Subacute Sclerosing Panencephalitis (As Seen on House MD)

This is part of our House MD Project series.

On episode 2 of season 1, also known as Paternity, Dan, a 16 year old gets hit in the head during a lacrosse game. He also has night terrors and double vision. After a few mis-diagnoses (including sexual abuse and multiple sclerosis) the team (or, rather, Dr. House) arrive at the correct diagnosis of subacute sclerosing panencephalitis.

Dr. House asking his team to run unethical DNA tests on episode 2 of season 1. Photo by Fox Broadcasting Company. Credit: Danny Feld/FOX.

Danger level: High

What is it?

Subacute sclerosing panencephalitis (SSPE) is a rare, progressive neurological disorder characterized by inflammation of the brain (encephalitis = brain inflammation). It’s associated with infection of the brain with the measles virus.

Who gets it?

SSPE is rare. Before the measles vaccine was used, in the 1960’s, it was more common (and even then pretty rare – 0.61 cases per million people). In the early 1990’s only 2-3 cases per year were discovered in the US.

SSPE usually happens when people are infected by the measles virus at an early age, before the age of 4, and mostly before age 2. It then affects the infected person 7-13 years after the infection.

SSPE is twice as common in males as it is in females. It also tends to happen less in people living in cities, and more in rural areas. It’s also more common in children of Hispanic origin.

What causes it?

Usually, an infection by the measles virus tends to subside and the virus goes away. In SSPE, there appears to be a persistent infection with a virus that had somehow changed. That virus stays inside the cells in the brain for several years. After 7-10 years it starts attacking the cells in the brain that previously protected it.

This causes an inflammation in the cells which eventually leads to their death.

The measles virus. In SSPE it destroys brain cells.

How does it feel?

The disease can appear anywhere between age 1 and 30, but is more common in children and adolescents, as it usually begins 7-13 years after the infection with the measles virus occurred.

The disease has 4 stages:

In stage 1 subtle changes in behavior or school performance appear – including irritability, reduced attention span, or temper outbursts. This stage may be missed since the symptoms are mild.

In stage 2, a phenomenon called myoclonus is observed (which was also seen in the House episode). This is a brief, involuntary twitch of a muscle or a group of muscles.

In stage 3 there are no more involuntary movements. Instead, other, more severe types of movement problems appear, including something called choreathetosis (dancing movements), immobility, rigidity of muscles. These result from the destruction of areas in the brain responsible for movement.

In this stage, the infected person’s consciousness also deteriorates and can lead to a coma.

In Stage 4 brain areas that control our breathing, heart rate and blood pressure are destroyed, leading to death.

How is it discovered?

If the clinical stages above are seen by a doctor this might give a clue to SSPE. Also, at least one of these findings has to exist in order to diagnose SSPE -

1. Detection of antibodies – Antibodies are molecules the body produces to fight infections. Once we are infected, they may be found in the blood. Here, we actually look for antibodies not in the blood but in the spinal fluid, which runs throughout our brain and spinal cord. This is done by taking a sample from the spine, usually by inserting a needle to the lower back.
2. Findings on EEG – EEG is a tracing of our brain’s electrical activity, much like an ECG can show the electrical activity in our heart. In SSPE, the EEG has a certain pattern that can be seen in stage 2 of the disease.
3. Brain biopsy – This used to be more common. A part of the brain was taken to examine it under the microscope and see if the virus is there. Today it’s no longer done routinely.

Example of an EEG. Photo by Der Lange.

How is it treated?

Usually no specific treatment can be offered to people with SSPE, in contrast to what was seen on the House episode. On that episode, treatment with a drug called interferon was given to the kid, which cured him. Studies made on such treatment showed that only about 30% of people treated with it improved.

What happens after treatment?

Most people, unless rarely cured by the treatment, die within 1-3 years.

SSPE can be prevented if the initial infection by the measles virus is prevented. This is done by taking the measles vaccine.