Subacute sclerosing panencephalitis, a progressive and usually fatal brain disorder, is a rare complication of measles that appears months or years later and causes mental deterioration, muscle jerks, and seizures.
Subacute sclerosing panencephalitis is characterized by a persistent measles virus infection in the brain tissue.
The first symptoms are usually poor school performance, forgetfulness, temper outbursts, distractibility, sleeplessness, and hallucinations.
The diagnosis is based on symptoms and established medical criteria.
There is no treatment for subacute sclerosing panencephalitis.
This disorder is usually fatal.
Subacute sclerosing panencephalitis (SSPE) is thought to be a long-term measles virus infection. Measles virus sometimes enters the brain during a measles infection and may cause immediate symptoms of a brain infection (encephalitis), or the virus may remain in the brain for a long time without causing problems.
SSPE occurs usually 7 to 10 years after a measles infection in about 4 to 11 people per 100,000 people who had a wild-type measles infection. "Wild-type" measles infections are caused by naturally occurring strains that are highly contagious. In the past, SSPE occurred in about 1 person per million people who received the measles vaccine, but doctors now think the people who developed SSPE after vaccination likely had a mild, undiagnosed case of measles before they were vaccinated and that the measles infection, and not the vaccine, caused the SSPE.
SSPE is very rare in the United States and Western Europe because of widespread measles vaccination. The risk of SSPE is much higher in children under 12 months of age and in children under 5 years of age. This risk to children in these age groups is of particular concern given the increasing outbreaks of measles among unvaccinated people.
Males are affected more often than females.
Symptoms of SSPE
The first symptoms of SSPE may be poor performance in schoolwork, forgetfulness, temper outbursts, distractibility, sleeplessness, and hallucinations. Sudden muscular jerks of the arms, head, or body may occur. Eventually, seizures may occur, together with abnormal, uncontrollable muscle movements. Intellect and speech continue to deteriorate.
Later, the muscles become increasingly rigid, and swallowing may become difficult. The swallowing difficulty sometimes causes people to choke on their saliva, resulting in pneumonia. People may become blind.
In the final phases, the body temperature may rise, and the blood pressure and pulse become abnormal. People may further deteriorate to coma and die.
Diagnosis of SSPE
Established criteria
Tests on cerebrospinal fluid or blood
Imaging tests
A doctor suspects SSPE in young people who have mental deterioration and muscle jerks.
Doctors use an established set of criteria to help them diagnose SSPE. Before they can apply the criteria, doctors first test and examine samples of cerebrospinal fluid or blood and perform several imaging tests. Doctors diagnose SSPE in people who have signs of the disease, high levels of antibody to the measles virus in their blood or spinal fluid, and an abnormal electroencephalogram (EEG), magnetic resonance imaging (MRI) test, or computed tomography (CT) scan that shows brain abnormalities.
A biopsy of the brain may need to be done if the tests cannot reveal a cause.
Treatment of SSPE
Antiseizure medications
Nothing can be done to stop the progression of SSPE.
Antiseizure medications may be taken to control or reduce seizures. Antiviral medications are sometimes given but usually are not helpful.
Prognosis for SSPE
SSPE is nearly always fatal within 1 to 3 years.
Although the cause of death is usually pneumonia, the pneumonia results from the extreme weakness and abnormal muscle control caused by the disease.
