Rubella

Background

  • Rubella is a viral infection caused by Rubiviruses.  In the majority of individuals, it causes mild disease.  However, infection can have severe consequences in pregnancy (see below)
  • As a result of the childhood immunisation programme, rubella is uncommon in the UK (congenital defects are even rarer)
    • Rubella is now notifiable
    • It is much more common in countries which do not vaccinate (be weary of people who have travelled)
    • Also be weary of patients who were not vaccinated as a child (MMR scare scandal)
  • Spread via respiratory droplets although only moderately infectious

Presentation

  • Symptoms/signs are often non-specific for rubella (weigh up the likelihood)
    • Rash
      • Starts often behind the ears, spreading to the head/neck then trunk and extremities.
      • Non-confluent, maculopapular pink rash
      • Transient (3-5 days)
    • Lymphadenopathy
      • May be present before the rash and may last 2 weeks or more after the rash
      • Most often suboccipital, postauricular and cervical
    • Arthritis/Arthralgia
      • More common in affected women (60%)
      • Usually mild and most commonly in the hands, wrists and kness
      • Appears just after rash but may last several weeks
    • Other features include malaise, low grade fever, headache, sore throat, rhinorrhoea and conjunctivitis
  • Consider vaccination status; PMHx of rubella; contact history and recent outbreaks to increase/decrease the probability of rubella as a diagnosis
    • NB Have a low index of suspicion in pregnant women as there are more serious consequences

Investigations

  • Laboratory confirmation (salivary PCR) is the diagnostic test

NB MAKE SURE TO NOTIFY ANY SUSPECTED CASES TO HPS (or other health protection agency e.g. HPU in England/Wales)

Management

  • Usually at home, fluids and bed rest with analgesia as required (e.g. paracetamol)
  • Rarely, rubella can cause a thrombocytopenia which may require hospitalisation (more common in children) or encephalitis (likewise but in adults)

Rubella in Pregnancy

  • If a pregnant women comes in contact with rubella
    • The majority of foetuses will be normal but
      • The highest risk of foetal damage is in the first trimester (around four weeks- risk is about 50%; although NICE quotes 90% of foetuses being affected by congenital rubella syndrome if contracted before 11 weeks- dramatically dropping to 33% at 11-12 weeks and 11% at 13-14 weeks); risk decreases after first trimester (after 20 weeks the risk is minimal)
        • Mothers who have been exposed in the first trimester are at high risk of spontaneous abortion (20%)
  • Congenital Rubella Syndrome
    • Transient neonatal problems include
      • Low birth weight
      • Hepatosplenomegaly (and early jaundice)
      • meningoencephalitis
      • thrombocytopenia
    • Permanent abnormalities include
      • Heart defects e.g. PDA; pulmonary artery stenosis; pulmonary arterial hypoplasia
      • Eye defects e.g. cataracts; iris hypoplasia; retinopathy
      • CNS e.g. microcephaly; mental/developmental retardation
      • Senorineural deafness
    • Other features which may develop later include
      • Immunological problems
      • Diabetes mellitus
      • Panencephalitis
  • NB Once born, the baby should be isolated if the mother is non-immune

Investigation/Management in Pregnancy

  • Notify and test for rubella (and parvovirus B19 which can present similarly) in suspected cases
    • Explain the risk of outcomes (appropriate for gestational age) and explain that there is no active treatment for rubella
      • If after 20 weeks gestation, explain that there have been no cases of CRS
    • Assess risk based on immunity status (rubella should have been tested as part of routine antenatal assessments)
      • If the patient is immune, still contact HPS as parvovirus should also be tested for.  The risk of rubella in women who are antibody positive on at least 2 occasions (prior to this) is low (immunity)
  • Refer urgently to obstetrics if the women is confirmed rubella and is 20 weeks or less.  They should be counselled of the risks and offered appropriate options.
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