Creutzfeldt-Jakob Disease

Written by Rachel Reiff Ellis, Stephanie Booth
Medically Reviewed by Shruthi N, MD on June 01, 2025
6 min read

Creutzfeldt-Jakob disease (CJD) is a rare brain disorder. It makes your brain tissue look sponge-like when looked at under a microscope.

"Unfortunately, CJD is a devastating disease and one of the fastest progressing neurodegenerative diseases," says S. Ahmad Sajjadi, MD, PhD, associate professor of neurology at the University of California, Irvine. "Timely diagnosis is extremely important to allow for appropriate planning and care." 

Creutzfeldt-Jakob disease vs. mad cow

Some people confuse Creutzfeldt-Jakob disease with "mad cow disease." They're not the same.

Mad cow disease. Also known as bovine spongiform encephalopathy (BSE), it's a brain disorder that only happens in cows. It damages their nervous system and causes them to lose their balance or act violently. Cows can get it if they eat feed made from the parts of other infected cows.

There's no cure for mad cow disease. Cattle that have it get worse very quickly.

Variant CJD (vCJD) is a type of BSE that humans can get. Experts believe this can happen if you eat meat from a cow infected with mad cow disease. But vCJD is very rare, especially in the U.S. Most cases of Creutzfeldt-Jakob disease don't happen this way.

There are three types of classic CJD. Each has a different cause:

Sporadic Creutzfeldt-Jakob disease

This is the most common type. It's caused by a once-healthy protein in your body that has changed shape. Known as a prion, this “misfolded” protein can infect your brain and get other proteins to change their shape, too. This destroys your brain cells. 

Familial Creutzfeldt-Jakob disease

This happens if you inherit a mutated gene from a parent. Only 10%-15% of CJD cases each year are familial.

Acquired Creutzfeldt-Jakob disease

The rarest form, this happens if you come into contact with a medical instrument (like a scalpel), organ (through a transplant), or growth hormone that's infected with CJD. It makes up less than 1% of classic CJD cases.

CJD symptoms start and worsen very quickly. People with this condition often show signs of dementia, including:

  • Confusion
  • Trouble walking
  • Jerky muscle movements or twitching
  • Personality changes
  • Trouble with memory and judgment
  • Vision problems

You could also have trouble sleeping or feel depressed. In later stages of the disease, it's common to lose the ability to speak or move. People with Creutzfeldt-Jakob disease may also get pneumonia or other infections, or slip into a coma (lose consciousness).

Creutzfeldt-Jakob disease and dementia

Dementia isn't a specific disease. It's a group of symptoms that affect your thinking and memory. Alzheimer's is the most common reason for dementia. But many other conditions can cause it, too. Creutzfeldt-Jakob disease is one of them.

The symptoms of CJD and Alzheimer's look a lot alike. But if you have CJD, your symptoms tend to get worse faster — within weeks to months after they first start.

There is no single test for CJD. Doctors diagnose it from your symptoms. One sign of the disease is the speed with which it worsens.

A few tests doctors can use to check for Creutzfeldt-Jakob disease include:

MRI. This brain scan puts together detailed images. Doctors use these images to see changes in the brain over time.

Electroencephalogram (EEG). Surface electrodes (small devices that are placed on your head) measure the electrical activity in your brain.

Lumbar puncture (spinal tap). Doctors use a long, very thin needle to draw some of the fluid out of your spinal column. They can then test it for certain proteins.

The only way to know for sure someone has CJD is by taking a sample (called a biopsy) of their brain tissue.

Doctors don't usually biopsy brain tissue because it's risky, both for the patient and the doctor. It's hard to know which tissue in the brain is infected, so doing a biopsy may not be helpful. And it puts the doctor at risk of getting infected, too.

Since a positive diagnosis doesn't help someone with CJD, doctors often confirm cases only after someone dies of it.

Creutzfeldt-Jakob disease symptoms become more intense over time.

Early stage of Creutzfeldt-Jakob disease

At first, you might notice things such as:

  • Slurred speech
  • Feeling dizzy
  • Feeling numb or like parts of your body are "asleep"
  • Hallucinations (seeing things that aren't there)
  • Anxiety
  • Feeling cranky for no reason
  • Not wanting to spend time with people you love
  • Insomnia (trouble falling or staying asleep)

Advanced stage of Creutzfeldt-Jakob disease

As time goes on, CJD symptoms become more intense. They often include:

  • Loss of bladder or bowel control (trouble holding your pee or poop)
  • Finding it hard to swallow or speak
  • Feeling angry or hostile
  • Severe memory loss
  • Paranoia (feeling like others are trying to harm you)
  • Having feelings that don't "fit" the current situation

Final stage of Creutzfeldt-Jakob disease

In this phase, people are usually not able to get out of bed, talk to others, or understand where they are. End-of-life care can be very helpful.

Creutzfeldt-Jakob disease life expectancy

About 70% of people who with Creutzfeldt-Jakob disease live less than a year after learning they have it. 

Learning about this outcome may feel very scary. It's also common to feel a range of other emotions such as anger, sadness, worry, or denial. You don't need to manage this diagnosis on your own. Ask your doctor to help connect you to support.

There's no cure for CJD. Researchers have tested several drugs, but none have been able to slow or stop the disease.

For now, "treatment options are limited to modestly effective symptomatic treatments," says Sajjadi.

For instance, your doctor can prescribe pain medicine. Muscle relaxers or anti-seizure drugs can help with stiffness. It's common to need full-time care once the disease is in its late stage.

Researchers keep looking for more ways to prevent CJD or stop it from getting worse. In the future, that could include antibodies that target the prion protein or ways to silence the genes that cause it, Sajjadi says.

You could ask your doctor if there's a clinical trial you can join. These studies test new treatments that aren't yet sold to the general public.

Creutzfeldt-Jakob disease is a rare brain disorder that swiftly causes dementia and loss of life. It happens when a once-healthy protein in your body changes shape and can no longer function, then infects other healthy proteins around it. There is no cure yet for CJD. Instead, your doctor will manage your symptoms and help keep you comfortable.

How is Creutzfeldt-Jakob disease transmitted?

CJD can spread from person to person, but this is very rare. It could happen if something infected with the disease gets inside your body. For example, if you get an organ from a donor and it's infected.

Variant CJD can happen if you eat the meat from a cow who was infected with "mad cow disease." But since an outbreak in the 1990s, many safety rules are now in place to prevent this from happening.

What protein causes Creutzfeldt-Jakob disease?

Prion proteins are naturally in your brain and don't cause any issues. But if they come into contact with an infected ("misfolded") prion, they all begin changing shapes, too. This leads to rapid and widespread problems throughout your body.

How do you prevent CJD?

There is no sure way to make sure you don't get this condition. 

Hospitals have many guidelines in place to minimize your risk of Creutzfeldt-Jakob disease, as well as other health conditions.

If you hunt, avoid handling meat from a deer or elk that acted sick or was dead when you found it. Testing freshly hunted meat before you eat it is also a good idea.