The constellation of fever, rash, cough, and conjunctivitis isdiagnostic for measles. Koplik spots are pathognomonic butare not always present at the time the rash is most pronounced.Confirmation is by diagnostic antibody increases in acute andconvalescent sera. The rash must be differentiated from rubella, roseola, enteroviral or adenoviral infection, infectious mononucleosis, toxoplasmosis, meningococcemia, scarlet fever, rickettsial disease, Kawasaki disease, serum sickness, and drug rash.
Routine supportive care includes maintaining adequate hydration and antipyretics. High-dose vitamin A supplementation has been shown to improve the outcome of infants with measles in developing countries. The World Health Organization recommends routine administration of vitamin A for 2 days to all children with acute measles.
Otitis media is the most common complication of measles infection. Interstitial (measles) pneumonia can occur, or pneumonia may result from secondary bacterial infection with Streptococcus pneumoniae, Staphylococcus aureus, or group A streptococcus. Persons with impaired cell-mediated immunity may develop giant cell (Hecht) pneumonia, which is usually fatal. Myocarditis and mesenteric lymphadenitis are infrequent complications.
Encephalomyelitis occurs in 1 to 2 per 1000 cases and usually occurs 2 to 5 days after the onset of the rash. Early encephalitis probably is caused by direct viral infection of brain tissue, whereas later onset encephalitis is a demyelinating and probably an immunopathologic phenomenon. Subacute sclerosing panencephalitis is a late neurologic complication of slow measles infection that is characterized by progressive behavioral and intellectual deterioration and eventual death. It occurs in approximately 1 in every 1 million cases of measles, an average of 8 to 10 years after measles. There is no effective treatment.
Deaths most frequently result from bronchopneumonia orencephalitis, with much higher risk in persons with malignancy,severe malnutrition, age under 5 years, or immunocompromise (such as HIV infection). Late deaths in adolescents andadults usually result from subacute sclerosing panencephalitis. Other forms of measles encephalitis in immunocompetentpersons are associated with a mortality rate of approximately15%, with 20% to 30% of survivors having serious neurologicsequelae.