Measles (also known as rubeola) is a highly contagious infection caused by the measles virus.
The measles vaccine, first introduced in 1963, has significantly reduced the incidences of measles. However, it remains endemic in countries with low vaccination rates 1. Worldwide, it is the leading cause of vaccine-preventable mortality in children 2.
Measles infection is divided into three distinct clinical stages:
- the incubation period begins after the virus has infected an individual via the conjunctiva or respiratory mucosa
- this stage ranges from 7-21 days 1
- prodromal period:
- the incubation period is followed by nonspecific prodromal symptoms of fevers, malaise, anorexia, cough, coryza and conjunctivitis
- this phase usually lasts 2-4 days before the exanthem phase
- Koplik spots are pathognomonic small blue-white spots on the buccal mucosa and appear 1-2 days before the onset of rash 3
- after 2 to 4 days of prodromal period, the characteristic erythematous maculopapular rash appears
- the rash is non-itchy and usually begins on the face and neck and progresses down to the entire trunk and extremities, rarely affecting the palms and soles
- the rash begins to fade 3-7 days after first appearing, in the order of appearance
Measles is highly contagious. The infection is transmitted from person-to-person via aerosolized respiratory droplets produced during coughing or sneezing. Approximately 90% of susceptible individuals develop measles after exposure to the virus 4. The measles virus can cause generalized immunosuppression and hence predisposes an individual, particularly those already immunocompromised, to secondary infection such as pneumonia 5.
The role of imaging is to detect possible complications.
Chest radiography may demonstrate mixed reticular opacities, air space consolidation and lymph node enlargement in the hilum 6.
- the measles virus can affect the central nervous system and cause acute progressive encephalitis, acute post infectious encephalitis and subacute sclerosing panencephalitis 7
- in acute encephalitis associated with measles, T2 weighted image shows widely distributed, multifocal high signal lesions in both cerebral hemispheres with swelling of the cortex and bilateral, symmetrical involvement of the dorsal striatum 8
Treatment and prognosis
There are no specific treatments for measles and the treatment is essentially supportive care with antipyretics, fluid therapy, and antibiotics for secondary bacterial infections.
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- 2. Stein CE, Birmingham M, Kurian M, Duclos P, Strebel P. The global burden of measles in the year 2000--a model that uses country-specific indicators. (2003) The Journal of infectious diseases. 187 Suppl 1: S8-14. doi:10.1086/368114 - Pubmed
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- 4. Simpson RE. Infectiousness of communicable diseases in the household (measles, chickenpox, and mumps). (1952) Lancet (London, England). 2 (6734): 549-54. Pubmed
- 5. Avota E, Gassert E, Schneider-Schaulies S. Measles virus-induced immunosuppression: from effectors to mechanisms. (2010) Medical microbiology and immunology. 199 (3): 227-37. doi:10.1007/s00430-010-0152-3 - Pubmed
- 6. Gremillion DH, Crawford GE. Measles pneumonia in young adults. An analysis of 106 cases. (1981) The American journal of medicine. 71 (4): 539-42. Pubmed
- 7. Norrby E, Kristensson K. Measles virus in the brain. (1997) Brain research bulletin. 44 (3): 213-20. Pubmed
- 8. Lee KY, Cho WH, Kim SH, Kim HD, Kim IO. Acute encephalitis associated with measles: MRI features. (2003) Neuroradiology. 45 (2): 100-6. doi:10.1007/s00234-002-0884-x - Pubmed