Measles is a highly contagious viral illness caused by the measles virus (Paramyxoviridae family).

  • Characterized by fever, malaise, cough, coryza, and conjunctivitis, followed by exanthem
  • On exposure, 90% of susceptible individual will develop measles.
  • Period of contagiousness: 5 days before the appearance of the rash to 4 days afterward
  • Leading cause of mortality especially among children ≤5 years of age

History and examination

  • Children and non-immunized adults
  • Risk factors: Unvaccinated individuals, malnutrition, vitamin A deficiency, immunosuppression
  • Measles present with classic measles, modified measles, atypical measles, measles with neurological syndrome, severe measles, and with other complication.

Symptoms

  • Prodromal phase: High fever(peaking 2–3 days after appearance of rash), malaise, cough, coryza, non-purulent conjunctivitis, pharyngitis
  • Rash phase: Develop 2–4 days after onset of fever; Consist of an erythematous, maculopapular, blanching rash, which classically begins on the face and spreads cephalocaudally and centrifugally to involve the neck, upper trunk, lower trunk, and extremities.
measles rash

Signs

  • Koplik’s spots: 48 hours prior to onset of the exanthem, patients may develop an Koplik spots; these are 1–3 mm whitish, grayish, or bluish elevations with an erythematous base, typically seen on the buccal mucosa opposite the molar teeth.
  • Lymphadenopathy

Differential diagnosis (D/D) & Complication

D/D

  • Scarlet fever (Sore throat, sandpaper-like rash, strawberry tongue)
  • Drug rash
  • Kawasaki disease
  • Infectious mononucleosis
  • Meningococcemia

Complications

  • Pneumonia
  • Otitis media
  • Encephalitis
  • Acute disseminated encephalomyelitis (ADEM)
  • Subacute sclerosing panencephalitis
  • Keratitis, pericarditis, myocarditis

Note: Measles is associated with a transient but profound immunosuppression, resulting in an increased susceptibility to opportunistic infection.

Investigation

  • Serology: Measles-specific IgM antibody
  • Reverse transcriptase PCR (RT-PCR) for measles virus RNA
  • CBC: Thrombocytopenia , leukopenia
  • Chest x-ray: Interstitial pneumonitis

Admission criteria

  • Severe complications (e.g., pneumonia, encephalitis)
  • Immunocompromised patients
  • Malnourished children

Management

Medical:

  • Supportive care (hydration, antipyretics, analgesics) as there is not specific anti-viral therapy
  • Vitamin A supplementation
  • Antibiotics for secondary bacterial infections

Rx:

  • Paracetamol/Flexon for fever and pain
  • Oral rehydration solution for dehydration
  • Oral Vitamin A: Give once daily for 2 days

Dose:

  1. 50,000 IU (< 6 months of age)
    1. 100,000 IU (6-11 months of age)
    1. 200,000 IU (>12 months of age)

Note: Measles is notifiable disease under Measles-Rubella Surveillance.

Advices

  • Isolation until at least 5 days after rash onset
  • Vaccination of all eligible children
  • Measles, mumps, and rubella vaccination according to the schedule and catch-up vaccination of those children who have missed the doses.

Referral

  • Suspected complications or severe cases
  • Immunocompromised patients

Follow up

  • 1-2 weeks after recovery to monitor for complications
  • Ensure up-to-date vaccinations

Additional points

  • Pathogenesis
    • Two membrane envelope proteins are important for pathogenesis.
      • F (fusion) protein: Responsible for fusion of virus and host cell membranes, viral penetration, and hemolysis.
      • H (hemagglutinin) protein:  Responsible for binding of virus to receptors on host cells.
    • Highly infectious, and is transmitted by aerosols generated during coughing or by direct contact with contaminated respiratory secretions
    • Dissemination of measles virus due to viremia, with associated infection of endothelial, epithelial, monocyte, and macrophage cells, may explain the variety of clinical manifestations and complications that can occur with measles virus infection.
    • Incubation period: 2 weeks then, disease starts with a prodromal phase of fever, cough, and coryza.
    • Koplik Spots: Patients may develop an enanthem, 48 hours prior to onset of exanthema, characterized by Koplik spots; these are 1–3 mm whitish, grayish, or bluish elevations with an erythematous base, typically seen on the buccal mucosa opposite the molar teeth.
    • Rash:
      • Arises approximately 2–4 days after onset of fever
      • Erythematous, maculopapular, blanching rash, which classically begins on the face and spreads cephalocaudally and centrifugally to involve the neck, upper trunk, lower trunk, and extremities.
      • Associated with lymphadenopathy, high fever (peaking 2–3 days after appearance of rash), pronounced respiratory signs including pharyngitis, and nonpurulent conjunctivitis.
  • Measles is preventable with vaccination (MMR vaccine)
  • Immunize all eligible children according to national guidelines

References:

  1. World Health Organization. Measles. https://www.who.int/news-room/fact-sheets/detail/measles
  2. Moss WJ. Measles. Lancet. 2017; 390(10111): 2490–2502.
  3. Perry RT, Halsey NA. The clinical significance of measles: a review. J Infect Dis. 2004; 189(Suppl 1): S4–S16.