Congenital Infections Flashcards
What is the incidence of primary VZV infection in pregnancy?
3:1000
RCOG GTG
What type of virus is VZV?
DNA virus
Herpes family
How is VZV transmitted?
Highly contagious
Respiratory rollers
Direct personal contact with vesicle fluid
Indirectly via fomites
How does the primary infection of VZV present?
Fever
Malaise
Pruritic rash that develops into crops of maculopapules, which become vesicular and crust over before healing
What is the incubation period of VZV?
1-3 weeks
When is VZV infectious?
48 hours before the onset of the rash
Until the vesicles crust over (usually within 5 days of appearing)
What type of vaccine is the VZV vaccine?
Live attenuated vaccine
How long should women be advised to avoid conceiving for, after having the VZV vaccine?
4 weeks
What are risk factors for serious morbidity from primary VZV infection in pregnancy?
Second half of pregnancy
Immunocompromise (including systemic steroids within the last 3 months)
Smoking
Chronic lung disease
If a woman has been exposed to VZV, what should be offered? (And when and how does it work?)
VZIG
Varicella zoster immunoglobulin
ASAP, but up to 10 days after exposure (or up to 96 hours *ASID)
A second dose may be required if a further exposure is reported and 3 weeks have elapsed since the last dose
Human immunoglobulin product from plasma donors
Prevents or attenuates chickenpox in non-immune individuals
May reduce the risk of development of FVS (Fetal Varicella Syndrome)
What are the manifestations of severe VZV infection in adulthood?
Pneumonia
Hepatitis
Encephalitis
Death (rare)
What should a pregnant women be offered if she develops a chickenpox rash, and presents within 24 hours of the onset of the rash?
Oral Aciclovir
Synthetic nucleoside analogue
Inhibits replication of VZV
RCT: reduces duration of fever and symptomatology when compared to placebo
Accumulating data: no risk of major fetal malformation
What should a pregnant woman be offered if she develops severe VZV infection?
IV Aciclovir
Synthetic nucleoside analogue
Inhibits replication of VZV
Accumulating data: no risk of major fetal malformation
Up to what gestation, is there a risk of developing FVS with VZV?
28/40
What are the benefits and disadvantages of amniocentesis in the context of VZV in pregnancy?
VZV PCR
High sensitivity but low specificity
Good negative predictive value but poor positive predictive value
What are the manifestations of Fetal Varicella Syndrome?
Skin scarring in dermatomal distribution
Eye defects: microphthalmia, chorioretinitis, cataracts
Limb hypoplasia
Neurological abnormalities: microcephaly, hydrocephalus, cortical atrophy, mental retardation, dysfunction of bowel and bladder sphincters
With VZV in pregnancy, where should regional analgesia be performed?
At a site free of cutaneous lesions
Which neonates should receive prophylaxis with VZIG +/- aciclovir
For babies born to mothers who have had chickenpox within the period 7 days before delivery and up to 7 days post-delivery (up to 2 days from ASID)
(RCOG)
AND
Maternal chicken pox >2-28 days after delivery if infant <28 weeks or <1000g BW
What is the leading cause of congenital infections?
What is its prevalence?
CMV
0.64 - 0.7%
What is the meaning of CMV specific IgG avidity? What information does it provide?
Low avidity: recent primary infection
Intermediate avidity: recent primary infection cannot be excluded (manage as primary infection)
High avidity: past infection
How does CMV normally present?
Asymptomatic
Viral illness associated with atypical lymphocytosis
What is the difficulty with interpreting CMV IgM?
CMV IgM can persist for months after primary infection, or reappear with reactivation or re-infection
CMV IgG Avidity may assist in timing of CMV infection
Of all women with positive CMV IgM, only 25% are eventually diagnosed with a primary infection
What are risk factors for maternal CMV acquisition?
Frequent, prolonged contact with young children (in particular, those shedding CMV)
Day care workers
Parents with child in day care
Immunocompromised
Blood transfusions
Sexual contact
What is the % risk of congenital CMV infection to a fetus if mother has secondary CMV infection?
1%