Measles

Original article by Tom Leach | Last updated on 27/5/2014
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Introduction

  • Now relatively rare in the UK
  • Older children have more severe disease
  • Caused by the Morbillivirus, which is a type of paramyoxovirus
    • This is a single stranded, enveloped RNA virus
  • It is a highly contagious infection of the respiratory system, and can be passed on by airborne transmission, via droplets expelled in coughing, sneezing and respiration.
  • Maternal antibodies tend to provide immunity in the first 6 months of life
  • In the developing world, the death rate is approx 10%
 

Disease progression and symptoms

  • Incubation period is typically 10-14 days, followed by the symptomatic phase, of typically 7-10 days.
  • Patient is infective for the last 2 days of incubation (i.e. before symptoms are apparent!), and for the first 6 days of the symptomatic phase.
  • Fevertemperature increases from day 1-5, peaks at day 5, before falling.
  • Koplik’s spots –these are small white spots on the buccal mucosa. Visible usually from days 2-5. These are diagnostic for measles, but often not seen, and when present are transient.
  • Cough – usually apparent through the whole symptomatic phase
  • Conjunctivitis and Coryzal Symptoms – days 1-5.
  • Rash! – this usually starts off behind the ears, and spreads down the body. Initially a maculopapular rash, it typically expands and becomes indistinct. Usually lasts from about days 3-7, but there is a possibility of desquamation towards the end.
  • When to exclude from school?
    • Until at least 5 days after the onset of the rash. Typically, viral shedding stops around day 6, and the rash starts at day 3. This allows 2 days leeway, excluding the child from school until at least day 8. 
 
 

Complications

  • Encephalitisoccurs in 1 in 5000 cases. Presents 8 days after the onset of symptoms of measles, with lethargy, headache and irritability. Can result in LOC and coma. 15% mortality rate. In up to 40% of cases there will be long-term problems, including; deafness, hemiplegia and learning difficulties.
  • Subacute sclerosing panencephalitis (SSPE) extremely rarePresents approx 7 years after measles infection. Will cause progressive dementia (over several years) and eventual death. Occurs in 1 in 100 000 cases of measles. Caused by a measles virus variant gaining access to the CNS. Diagnosis is confirmed by high levels of measles antibody in the blood and CNS. May also cause CNS abnormalities.
 

Treatment

Essentially supportive
  • Ensure isolation in hospital – to prevent the child coming into contact with immunocompromised patients!
  • Ensure adequate nutrition – continue breastfeeding, even with diarrhoea, supplement and intubate if necessary.
  • Vitamin A – involved in the immune response, and may be deficient in some, but rarely in the developed world. Supplements available if you suspect it may be a contributing factor
  • Ribavirin – antiviral. Should not be used in normal cases, but should be used in immunocompromised patients.
 

Vaccination in the UK

  • Began in UK in 1960’s
  • 800,000 cases/year before vaccination programme
  • Almost 100% of children used to get it at some point!
  • 3,000 cases of measels in the UK in 1990’s
  • Number of cases has risen slightly after fall in MMR uptake in late 1990’s
  • No link between MMR and autism
  • Live attenuated vaccine used – highly effective, and provides life-long protection. The percentage needed to vaccinate for herd immunity is >80%.
  • In 10-20% of cases, immunity is not achieved after this first dose, hence the ‘booster’ given to children just before they begin attending school (Age 3 years 4 months)
  • Side effects can include mild variants of the symptoms of the disease being vaccinated against. For example, they can include; rash, fever, and loss of apetite (measels). swollen lymph nodes (mumps), and rarely stiff, swollen joints (rubella).