Measles

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[edit] Measles

Measles is a highly contagious viral infection and is one of the six common childhood rashes. It affects those who are susceptible. In the past this was responsible for the high mortality of the indigenous people of North America when the white man came from Europe bringing along this viral illness. Now there is an effective vaccination program throughout most of the developed countries that has saved millions of lives. It is hard to believe that worldwide there are still about 35 million people infected resulting in 750,000 to 850,000 deaths annually affecting mostly children. Because of the vaccination program there are only about 200 cases of measles every year in the US.

Signs and Symptoms:

There is a 7 to 14 day incubation time with a runny nose, a conjunctivitis and a hacking cough. One of the earliest signs for the physician to see is the development of Koplik's spotsinside the buccal mucosa opposite the first or second upper molars or on the palate. These spots resemble grains of sand, which are surrounded by a red spot. They are from a local viral infection. Typically one or two days after the Koplik's spots and at about 4 to 5 days from the beginning of the incubation period the typical skin rash appears in an orderly fashion. First there is a an accumulation of red blotches in the face in front and below the ears and migrating via the sides of the neck within 1 to 2 days to the trunk and to the extremities. The rash includes the palms of the hands and the soles of the feet. When this occurs, the rash begins to fade from the face. There are a lot of variations between persons and family members in termsof the severuty of the viral illness. In more severe presentations there can be bleeding into the skin. This type of rash can also occur in rare cases following measle vaccination and is called Henoch-Schonlein purpura. At the height of the rash the fever also reaches high values of 40°C and stays there for 3 to 4 days. The sick child or person has also swelling around the eyes, conjunctivitis and photophobia (sensitivity to light). People who are immunocompromised are at a high risk of developing severe pneumonia. As the pathologist will see this imagein the microscope with a giant cell formation, this condition is also called a progressive giant cell pneumonia. These persons are also susceptible to encephalitis (an inflammatory condition of the brain with socalled measle virus inclusion bodies)and would be at a higher risk for getting seizures at the height of their infection. However, in persons with a normal immune system there also is a smaller risk of developing encephalitis as a complication (about 1 in 1000 cases of measles).

Bacterial superinfection can occurs with pneumonia, otitis media and other infections. When the patient is in the recovery phase, typically 14 days after the measles rash has disappeared, a second fleeting purpuric rash may appear. Due to a temporary suppression of the platelet count in the blood (thrombocytopenia)from the measles virus infection there are pin size blood spots that leaked into the skin from skin capillaries and this is medically called acute thrombocytopenic purpura. It tends to be self limiting. The death rate from mealses in people with a normal immune system is 1 in 5,000 to 10,000 cases.

Diagnosis:

The diagnosis is usually done on clinical grounds, by the sequence of symptoms, the occurrence of acute conjunctivitis, Koplik spots, the hacking, dry cough and the typical measles rash. However, in difficult cases the cxoctor may decide to use blood tests with an acute and recovery serum to verify the diagnosis at the end (hemagglutination inhibition test or ELISA test).

Treatment:

Treatment is symptomatic with cool baths, acetaminophen to lower the temperature and supportive measures. If bacterial superinfection of the ears, sinuses or lungs occurs, it is treated with antibiotics. Isolation to avoid infection of non immunized persons is important as it is highly contageous.

Prevention:

Despite discussions about the side-effects of measles/mumps/rubella vaccination the risk associated with the MMR program is so much smaller than the risk of "going natural". Without the vaccination protocol in the US and other industrialized nations the death toll would be as high as in the developing countries that have no formal vaccination program in place.

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References: 1. David Heymann, MD, editor: Control of Communicable Diseases Manual, American Public Health Association, 2004. 2. The Merck Manual,18th edition. Merck&Co., 2006.