Rubella

Question 1

1) What is rubella (german measles)?

Answer 1

• It is a viral exanthem caused by a togavirus
• It is seen less frequently in GP due to immunisation

Question 2

Describe the aetiology of rubella

Answer 2

• It is spread by droplet from the nose and throat from infected contacts
• 1/3rd of infection is subclinical
• Infection confers lifelong immunity
• Incubation period is 14-21 days

Question 3

What are the clinical features of rubella?

Answer 3

• Generalised maculopapular rash (not confluent) first appearing on the neck and face and spreads to trunks and extremities
• No prodrome
• Reddened pharynx
• Low grade fever
• Small joint polyarthritis, headache, myalgia and conjunctivitis
• Post-auricular, suboccipital and postcervical lymphadenopathy
• Infectious upto 7 days before and for 5 days from onset of rash
• No staining or desquamation of skin
• 1/3 can be subclinical

Question 4

How to diagnose?

Answer 4

• Clinical features
• Rubella serology (IgG and IgM) or virus culture

Question 5

How to manage rubella?

Answer 5

• Symptomatic management including rest, paracetamol as rubella is a mild disease
• Child excluded from school until fully recovered or upto 5 days form onset of the rash

Question 6

Who are the high-rsk groups for rubella?

Answer 6

• Travellers to and from areas where rubella vaccination is not widespread
• Childcare workers
• Health care workers
• Unborn babies whose mothers have low or non-existent

Question 7

Key features in history of patient to arrive at a diagnosis of rubella?

Answer 7

• Immunisation status
• Travel history
• Examination of the nature of the rash and associated symptoms
• Previous rubella infection

Question 8

What is the indication for rubella vaccine in Australia?

Answer 8

• 12 months-MMR
• 18 months MMRV
• 4 years MMR
• Catch up vaccination upto age of 9 years
• Women planning pregnancy or shortly after delivery if no immunity to rubella (2 doses 1 month apart)
• Aborginal people, refugees and asylum seekers eight years and over can get catch up vaccination
• MMRV not recommended over 14 years
• Adults born before 1966 do not need rubella vaccine
• People working with children

Question 9

What are the contraindications to rubella vaccine?

Answer 9

• HIV or AIDS infection
• Pregnancy
• On high dose corticosteroids
• On immunosuppressive treatment such as chemotherapy
• Having a malignancy such as Hodgkins
• Immunodeficiency with extremely low levels of antibodies such as hypogammaglobulinaemia

Question 10

What are the complications of rubella?

Answer 10

• Usually recover within three days
• Otitis media and encephalitis (rare 1 in 5000)
• Polyarthritis
• Congenital rubella syndrome when mother contracts the infection during the first 10 weeks of pregnancy. Birth defects include deafness, blindness, intellectual disability, heart defects and impaired growth

Question 11

How to manage rubella exposure in pregnancy?

Answer 11

• If immune status known and immune- No risk to the foetus
• If immune status unknown- rubella serology is the next step
• Rubella IgM rises 7-10 days after infectionand indicated recent infection; hence repeat test i 14-21 days
• No apparent risk after 19 weeks; upto 85% risk <12 weeks and falls to 10% at 19 weeks.
• If IgM found positive, isolate, notify PHU and urgent referral to Paediatrician for counselling; termination offered if first trimester, fetal tesint in second trimester
• Avoid exposure to anyone with rubella/rash if not immune

Question 12

How to interpret rubella serology?

Answer 12

• IgG and IgM negative-susceptibe to infection
• IgG and IgM positive-reinfection/recent infection
• IgG negative and IgM positive-Recent infection
• IgG positive and IgM negative-Previous infection/immunisation
• Always retest in 14-21 days