Rubella Flashcards
Define
RNA virus with incubation period 6-21 days, infectious from 1 week prior to 5 days after onset of rash
Aetiology – transmission by aerosol route, vertical (transplacental)
- Necrotic change in the placental cells –> spread to vessels causing emboli which is transported to the foetus –> foetal infection interferes with development of organs and reduces rate of cell division (structural malformations) and the total number of cells (small babies)
Risk factors – non-immunity (increased rates in ethnic minorities)
Epidemiology – RARE – 97% women are vaccinated or immune in the UK
Signs and Symptoms
Coryzal symptoms (cold-like symptoms, fever, malaise), arthralgia, rash
Soft palate lesions (20% with Forchheimer spots)
Lymphadenopathy
Maculopapular rash (starting behind ears, spreading to head and neck, then to rest of body)
- Called “German Measles” because the rash mimics the measles rash and spreads in the same fashion
Congenital Rubella Syndrome (CRS) -> Classic triad: sensoineural deafness, cardiac disease (PDA, VSD), eye abnormalities (cataracts, retinopathy)
Infection <12w GA (critical organogenesis stage) -> CRS(90%), microcephaly, (20% miscarry at this stage)
Infection 12-20w GA (CNS development) -> deafness, chorioretinitis /cataracts
Infection >20w GA (growth) -> low risk
Investigations
Blood serology – IgG and IgM (active; or 4x increase in IgG titre)
PCR virus
USS – foetal anomalies
Screening
- Screening not routinely offered (prevalence too low)
- For women screened and rubella antibody NOT detected MMR after pregnancy
- Vaccine contraindicated IN pregnancy because it is a live vaccine
Management
Rest, fluids and paracetamol [no treatment]
Offer TOP if <16wGA
16-20 weeks: low chance of deafness occurring, prenatal diagnosis of foetal rubella infection required
Performed by RT-PCR on amniotic fluid samples
If transmission to foetus confirmed: options include TOP or ultrasound surveillance for features of CRS
Refer to Foetal Medicine Unit and notify the Health Protection Unit (HPU) – notifiable condition
- suspected cases should be discussed immediately with the local Health Protection Unit (HPU) as type/timing of investigations may vary
- Avoid work and pregnant women for 4 days after initial development of the rash
No MMR vaccination (or any live attenuated vaccine) to be given during pregnancy/immunocompromised
Give in post-natal period
Complications
Maternal – miscarriage, pneumonia, arthropathy, encephalitis, ITP
Foetal – death, congenital rubella syndrome (deafness, VSD, PDA, cataracts, CNS defects, IUGR, hepatosplenomegaly, thrombocytopenia, rash)
