Congenital perinatal infections Flashcards
by what means does vertical transmission of infections take place?
between mother and baby/fetus, either via breastmilk (postnatally) or via transplacentally (prenatally). Note: an ascending infection involves vaginal pathogens producing a fetal infection
what does this child suffer from
varicella zoster virus
what is vzv? how is it contracted? how does it present? where is the virus housed in latent infection?
herpesviridae family, dsDNA, enveloped virus.
presents as chicken pox or herpes zoster (shingles).
chickenpox is spread by direct contact, respiratory. presents as fever, lethargy and pruritic vesicular rash lasting 2-6 days. (IP 10-21 days),
More severe in adults (but less common)
latent infection in dorsal root ganglion.
what are complications of chickenpox (VZV)?
- secondary bacterial infection when vesicles lyse.
- commonly strep pyogenes
- staph aureus –> bullous varicella - pneumonitis
- 25x more common in adults (related to smoking) - Acute cerebellar ataxia
- immunological complication, self limiting ataxia
How does varicella affect the fetus?
- deaths most common in 3rd trimester
- 1st trimester primary infections may cause deformities (cicatrical scarring, limb hypoplasia, microcephaly, cataracts, mental retardation, GI and genitourinary malformations)
at what point is maternal varicella a great concern for perinatal transmission?
when primary infection is contracts -7 to 2 days of delivery before moter has a chance to mount an immune response.(lacks the specific antibody against it)
17-30% chance of transmission
30% chance of mortality
who is a good candidate for prophylactic varicella zoster immunoglobulin tx?
received from immune donors, given to non immune people after exposure within 10 days.
Target:
- premature babies
- susceptible pregnant women
- infants whose mothers develop varicella within 7 days of pregnancy or first month of life
- immunocomporomised
NB: prolongs IP to 30 days
how is acute varicella treated?
- oral acyclovir if <24hrs with rash and no systemic symptoms
- IV if pneumonitis, neurological symptoms, organ involvement, hemorrhagic rash
T/F there is no vaccine for CMV.
FALSE.
vaccine is a live attenuated virus
–>(MMR at 8 months) MMRV at 12 months
2 doses if older than 14 yrs.
For those in high risk occupations:
booster for adults older than >60yrs, 14x more potent than child vaccine (b/c harder to mount a response in adult who has been exposed previously)
what is cmv?
how is CMV transmitted?
NB: recurrent infections may occur due to reactivation of previous infection or reinfection (b/c no cross protection b/w various strains)
who is at highest risk of developing/contracting CMV?
risk increases with age up to childbearing years.
In developed countries its highest in adulthood.
in developING countries it’s highest before age 3.
a fetus contracts CMV, what are the chances this stemmed from the mother contracting a primary infection vs had a reactivation of previous infection?
10-30% of cases are a reactivation
…result in 1-3% fetal infection
1% are primary infections
…result in 20-50% fetal infection
how is CMV acquired postpartum? how does it present?
via breastmilk.
presents as sepsis like sympoms:
- hepatomegaly
- resp distress
- atypical lymphocytosis
how is CMV best diagnosied?
IgG and IgM can give an indication of presence of current or past infection or reactivation of infection. Several confounders such as rheumatoid arthiritis (produces IgM), false positives/negatives, also IgM can remain for up to a year in CMV cases.
PCR of amniotic fluid is very sensitive after 20/40 (95%).
Fetal cord blood analysis for IgM has less sensitivity than PCR also risk of miscarriage.
suppose a mother with CMV has a baby who is normal at birth, what are the consideration to make?
considering 90% of neonates can be asymptomatic at birth (with 10-15% having long term sequelae) its important to monitor for development of complications….
- deafness may be delayed 5 yrs, should undergo serial audiometry
- chorioretinitis/optic atrophy in 2% of cses, should undergo serial ophtho exams
- microcephaly and developmental delay. should undergo seial psychomotor assessment
- pneumonitis at 1-4 months, rare
what is rubella? how is it transmitted? how does it present?
aka “ german measles”
transmitted via nasal secretions.
25-50% infections are asymptomatic. Infectious from -7 to +14 days (before symptoms arise).
during which congenital period is risk of rubella damage highest?
risk of damage highest before 4 weeks (85%)
risk wanes after 16 weeks.
[….] also known as erythrovirus is a ssDNA virus that targets and shortens lifespan of RBC progenitor cells.
Parvovirus
How does parvovirus present clinically?
Erythema infectiousum, characteristic ‘slapped cheek’
what are the features of congenital parvovirus?
hydrops foetalis (anaemia)
NB: 60-70% of women are immune. foetal loss occurs in 10% of cases before 10 weeks gestation.
how is parvovirus diagnosed (ie serology)?
what is the impact of primary herpes simplex virus if infected during pregnancy? near delivery?
how should herpes simplex be managed during pregnancy? primary vs recurrent infection
which STI might present this way?
Treponema Pallidum (syphilis)
the [….] form/phase/stage of syphilis is most commonly transmitted to fetus. The most common outcome of congenital syphilis infection is […], followed by premature delivery and late/early onset disease.
primary.
still birth.
