Rubella

Question 1

Incubation period Rubella?

Answer 1

14-21 days

Question 2

Infectious period for Rubella?

Answer 2

One week before symptoms to 4 days after rash appears.

Question 3

Clinical syndrome with Rubella?

Answer 3

Prodromal low grade fever, malaise, coryza and mild conjunctivitis. Transient, erythematous rash, starting behind the ears and usually spreading to face and necklace area. May be associated with pre or post auricular lymphadenopathy.

Question 4

Complications of Rubella (non pregnant)?

Answer 4

Haemorrhagic complications due to thrombocytopenia
Encephalitis rarely

Question 5

Complications or Rubella in pregnancy and relative rates?

Answer 5

Congenital Rubella Syndrome
- Cataracts, infantile glaucoma
- Deafness
- Microcephaly, developmental delay
- Congenital heart disease

First 8-10 weeks - 90% of foetuses will have abnormalities (often multiple), miscarriage common
11-16 weeks - 10-20% chance of abnormalities
16 weeks on - damage rare - only deafness reported

Question 6

Preg patient with erythematous rash over face and neck, fever and some joint pain. What tests, what followup?

Answer 6

B19 IgG and IgM, Rubella IgG and IgM.

If Rubella negative or only IgM pos then repeat in 4 weeks. If IgM only then looking for seroconversion to IgG. If both pos on both then avidity can be done as avidity matures over a few weeks.

If B19 IgM pos then confirmatory testing is required (PCR or evidence of seroconversion from booking blood). Either PCR or demonstrating seroconversion from booking blood.