Cytomegalovirus Flashcards
What viral family does cytomegalovirus belong to?
Herpesvirus family (herpes virus 5)
What is the most common virus transmitted to foetus during pregnancy?
CMV
How many women become infected with CMV during pregnancy?
1 in 100
What proportion of maternal CMV infections are passed to the foetus
A third
What percentage of CMV infections passed to the foetus will cause harm?
5%
Infection in which trimester is the highest risk for foetus developing complications of CMV?
1st
Describe the clinical features of cytomegalovirus
Asymptomatic in immunocompetent individuals
Mild flu like illness
Mononucleosis syndrome - splenomegaly, fever, impaired liver function
What investigations can be done for CMV?
Viral serology - CMV specific IgM and IgG - presence of CMV specific IgG in mother previously seronegative or presence of CMV IgM and low IgG avidity <30% (strength with which the antibody binds to the antigen)
Describe the management of CMV
Maternal - no treatment as anti-CMV drugs are teratogenic and have haematological and renal toxicities
Foetal CMV - termination of pregnancy offered or serial ultrasound scanning to assess for manifestations of congenital CMV
How is foetal CMV diagnosed?
Amniocentesis and PCR of the amniotic fluid
When is amniocentesis carried out and why?
> 21 weeks gestation
Foetal kidneys are required for the virus to be excreted into the amniotic fluid
List the problems neonates born with intrauterine CMV infection can have
IUGR Hepatosplenomegaly Thrombocytopenic purpura Jaundice Microcephaly Chorioretinitis
What is the mortality rate for symptomatic congenital cytomegalovirus
20-30%
What is mortality from CMV usually due to?
DIC, hepatic dysfunction and/or bacterial superinfection
What percentage chance do babies born without CMV symptoms have of developing sequalae within 2 years?
10-15%
