MEASLES (RUBEOLA)

MEASLES (RUBEOLA)

Current diagnosis

Viral prodrome including fever, cough, coryza, conjunctivitis, and Koplik spots.

Generalized, macular-popular rash develops 2 to 4 days after viral prodrome.

History of exposure; travel to endemic area or region affected by outbreak.

Nonvaccinated or incomplete vaccination status.

Current therapy

Vaccination is the key for prevention of disease.

Supportive Care

•   Fluid hydration, oral or IV

•   Antipyretics

•   Rest

•   Antibiotics for secondary bacterial infection

Epidemiology

Also known as rubeola, measles was declared eliminated in the United States in 2000, but has unfortunately returned in multistate outbreaks. Prior to the introduction of the national vaccination program in 1963, approximately 3 to 4 million cases of measles occurred each year, with 500,000 reported. Each year during this time, 500 deaths, 48,000 hospitalizations, and 1000 cases of permanent brain damage were attributed to measles. Cases dropped dramatically from 25,000 to 75,000 per year in the 1970s, to 3750 per year in the mid 1980s. At that time a two vaccine regimen was introduced, and by 2000 measles was considered eliminated in the United States.

However, over 2 million cases of measles occur worldwide each year. More recently a decline in vaccinations rates in the United States for various reasons has led to a resurgence of measles outbreaks when an infected individual is introduced to the population. In 2014 alone, 644 cases from 27 states were reported, which is the largest number of cases since 2000.

Risk factors

Unvaccinated status and contact with infected persons are the largest risk factors in the United States. Contact with infected individuals can occur in a multitude of locations. Careful social and travel history must be obtained for suspected cases. Travel to an international location where measles is still endemic or there is a local outbreak is an essential factor in making the diagnosis in the United States.

Pathophysiology

A member of the genus Morbillivirus in the family Paramyxoviridae, measles is considered one of the most infectious viral pathogens. The disease is contracted by contact with respiratory droplets of an infected individual. Up to 90% of susceptible individuals develop measles after exposure. An infected individual is considered contagious 4 days prior to the appearance of a rash and 4 days after it is gone. The virus itself remains viable both on surfaces and in the air for 2 hours after a cough or sneeze. Case reports demonstrate that aerosol transmission across large spaces is possible, such as a gymnasium. Average incubation period of the disease is 10 to 14 days.

Prevention

The best way to prevent contracting measles is through individual and herd immunity with vaccination. The MMR (measles, mumps, and rubella) vaccine series is recommended for all individuals born after 1957, with few exceptions. Exceptions include individuals with primary or acquired immunodeficiency, individuals with blood dyscrasias, those with a family history of a first degree relative with hereditary or congenital immunodeficiency, individuals receiving systemic immunosuppressive therapy, and pregnant women. The MMR vaccine is given in children over 1 year of age, and adults in two doses separated by at least 28 days. One dose of vaccine has been shown to provided 95% immunity, and up to 99% immunity after two doses.

The majority of people who have recently contracted measles in the United States have been unvaccinated. Isolation of infected individuals is also recommended, and all suspected cases must be reported to local health departments. There are currently no clear guidelines on the isolation of measles patients. The majority of cases do not need to be hospitalized, but often visit their primary care physician for diagnosis. Masks should be placed on the patient, family, and staff. All health care workers should have documented immunity, and if not, it is recommended they do not treat suspected cases. Measles can remain airborne for up to 2 hours, therefore if possible, keep rooms closed after use, and exits separate for infected individuals.

Postexposure prophylaxis for those exposed to measles is an option for prevention of disease. MMR vaccine may alter the clinical course and offer protection if it is given within 72 hours of initial exposure.

Immune globulin (IGIM) can be considered to reduce the risk for infection and complications if given within 6 days of exposure, and is usually reserved for those immunocompromised or who can otherwise not receive the vaccine.

Clinical Manifestations

Symptoms of measles present in two stages. The first stage starts with a viral prodrome of coryza, cough, fever (> 38.3 ° C), Koplik spots, conjunctivitis and photophobia. The second stage consists of a generalized, macular popular, erythematous exanthem. Described as 1 to 3 mm white elevations on an erythematous base, Koplik spots can also be seen on the palate and labial mucosa. Koplik spots develop in the buccal mucosa a few days prior to exanthem, and fade and slough during exanthem progression. The exanthem typically begins behind the ears and along the hairline, then proceeds downward to the trunk and extremities. Often the exanthem become confluent, with possible petechiae, and eventually darkens to a brown color. The rash lasts for a total of 6 to 7 days, eventually fading with a fine desquamation.

Diagnosis

Diagnosis is based primarily on clinical presentation, vaccination, travel, and exposure history. Blood counts may show leukopenia, T cell cytopenia, and thrombocytopenia. Histologic evaluation may show giant cells with inclusions in conjunctival, nasopharyngeal, or buccal epithelial cells.

Confirmation can be made by enzyme-linked immunosorbent assay (ELISA) detection of measles specific antibodies. Immunoglobulin M (IgM) is detectable three days after the appearance of the rash, and for up to 30 days after. Immunoglobulin G (IgG) peaks around 14 days after rash. Viral cultures can be obtained from blood, respiratory secretions, conjunctival swabs, or urine. If suspected, obtain specimens for confirmation and genotyping. Local health departments will assist in choosing and submitting specimens for testing.

Differential Diagnosis

In the early stages of disease, measles can appear similar to any viral upper respiratory infection. The viral prodrome is similar to that of the rhinovirus, parainfluenza, adenovirus, respiratory syncytial virus, and influenza. Koplik spots are pathognomonic, but often subtle and overlooked. When the viral exanthema appears, it can be confused with roseola, rubella, scarlet fever, drug eruption, parvovirus B19 infection, and Kawasaki disease.

Therapy

There is currently no specific therapy for measles. Supportive care including fluids, antipyretics, and treatment of secondary bacterial infections are the mainstay of therapy. Avoidance of light for those with photosensitivity is recommended. There is a role for vitamin A1 in developing countries, but it is not routinely recommended in the United States. Ribavirin (Rebetol)1 has been shown to be effective in vitro; limited case reports are available.

Monitoring

Follow up visits for confirmed measles are not required unless the patient develops complications. Dehydration from diarrhea, ear pain from otitis media, and difficulty breathing, or prolonged and productive cough are reasons to seek further care. Most cases are self- limiting, and resolve at home with supportive care.

If a patient requires hospitalization, respiratory isolation should be initiated. Rooms should be under negative pressure ventilation and masks (N95) used at all time. Only health care workers with documented immunity should care for these patients. Providers should work closely with their local health departments to determine length of monitoring for contacts, and isolation for confirmed cases.

Complications

Measles can cause many complications, some self-limiting, and others life threatening. Common complications include otitis media (3% to 9%), bronchitis, or bronchopneumonia (1% to 6%). 1 in 1000 infections is complicated by encephalitis. A rare, often fatal neurologic degenerative disease, known as subacute sclerosing panencephalitis can develop 7 to 10 years after acute measles. A higher risk is seen in individuals who are less than 2 years of age when measles is contracted, but averages 4 to 11 per 100,000 cases. Secondary bacterial infections are common because of immunosuppression by the virus, and are responsible for most measles deaths. Overall the risk for death is higher in infants, young children, and adults. Worldwide the death rate can be as high as 25%, particularly in areas where malnutrition is prevalent.

References

1.     Centers for Disease Control and Prevention. Prevention of measles, rubella, congenital rubella syndrome, and mumps, 2013: summary recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep. 2013;62:1–34.

2.    Cherry J.D. Measles virus. In: Feigin R.D., Cherry J.D., Demmler- Harrison G.J., et al., eds. Textbook of Pediatric Infectious Diseases. ed 6th Philadelphia: Elsevier; 2009:2427.

3.     Griffin D.E., Bellini W.J. Measles virus. In: Fields B.N., Knipe D.M., Howley P.M., eds. Fields’ Virology. Philadelphia: Lippincott-Raven; 1996:1267.

4.    Helmecke M.R., Elmendorf S.L., Kent D.L., et al. Measles investigation: a moving target. Am J Infect Control. 2014;42:911–915.

5.     Infectious Disease Society of America: U.S. Multi-state measles outbreak. December 2014–January 2015. Available at: http://www.idsociety.org/Breaking_News_and_Alerts/CDC_H state_Measles_Outbreak,_December_2014- January_2015_(content)/ [accessed 07.05.15].

6.      McLean H.Q., Fiebelkorn A.P., Temte J.L., Wallace G.S. Centers for Disease Control and Prevention. Prevention of measles, rubella, congenital rubella syndrome, and mumps, 2013. Summary recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep. 2013;62:1–34.

7.    Measles cases and outbreaks. Available at: http://www.cdc.gov/measles/cases-outbreaks.html [accessed 01.02.15].

8.    Treating measles in children. Geneva: World Health Organization; 2004 updated. http://www.measlesinitiative.org/mi- files/Reports/Treatment/Treating%20Measles%20in%20Childre [accessed 20.01.15].

1  Not FDA approved for this  indication.

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