Adults via sexual or non-sexual close contact
What does postpartum CMV cause?
Sepsis-like syndrome (hepatomegaly, respiratory distress, atypical lymphocytosis)
What is the difference between primary and reactivation of CMV in terms of the % of women affected and the % of foetal transmission?
Primary: 1% of women, 20-50% foetal infection
Reactivation: 10-30% of women, 1-3% foetal infection
What are some of the possible sequelae of congenital CMV?
Sensorineural deafness
Learning difficulties
Seizures
How long is IgM detectable for in a primary CMV infection?
Can be detectable for months
How can foetal CMV infection be confirmed?
PCR on amniotic fluid
Testing foetal cord blood
What is done in the case of congenital CMV?
Counselling
Serial ultrasound
What tests are performed at birth if the baby has congenital CMV but is not symptomatic?
Serial audiometry
Serial visual assessment
Psychomotor assessment
Monitor for pneumonitis
What tests are performed at birth if the baby has congenital CMV and is symptomatic?
Confirm diagnosis with CMV detection in urine
Perform cranial ultrasound + other imaging
Multidisciplinary approach to management
When is ganciclovir administered for CMV? What are the concerns?
Only to symptomatic neonates (via IV)
Concerns about carcinogenicity and reproductive toxicity
Describe the characteristics of rubella
Togavirus
Enveloped ssRNA
When are individuals infected with rubella considered infectious?
-7 to +14 days from onset of nasopharyngeal secretions
What is the clinical presentation of rubella?
Low-grade fever
Lymphadenopathy (occipital, postauricular, posterior cervical)
Exanthem (maculopapular)
Polyarthralgia/arthritis
When is risk of damage due to congenital rubella syndrome highest?
16 weeks)
What is the classical triad of congenital rubella syndrome?
Opthalmological (cataracts, glaucoma, retinopathy)
Cardiac (patent ductus arteriosus, PA stenosis)
Auditory (sensorineural deafness)
What are some symptoms of congenital rubella syndrome other than the classical triad?
Neurological (meningoencephalitis, behavioural)
Others (rash, thrombocytopaenia)
Late endocrinopathies (DM, thyroid dysfunction)
How is rubella prevented?
Live attenuated vaccine (highly effective)
Seronegative women are vaccinated postpartum
Describe the characteristics of parvovirus
ssDNA
What is fifth disease? What are the symptoms?
Erythema infectiosum, caused by parvovirus
Symptoms include fever, “slapped cheek” rash and generalised macropapular lace-like lash, arthralgia in adults, and acute aplastic crisis in those with chronic haemolytic anaemias
What does congenital parvovirus infection cause?
Hydrops foetalis
How is foetal loss prevented in congenital parvovirus infection?
Intrauterine transfusions
How is congenital parvovirus diagnosed?
Ultrasound at 1-2 weekly intervals for 6-12 weeks
Foetal blood sampling
Intrauterine transfusion
What does a primary HSV infection during pregnancy cause?
Abortion, IUGR, preterm labour
What does a primary HSV infection close to delivery cause?
Skin-eye-mouth disease
Encephalitis
Disseminated (hepatitis, DIC)
How is primary HSV infection during pregnancy managed?
Acyclovir treatment and suppression until delivery
C section
How is recurrent HSV infection during pregnancy managed?
Acyclovir suppression
Avoid instrumentation
Careful clinical examination for lesions
Investigation of baby for colonisation
What are the 3 main outcomes of congenital syphilis infection?
Stillbirth
Premature delivery
Early- and late-onset disease
What are 3 benefits of antenatal screening for syphilis?
To prevent congenital infection
To prevent further sexual transmission
To prevent progression to tertiary syphilis
When is syphilis screening performed?
Routine at 1st antenatal visit
Repeat at 28-32 weeks and delivery if high risk (young, single, low SES, etc)
Repeat with each pregnancy
What are the outcomes of congenital infection with toxoplasma gondii?
70-90% asymptomatic at birth
Rash, chorioretinitis, hydrocephalus
Describe the characteristics of hepatitis B
Glycolipid-enveloped ds DNA virus
What increases the risk of hepatitis B transmission?
HBeAg or PCR+ women have greater risk of transmission
What is done if maternal hepatitis B infection is diagnosed?
Infant is vaccinated at birth, 2, 4 and 6 months (performed universally anyway)
Hepatitis B Ig (BIG) is administered with 12-48hrs of delivery
What factors influence maternal-foetal transmission of HIV?
Viral load
CD4 count
Duration of ruptured membranes
Mode of delivery
What % of babies are colonised with Group B streptococcus at birth? How many of these develop invasive disease?
40-70%
1%
What symptoms are seen in peripartum GBS infection?
Pneumonia
Sepsis
Meningitis (more common with late-onset infection)
List 5 maternal risk factors for transmission of GBS to baby
Preterm delivery Prolonged ruptured membranes Intrapartum fever Chorioamnionitis Previous baby with GBS
How is GBS infection treated?
Penicillin and gentamicin
How is GBS infection prevented?
Intrapartum chemoprophylaxis (screening for carriage and administration of antibiotics)
What antenatal serological screening should be routinely performed, either pre-conception or at the 1st antenatal visit?
Rubella Syphilis HBV HCV HIV
