Measles (Rubeola)

Measles is a very contagious viral illness caused by an RNA virus. It is found world wide and has a very distinct clinical picture. 

Clinical Course

  1. After an incubation period of 8-12 days, the initial symptom is a fever, sometimes to 40C. Average time from exposure to rash is 14 days. 
  2. This is followed by the development of the three C’s, cough, conjunctivitis, and coryza. 
  3. Koplik spots, white spots on a red base on the buccal mucosa, will develop during this period prior to the development of the rash.
  4. The rash begins on the head and moves caudally. It is a maculopapular rash that is often confluent and not pruritic. It may last for up to a week and fades in order of appearance. It may be hemorrhagic.
  5. Variations and milder forms may occur if there is protective maternal antibody present or the child has recently received immunoglobulin. Individuals who have been immunized and have waning immunity, may have a milder disease. 
Complications
  1. Otitis and pneumonias that are of viral or secondary bacterial etiology.
  2. Croup syndromes
  3. Gastroenteritis including appendicitis like symptoms secondary to obscuring of the appendiceal lumen by proliferating lymphoid tissue.
  4. encephalitis occurs in 1/1000 cases
  5. SSPE-Subacute sclerosing panencephalitis. This is a rare degenerative CNS disease that may occur years after the infection and presents with seizures, coma, and death.
  6. Myocarditis
Differential Diagnosis
  1. Usually easily distinguishable by the distinct clinical course but may be confused with enteroviral diseases, rubella, Streptococcal infections, drug reactions, and ricketsial diseases.
Diagnosis
  1. Clinical picture
  2. IgM titers or increased convalescent titers 2-3 weeks after the illness
  3. Can culture secretions but rarely done because isolation of virus is technically difficult
Epidemiology
  1. Most cases are in the unimmunized or infants too young to have received the vaccine. 
  2. Certain religious groups that are opposed to immunizations have had outbreaks.
  3. Because of possible waning immunity, a second dose was added in 1989
  4. Mothers that are immune passively transmit antibodies transplacentally. This will last 4-6 months. Immunized mother may transfer less immunity than those who have had the natural disease.
  5. Transmission is by respiratory droplets and the transmission can occur 2 days prior to symptoms and 4 days after the rash appears. The patient should be in respiratory isolation.
  6. Immunity
    1. born before 1957
    2. physician documented disease
    3. immunized
    4. Laboratory evidence of immunity
  7. Individuals who are less than 12 months old, pregnant, or immunocompromised should receive immunoglobulins following exposure. Should be given within 6 days of exposure. If a child receives IG, can be vaccinated 6 months later. 
Vaccine
  1. Given to infants at one year of age and second dose at 4-6 years. 
  2. Allergy to eggs is not a contraindication to vaccinating
  3. HIV positive individuals may be given MMR but severely immunocompromised with low CD4+T lymphocytes, should not be immunized.
  4. May give simultaneously with the varicella vaccine
  5. May cause anergy to PPD that will last 1 month. May be given at the same time of PPD
  6. Contraindicated in patients on immunosuppression, leukemics, and individuals with untreated active TB.
  7. If given within 72 hours after exposure, may protect against the disease.
  8. During an outbreak of measles, vaccine may be given as early as 6 months of age.
  9. Adverse reactions
    1. fever 7-12 days after vaccination
    2. rarely allergic or anaphylactic reactions
Treatment
  1. Supportive measures
  2. Antivirals have not been effective
  3. Patients in third world countries where Vitamin A deficiency is a problem, should receive Vitamin A.
References
  1. 1997 Red Book
  2. Adam HM and Fennelly GJ. Updates on Measles Vaccine. Pediatrics in Review. 1998 19:323a.
  3. Fennelly GJ and Adam HM. Measles Vaccine. Pediatrics in Review. 1998; 19:178-179.
  4. Gold, Eli. Almost Extinct Diseases: Measles, Mumps, Rubella, and Pertussis. Pediatrics in Review. April 1996.
  5. Resnick SD. New Aspects of Exanthematous Diseases of Childhood. Dermatologic Clinics. 1997; 15(2):257-266.
  6. Zendel, Joseph A. An Infant Who Has Fever and Rash. Pediatrics in Review. 2000; 21:105-107.
  7. Mulholland E. Measles in the United States, 2006 NEJM Aug 3, 2006
  8. Parker A. et al. Implications of a 2005 Mesles Outbreak in Indiana for Sustained Elimination of Measles in the United States. NEJM Aug 3, 2006
  9. MMWR 2008 San Diego Outbreak
  10. Measles.  Pediatrics in Review September 2007