​What is CJD?

CJD is a very rare and serious brain disease. It causes damage to the brain over time, which results in the death of brain cells (neurons) and causes the brain tissue to become spongy. This can lead to dementia and death. It is one of a group of diseases known as the transmissible spongiform encephalopathies (TSEs) or prion diseases. In Australia, when counting TSEs notified in humans, we usually use the label CJD.

What causes CJD?

CJD is caused by infectious brain proteins called prions. The build-up of these infectious prions damages the brain cells and causes disorders of the brain, spinal cord, and nerves.

There are different types of CJD:

Classical CJD occurs in Australia and there are three types:

• Sporadic CJD: This type of CJD occurs by chance (90% of classical cases are sporadic).
  
• Familial or genetic CJD: This type of CJD is inherited. This includes Gerstmann-Sträussler-Scheinker syndrome (GSS) and fatal familial insomnia (FFI).
• Medically acquired CJD: also known as iatrogenic CJD. This type of CJD is very rare and it occurs when the disease is spread accidentally during a medical procedure. The last known case of medically acquired CJD in Australia was reported in 2000. For more information on medically acquired CJD, refer to How is CJD spread and who is at risk.

Variant CJD is linked to the consumption of meat products from cattle infected with bovine spongiform encephalopathy (BSE, or mad cow disease). It emerged in the United Kingdom in the 1990s. To date, Australia has not identified any human cases of variant CJD or mad cow disease in cattle.

What are the symptoms of CJD?

People with CJD can have the following neurological symptoms:

• behavioural or personality changes
• vision problems
• muscle weakness
• difficulty walking
• loss of balance and coordination.

Later in the disease, symptoms include:

• dementia (memory loss)
• confusion
• difficulty speaking
• hallucinations (seeing or hearing things that are not there)
• blindness.

The disease is fatal, and death usually occurs weeks to months after symptoms start. The average age when symptoms start is about 65 years.

People with variant CJD have similar symptoms to classical CJD, but:

• tend to be younger
• have a slower rate of deterioration
  
• tend to have more psychiatric symptoms or personality changes.

How is CJD spread and who is at risk?

SporadicCJD is due to build up of abnormal prion proteins in a person's brain. These types of CJD have not been caught from other people. Each year, about one in every million Australians develops sporadic CJD by chance. Most have no risk factors for the disease.

FamilialCJD occurs when the genetic mutations are inherited. This is where abnormal genes are carried from one generation of a family to the next.

Medically acquiredCJD occurs with the spread of any type of CJD from one infected person to another during a medical procedure. These can include brain, spinal cord, nervous tissue, and eye surgeries. It is very rare. Spread can occur from using:

• contaminated equipment that has not been processed properly (the last reported case in Australia was in 2000)
  
• contaminated blood transfusions, tissues, or human pituitary hormones.

Contaminated products that have previously spread CJD include:

• human pituitary extract hormone for infertility or short stature (five cases in Australia – most recently in 1991)
• dura mater grafts used in brain surgery to repair damage to the membrane covering the brain (five cases in Australia)
• corneal grafts (three cases worldwide and none in Australia).
  

The risk of medically acquired CJD has been reduced in Australia by ceasing the use of human tissue in growth hormone treatments and dura mater grafts, and by establishing stronger guidelines for organ donation and for sterilising neurosurgical equipment.

Variant CJD is spread to humans after eating contaminated meat and meat products from cattle with mad cow disease. This has never occurred in Australia.

How is CJD prevented?

There is no way to prevent sporadic CJD.

Medically acquired CJD is prevented with specific infection control precautions for patients thought to be at risk of CJD. Products or instruments identified as potentially contaminated with prions from infected patients are removed from use.

How is CJD diagnosed?

CJD is difficult to diagnose. A definite diagnosis of CJD requires special tests of the brain tissue obtained from a biopsy. This almost always occurs after the patient has died.

There are other specialised tests that can help to make a diagnosis, but they do not confirm the diagnosis. This can include:

• magnetic resonance imaging (MRI)
• electroencephalogram (EEG)
• lumbar puncture.

To confirm the diagnosis after death, an autopsy is usually recommended.

There is no screening test for CJD to find the disease before symptoms occur.

How is CJD treated?

CJD is a fatal disease and there is no cure for CJD. Treatment aims to relieve some symptoms, such as pain or jerky movements.

If you or your loved one has symptoms of CJD or you are concerned about CJD, speak to your doctor, or in an emergency, call Triple Zero (000). For free 24-hour health advice, you can call healthdirect on 1800 022 222.

What is the public health response to CJD?

CJD is a notifiable condition in NSW. Hospitals and laboratories are required to notify patients with CJD to the local public health unit.

The Australian National Creutzfeldt-Jakob Disease Registry coordinates surveillance and testing for CJD cases in Australia. The Registry works with NSW Health and local public health units to provide specialist advice and identify if cases have had high-risk procedures.

Further information

• CJD Support Group Network Australia suport for people affected by CJD and other prion diseases.
• Australian National Creutzfeldt-Jakob Disease Registry.