CMV TOG Flashcards
How common is CMV in developed countries?
0.5% of live births
What type of virus is CMV?
ds DNA
What are the major consequences of CMV?
Hearing loss, neurological impairment
What is the most common source of CMV infection?
Saliva and urine of young children
What are the symptoms of CMV infection
Asymptomatic in 90%
fever, joint aches, malaise, lymph nodes
Clinical features of CMV at birth?
Most have no clinical features at birth but later develop some degree of hearing loss.
Some have jaundice, petechial rash, blueberry muffin rash, hepatosplenomegaly, microcephaly, SGA
How does transmission to baby occur?
transplacental, during labour (secretions, blood), breast milk
When is the fetal transmission risk highest?
3rd trimester (66% transmission)
Primary infections
When does infection result in worst severity of disease in baby?
First trimester
22% have hearing loss/neurodevelopmental impairment
Ultrasound features of CMV?
ventriculomegaly, microcephaly, calcifications, intracranial haemorrhage, echogenic bowel, FGR, hydrops
IgG/IgM rules for CMV
IgM may persist for MONTHS after primary infx and may be present in non-primary infx
IgM cross-reactivity can occur with other infxs like EBV
Need IgG AVIDITY testing to define infection timing (before or during pregnancy) - high avidity=previous infx, LOW avidity=recent primary infx
How can you diagnose primary CMV infx?
CMV IgG in women previously seronegative
Low IgG avidity
How can you diagnose non-primary CMV infx?
Not by blood test, because IgG is rubbish
Need to do invasive testing
How to check if baby has been infected with CMV?
Amniocentesis 6-8 weeks after maternal infection (after 20w gestation as relies on fetal urine production) - using PCR
How do you continue to monitor a baby with confirmed CMV?
USS every 2-4 weeks
Fetal brain MRI 28-32w
Consider FBS - to check platelet count (low)
