Creutzfeldt-Jakob Disease – Symptoms and Causes

Overview

Creutzfeldt-Jakob disease (CJD) is a rare brain disorder that causes rapid dementia and belongs to a group called prion disorders. While its symptoms may resemble Alzheimer’s disease, CJD progresses much faster and is fatal.

The condition gained attention in the 1990s when some people contracted a variant form (vCJD) after consuming meat from infected cattle. However, most CJD cases aren’t linked to beef consumption.

This serious condition affects approximately 1-2 people per million worldwide each year and is more common in older adults. Though all types of CJD are concerning, they remain extremely rare.

Patients typically experience rapidly worsening confusion, coordination problems, and memory loss as the disease damages brain tissue.

Diagnosis usually involves several tests, including:

• Brain MRI scans
• Spinal fluid analysis
• Electroencephalogram (EEG)
• Neurological examinations

Early recognition is important, though unfortunately there is currently no cure for this condition.

Signs and Symptoms

Creutzfeldt-Jakob disease presents with rapidly progressing symptoms that typically worsen within weeks to months. Early warning signs include:

• Mental changes: Personality shifts and memory problems.
• Cognitive decline: Impaired thinking abilities.
• Vision issues: Blurriness or loss of sight.
• Sleep problems: Difficulty falling or staying asleep.
• Physical difficulties: Poor coordination and balance.
• Communication problems: Trouble with speech and swallowing.
• Movement disorders: Sudden jerky movements or twitching.

Most patients survive less than a year after symptoms appear. Death typically results from complications like swallowing problems, falls, heart issues, lung failure, or infections such as pneumonia.

Variant CJD shows some differences from the classic form. Mental changes often appear earlier, while dementia may develop later in the disease course. This variant typically affects younger people and runs its course in about 12-14 months.

Another rare form called variably protease-sensitive prionopathy (VPSPr) can look similar to other types of dementia.

This form causes cognitive changes and problems with speech and thinking skills, but progresses more slowly than other prion diseases—usually lasting about 24 months before death.

What Causes Prion Diseases

Prions are natural proteins found in the brains of humans and animals. Normally, these proteins are harmless and perform regular functions. However, when prions misfold into abnormal shapes, they can cause serious brain disorders.

The misfolding process happens when a normal prion encounters an abnormal one. This triggers a chain reaction where the normal protein changes its shape to match the abnormal one.

These misshapen proteins then:

• Clump together in brain tissue
• Spread to neighboring cells
• Disrupt normal brain functions
• Cause progressive damage to brain cells

Unlike bacteria or viruses, prions don’t contain genetic material. This makes them extremely resistant to standard sterilization methods that target DNA or RNA.

Development of Creutzfeldt-Jakob Disease

Creutzfeldt-Jakob disease (CJD) is rare, with only about one case per million people annually. It cannot spread through casual contact, coughing, sneezing, or sexual activity. There are three main ways people develop CJD:

• Sporadic CJD: The most common form, accounting for about 85% of all cases. It appears randomly with:
  • No identifiable cause
  • No apparent risk factors
  • Typically affects people over 60
  • Progresses more rapidly than other forms
• Genetic CJD: Approximately 10-15% of cases are inherited. These cases:
  • Result from mutations in the PRNP gene
  • Can be detected through genetic testing
  • Often develop at younger ages than sporadic cases
  • Include rare variants like Gerstmann-Straussler-Scheinker syndrome and fatal familial insomnia
• Acquired CJD: The least common form, occurring when someone is exposed to infectious prion material. Sources include:

Exposure Type	Description
Medical procedures	Contaminated surgical instruments, cornea transplants
Growth hormone	Earlier treatments using human-derived pituitary hormones
Contaminated food	Eating beef infected with bovine spongiform encephalopathy (BSE or “mad cow disease”)

Acquired cases from medical procedures are called iatrogenic CJD. Those from contaminated beef are known as variant CJD. Modern safety measures have significantly reduced these risks.

Risk Factors

Several factors may increase a person’s chance of developing Creutzfeldt-Jakob disease (CJD), though most cases occur without any known cause.

Genetic Inheritance

Familial CJD follows a specific inheritance pattern where the disease-causing gene can pass from parent to child. If one parent carries the altered gene, each child has a 50% chance of inheriting it.

This form of CJD typically appears when people are in their 50s, slightly earlier than the sporadic form.

People with family members who have had CJD should consider genetic counseling to understand their risk. The inheritance follows what scientists call an “autosomal dominant” pattern, meaning just one copy of the altered gene will cause the disease.

Inheritance Risk at a Glance:

• One parent with the gene = 50% risk for each child
• The gene passes equally to sons and daughters
• The disease will develop if the gene is inherited

Other risk factors include:

• Age: Sporadic CJD most often affects people around age 60, while the variant form (vCJD) typically appears in much younger people, often in their late 20s.
• Tissue Exposure: Some people have developed CJD after receiving:
  • Contaminated human growth hormone
  • Brain covering (dura mater) transplants from infected donors
  • Exposure to contaminated surgical instruments

The risk of getting vCJD from beef is extremely low in countries with strong food safety measures. While chronic wasting disease affects deer and similar animals in North America, no human cases from this source have been confirmed.

Health officials monitor these risks carefully to protect public health and prevent new cases whenever possible.

Complications

CJD causes severe damage to the brain and progresses rapidly. As the disease advances, patients typically become socially withdrawn, unable to maintain relationships with family and friends. Their ability to perform basic self-care tasks steadily declines.

Many patients eventually enter a comatose state. Despite medical intervention, CJD has a 100% mortality rate, making it invariably fatal for those diagnosed.

Ways to Reduce Risk

Hospitals follow strict guidelines to prevent the spread of Creutzfeldt-Jakob disease through medical procedures. These safety measures include:

• Using synthetic growth hormone instead of hormone taken from human pituitary glands
• Properly destroying surgical tools that may have contacted brain or nerve tissue of infected patients
• Implementing single-use kits for procedures like spinal taps

Blood donation centers protect the blood supply by screening out high-risk donors. People cannot donate blood if they:

• Have family members diagnosed with familial forms of the disease
• Received a dura mater (brain covering) graft
• Were treated with human growth hormone from cadavers

Many countries have specific rules about who can donate blood based on exposure risk.

Limiting Exposure to the Variant Form

The chance of getting variant Creutzfeldt-Jakob disease in the United States is extremely low. Only four cases have been reported, and evidence suggests these infections happened outside the country.

The United Kingdom saw the highest number of cases – fewer than 200 total. Cases peaked around 1999-2000 and have decreased since then. A small number of cases have appeared in other countries worldwide.

No evidence shows that people can develop the disease from eating meat from animals with chronic wasting disease. However, hunters should take precautions in areas where this condition exists:

1. Test deer and elk meat before eating it
2. Avoid handling or shooting animals that appear sick
3. Don’t process animals found dead

Food Safety Regulations

Countries worldwide have implemented rules to keep infected meat out of the food supply. These protective measures include:

Import restrictions

• Strict limits on cattle imports from high-risk countries

Farming practices

• Controls on animal feed content
• Clear procedures for handling sick animals

Monitoring systems

• Testing methods to track cattle health
• Surveillance programs to detect problems early

Processing rules

• Limits on which animal parts can be used for food

These efforts help protect the public from exposure to potentially contaminated animal products.