Measles (Rubeola)

Introduction

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

Symptoms and clinical features of measles

The essential lesion is found on the skin,
mucous membranes of the nasopharynx,
bronchi, intestinal tract & conjunctivae
Three stages:

  1. Incubation period
  2. Prodromal stage with an enanthem
  3. Final stage

Incubation period:

  • Mild fever; 10-11 days

Prodromal stage:

  • Occurs in of infection3-5days
  • 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
  • Scarlet fever
  • Rickettsial diseases
  • Kawasaki disease
  • Serum sickness
  • Drug rashes

Complications of measles

  • Diarrhoea
  • Otitis media
  • Pneumonia
  • Laryngo-tracheobronchitis
  • Malnutrition
  • Encephalitis
  • flaccid
  • Seizures
  • 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
  • Lumbar puncture: increase in CSF protein; and small increase in lymphocytes, normalvglucose level
  • Full Blood Count: low white blood cell count with relative lymphocytosis

Treatment for measles

Treatment objectives

  1. Relieve symptoms
  2. Hydrate adequately
  3. Treat secondary bacterial infection
  4. Prevent complications

Non-drug treatment

  1. Protection from strong light for those with photophobia
  2. Humidification of the room for those with croup
  3. Fluids
  4. Nutrition

Drug treatment

No specific drug is available for the treatment of measles.
Some children require supplemental vitamin A

  • Vit 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 dexamethazone for Croup

Notable adverse drug reactions

Vitamin A may cause features of
pseudotumour cerebri

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

Prevention of measles

  • Isolation precaution from the 5th day of exposure until 5days 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