Rubella

Question 1

Rubella

Type of virus and transmission

Answer 1

RNA togavirus

Nulliparous women more susceptible than multiparous - due to successful childhood and postnatal vaccination.

Risk in pregnancy is 2:1000 in susceptible women.

Transmission - Nasopharyngeal secretions -> UTRI -> viral dissemination
· Asymptomatic
· Symptomatic - infective 10days prior to rash onset until 7days after
· Vertical transmission
· Congenital infection - infectious for months

· If previous infection, risk of re-infection, fetal risk is low <10%

Question 2

Rubella

Features of maternal infection

Answer 2

25-50% asymptomatic

Febrile illness
Conjunctivitis
Adenopathy - posterior
Widespread maculopapular rash - face then arms/trunk

Question 3

Rubella

Features of congenital infection
Neonatal features

Answer 3

SPECTRUM:

- IUGR
- Meningoencephalitis
- Cataracts
- Retinopathy
- Hearing loss 60%
- Cardiac defects - septal, pulmonary stenosis
- Hepatosplenomegaly
- Bone radiolucencies
- Thrombocytopaenia
- Dermal erythropoiesis
- Adenopathy
- Interstitial pneumonia
- Intellectual disability
- Insulin dependent diabetes mellitus
    - Thyroid disorder

Neonatal:

• blindness
• deafness
• blueberry muffin rash

Question 4

Rubella

Risks of infection in 1st trimester

Answer 4

HIGHEST in 1st trimester

80% fetal infection
85% risk fetal defect, severe

Question 5

Rubella

Risks of infection in 2nd trimester

Answer 5

Infection risk and complications progressively improve

13-16 weeks
54% fetal infection
35% risk complication

17-22 weeks
30% fetal infection
Complications rare

Question 6

Rubella

Risks of infection in 3rd trimester

Answer 6

~100% fetal infection

Complications rare

Question 7

Rubella

Investigations

Answer 7

IgM: +ve in 5days. NB can be false +ve.
IgG: +ve within 1-2 weeks, lifelong usually

IgG avidity:
High = infection >3months prior
Low = infection more recent <3months

Question 8

Rubella

Management

Answer 8

• Amniocentesis or CVS to confirm fetal infection with PCR
>6weeks post maternal infection
CVS risk false +ve from maternal contamination

• Manage mother symptomatically
• Isolate in droplet precautions for 7days after rash onset
• Offer TOP depending on gestation and severity
• No fetal treatment exists

Question 9

Rubella

Prevention

Answer 9

• Vaccination
NOT suitable in pregnancy as attenuated live vaccine.
Fine to be given any time post partum.

• Screen immunity pre or at beginning of pregnancy
Know susceptibility, vaccinate if low or not-immune pre-pregnancy OR post partum

• No benefit from post exposure prophylaxis
• Ensure healthcare workers vaccinated

Question 10

Rubella

Management at birth

Answer 10

• Ensure attendants vaccinated and adequate antibodies
• Hearing screen, ophthalmological screen, cardiac assessment
  • At birth
  • Regularly to ensure no sequelae develop
• Serology with IgM
• Urine and throat culture for PCR
• Breastfeeding fine
• Check household contacts and caregivers are immune
• Caution if infected infant - around other infants and pregnant women for ~12months