Transmissible spongiform encephalopathies (TSEs), also called prion diseases, are rare diseases of the brain and nervous system. Both people and animals can get them. They are caused by a particle called a prion. When a person comes into contact with a prion, it causes the proteins which make up the brain tissue to fold the wrong way. The abnormal proteins then cause holes to develop in the brain. This leads to an appearance like a sponge. It can take years from the time of exposure until a person shows symptoms, but once the symptoms start, they progress rapidly. Sadly, these diseases are always fatal.
The symptoms of prion disease vary depending on where in the course of the disease a person is. A person may be infected for years before they begin to show symptoms such as:
Prion disease has four different causes:
There are few known risk factors for prion disease as it’s so rare and usually sporadic. Some known risk factors include:
The diagnosis of TSE requires a biopsy of the brain. The sample can be obtained either when the person is alive or during autopsy after the person has died. It must then be placed under a microscope and the characteristic sponge appearance seen, along with the abnormally folded proteins.
Other less invasive tests may be requested to diagnosis the condition, such as:
There is not a blood or urine test that diagnoses prion disease.
Unfortunately, all prion diseases cause death. The very quick worsening of symptoms can make it difficult for a family to care for a person with prion disease. The patient often ultimately ends up in a care home before they die.
There is no cure for prion disease. Any treatment options are to help with symptom control and quality of life as the disease progresses.
There is little that can be done to prevent prion disease, particularly as it is usually sporadic. Cooking meat does not kill prions. The best preventive measure is to only eat meat from farmers and ranchers that are following safety regulations for caring for their animals. There is no way to prevent sporadic cases or genetic cases. There is no screening test to determine whether a potential blood or organ donor is infected with a TSE but not yet showing symptoms.