Creutzfeldt-Jakob disease (CJD) is a rare and fatal condition that affects the brain. It causes brain damage that worsens over time.
Symptoms of CJD include:
- loss of memory
- loss of balance and co-ordination
- slurred speech
- visual problems and blindness
- abnormal jerking movements
- progressive deterioration and immobility
Most people with CJD will die within a year of the symptoms starting, usually from infection. This is because the immobility caused by CJD can make patients vulnerable to infection.
Read more about the symptoms of Creutzfeldt-Jakob disease.
What causes CJD?
CJD is a rare disorder that appears to be caused by an abnormal protein called a prion. Prions accumulate at high levels in the brain and cause irreversible damage to nerve cells, causing the neurological symptoms described above.
Prions are infectious particles made of abnormally folded protein. They are very different in their behaviour to conventional viruses and bacteria, and are not destroyed by the extremes of heat and radiation used to kill bacteria and viruses.
Antibiotic and antiviral medicines have no effect on prions, and there is no effective treatment for CJD (see below).
Read more about the causes of Creutzfeldt-Jakob disease.
Treating CJD
There is currently no cure for CJD so treatment involves helping to relieve symptoms and making a patient feel as comfortable as possible.
This can include using medication such as antidepressants to improve mood and painkillers to relieve pain. Assistance with feeding may also be required.
Read more about the treatment of Creutzfeldt-Jakob disease.
Types of CJD
There are four main types of CJD, which are described below.
Sporadic CJD
Sporadic CJD is the most common type of CJD.
For reasons that are still unclear it appears that in cases of sporadic CJD a normal protein undergoes an abnormal change (mutation) and turns into a prion.
Most cases of sporadic CJD occur in older adults aged between 45 and 75 years, with the average age being around 60-65 years.
Despite being the most common type of CJD, sporadic CJD is still very rare, affecting only one in every million people in any given year in the UK.
There were 74 deaths due to sporadic CJD in the UK during 2011.
Variant CJD
Variant CJD is caused by eating meat from a cow that has been infected with a similar prion disease called bovine spongiform encephalopathy (BSE, also known as mad cow disease).
Since the link between variant CJD and BSE was discovered in 1996 there have been strict controls, that have proved extremely effective, to prevent meat from infected cattle from entering the food chain.
However, the average time it takes for the symptoms of variant CJD to occur after initial infection (the incubation period) is still unclear. The incubation period could be very long in some people. So people who were exposed to infected meat before the food controls were introduced continue to develop variant CJD.
There were five deaths due to variant CJD in the UK during 2011.
Familial CJD
Familial CJD is a rare genetic condition where the genes a person inherits from one of their parents cause a protein to mutate into a prion in later life, triggering the onset of symptoms of CJD.
Most cases of familial CJD first develop in people who are in their early 50s.
There were nine deaths due to familial CJD in the UK during 2011.
Iatrogenic CJD
Iatrogenic CJD is where the infection is spread from someone with CJD through medical or surgical treatment.
For example, in the past a common cause of iatrogenic CJD was that a person was given growth hormone treatment with hormones extracted from somebody with CJD. Synthetic versions of growth hormones are now used so this is no longer a risk.
Cases of iatrogenic CJD can also occur if instruments used during brain or nerve surgery are not properly cleaned between each surgical procedure.
Due to increased awareness of these risks, iatrogenic CJD is now very rare. There were only three deaths due to iatrogenic CJD in the UK during 2011.
