Measles (Rubeola)

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Introduction

  • An acute viral infection caused by an RNA virus of the genus Morbillivirus in the family Paramyxoviridae
    • Only one serotype is known
  • Endemic throughout the world
  • A major contributor to childhood mortality,
  • 79% reduction in deaths from measles due to the global push to improve vaccine coverage 
  • A major cause of preventable blindness
  • Transmission is by droplet infection during the prodromal stage
  • Incubation period: 9 - 11 days
  • Time of exposure to appearance of rash: about 14 days

Clinical features

The essential lesion is found on the skin, mucous membranes of the nasopharynx, bronchi, intestinal tract and conjunctivae

Three stages:

  • Incubation period
  • Prodromal stage with an enanthem
  • Final stage

Incubation period:

  • Mild fever; 10 - 11 days

Prodromal stage:

  • 3-5days
  • Low grade to moderate fever
  • Dry cough
  • Coryza
  • Conjunctivitis
  • Koplik  spots
  • Photophobia

Final stage:

  • Temperature rises abruptly as the rash appears
  • Rash begins from the upper lateral part of the neck, behind the ears, along the hairline and posterior parts of the cheek then spreads to the rest of the body
  • Rash fades in the same pattern in 3 - 4 days
  • Associated lymphadenopathy

Differential diagnoses

  • Rubella
  • Roseola infantum
  • Infections from Echovirus, Coxsackie Virus and
  • Adenovirus
  • Infectious mononucleosis
  • Toxoplasmosis
  • Meningococcaemia
  • Drug rashes

Complications

  • Diarrhoea
  • Otitis media
  • Pneumonia
  • Laryngo-tracheobronchitis
  • Malnutrition
  • Encephalitis
  • flaccid paralyses
  • Seizures or Blindness
  • Subacute sclerosing panencephalitis

Investigations

  • Isolation of the virus by tissue culture
  • ELISA: first IgM and later IgG response
  • Demonstration of Warthin Finkeldy giant cells in smears of the nasal mucosa
  • Full Blood Count
  • Lumbar puncture

Treatment goals

  • Relieve symptoms
  • Hydrate adequately
  • Treat secondary bacterial infection
  • Prevent complications

Non-drug treatment

  • Humidification of the room for those with croup
  • Protection from strong light for those with
  • photophobia
  • Nutrition
  • Fluids

Drug treatment

  • If RTI is present, administer antibiotics
  • Those in final stage with fever need antipyretics
  • Some children require supplemental vitamin A
    • 100,000 IU stat for age 6 months - 1 year
    • 200,000 IU stat for age above 1year
    • Repeat on days 2 and 14 for those with ophthalmologic evidence of vitamin A deficiency
  • Specific treatment of complications:
    • Use of dexamethasone for Croup

Notable adverse drug reactions, contraindications and caution

Vitamin A may cause features of pseudotumour cerebri

  • Nausea, vomiting, drowsiness, bulging fontanelle, diplopia, papilloedema and cranial nerve palsies

Prevention

Isolation precaution from the 5th day of exposure until 5 days after appearance of the rash

Measles vaccine at 9 months

  • Vaccine may be given at 6 months for measles post-exposure, and in outbreak prophylaxis

Post-exposure prophylaxis

  • Passive immunization with immune globulin within 6 days of exposure