Rubella

Question 1

What is rubella caused by?

how is it transmitted?

Answer 1

• RNA virus (rubivirus togaviridae)

- airborne droplet transmission between close contacts

Question 2

What is the incubation period for rubella?

Answer 2

• 14-21 days with patients being infectious for 7 days before and 4 days after symptoms

Question 3

what can an infection in pregnancy cause?

Answer 3

• congenital rubella syndrome

- endemic in developing countries

Question 4

what are the initial symptoms?

how does the rash look?

Answer 4

• low grade fever
• headache
• mild conjunctivitis
• lethargy
• anorexia with rhinorrhoea
• pink discrete macule that coalesce
• stats behind the ears and face, spreading to trunk and extremities

Question 5

what symptom will rubella patients get that are not in the head?

Answer 5

• cervical, sub occipital and post auricular lymphadenopathy may precede rash
• arthralgia
• Forchheimers sign: petechiae on the soft palate, not diagnostic of rubella
• rash usually develops 14-17 days after exposure to virus

Question 6

what is the gold standard test to confirm rubella?

what will you see on an FBC?

Answer 6

• serological and PCR testing

- low WCC, increased proportion of lymphocytes and thrombocytopenia

Question 7

how can it be managed?

Answer 7

• antipyretics (avoid aspirin)
• keep child off school for 7 days after rash appears
• infection in the pregnant woman should be investigated

Question 8

what complications can you get?

Answer 8

• rubella encephalopathy (6 days after rash)
• arthritis and arthralgia
• thrombocytopenia
• Guillian-Barre Syndrome
• Panencephalitis

Question 9

what clinical features might you see in the pregnant woman with rubella?

Answer 9

• macular rash prodrome, and posterior auricular lymphadenopathy
• arthralgia in wrist and hands
• 20-50% of all rubella infections are subclinical

Question 10

at what gestations are foetus’ likely to get serious damage or death when mum has rubella?

Answer 10

• week 8-10 (90% will have damage)
• 11-16 weeks (10-20% will have damage)
• foetal damage is rare over 16 weeks

Question 11

what transient features might they have?

Answer 11

• IUGR
• thrombocytopenic purpura (“blueberry skin”) in 25%
• haemolytic anaemia
• hepatosplenomegaly
• jaundice
• radiolucent bone disease
• meningoencephalitis (25%)

Question 12

what developmental issues might they have?

Answer 12

• sensorineural deafness, most common cause of congenital deafness in the world
• general learning disability (55%)
• IDDM (20%, often delayed till adolescence)
• late-onset disease at 3-12 months, with rash, diarrhoea, pneumonitis and high mortality

Question 13

What permanent congenital issues will they suffer from?

Answer 13

• congenital heart disease (PDA or pulmonary artery stenosis)
• eye defects: cataracts, congenital glaucoma, microphthalmia, myopia
• microcephaly

Question 14

what features do all the TORCH viruses have in common?

Answer 14

• preterm delivery
• low birth weight
• anaemia
• thrombocytopenia
• hepatitis with jaundice and hepatosplenomegaly
• microcephaly, mental handicap, seizures, failure to thrive

Question 15

what investigations would you perform?

Answer 15

• serological and PCR

- detection of IgM in saliva

Question 16

how do you know if it occurred postnatally or antenatally?

Answer 16

• IgM antibodies do not cross placenta and indicate a recent infection acquired after birth
• unexpected persistence of rubella IgG (should drop off if no virus)
• PCR testing

Question 17

how can CRS be managed?

Answer 17

• termination of pregnancy if positive IgM in first 16 weeks of pregnancy
• cochlear implants and cardiac surgery

Question 18

what is normally done in antenatal care to check for rubella?

Answer 18

• checking rubella antibody status