Introduction

What is Creutzfeldt-Jakob disease?

Creutzfeldt-Jakob (kroyts-felt-yak-ob) disease, or CJD, is a rare, degenerative, and fatal neurological disorder. It causes brain damage and progressive changes in the brain’s structure, which leads to problems with muscle coordination, cognition, and memory. This damage results from the accumulation of abnormal proteins known as prions.¹

Importance of understanding CJD

CJD is a severe disease that tends to worsen rapidly, and the prognosis is extremely poor. Symptoms of CJD can greatly vary between patients therefore it is essential to broaden our understanding of the disorder so that CJD can be identified and a timely diagnosis can be provided. Early detection can significantly improve the quality of life and allow the management of symptoms in the best way possible.²

Causes of Creutzfeldt-Jakob disease

There are four types of CJD; each type has a corresponding cause.

Sporadic CJD (sCJD)

The majority of cases of CJD (85%) are of this type. sCJD arises when normal prion proteins in the brain, known as PrP^C (cellular prion protein), misfold and convert to abnormal infectious prions called, PrP^Sc. These abnormal prions aggregate into insoluble amyloid fibrils, causing your brain structure to break down. This results in rapid deterioration of brain function.^3,4,5

Almost all cases of sCJD are fatal within a year of symptoms first presenting. People between the ages of 45-75 years are most likely to be affected; symptoms tend to appear from the ages 60-65. Statistics estimate that each year in the UK only 1 or 2 people in every million are affected by sCJD. 

Familial CJD (fCJD)

This form of CJD is much rarer, accounting for only 5 to 15% of cases. As the name suggests, fCJD occurs if you have inherited a faulty PRNP gene from a parent. As a result, prions form and your nervous system begins to break down. fCJD affects only 1 in every 9 million people in the UK and symptoms tend to present in your early 50s.² 

Iatrogenic CJD (iCJD)

iCJD is caused by infection of prions from contaminated medical or surgical equipment.² Some cases of iCJD are attributable to using human pituitary growth hormones from deceased individuals who may have been infected with CJD. Since 1985, synthetic versions of these growth hormones have been used so the risk of iCJD no longer exists, although cases of the disorder are still being identified many years later.

In surgical cases, for example, a corneal or dura mater graft, if the donor has undiagnosed CJD, the disorder could be passed onto the recipient. However, improved understanding of the transmission of iCJD and strict hygiene measures have drastically reduced its prevalence.

Variant CJD (vCJD)

This type of CJD occurs upon consumption of meat from a cow infected with a similar prion disease known as bovine spongiform encephalopathy (BSE), or ‘mad cow’ disease.² Cases of vCJD are low due to the effective control measures preventing the consumption of meat from infected cattle since the link between CJD and BSE was established in 1996. 

Symptoms of Creutzfeldt-Jakob disease

Initial symptoms

You may notice the following symptoms:^6,7

• Cognitive impairment – this occurs in approximately 35% of cases
• Behavioural changes (e.g., depression, mood swings, anxiety) – this occurs in about 17.5% of cases
• Motor skills impairment
• Lack of coordination (ataxia)
• Confusion
• Insomnia
• Visual changes

Advanced symptoms

As CJD progresses, these symptoms are likely to develop:⁷

• Severe deterioration of cognitive function
• Myoclonus and tremor
• Blindness
• Nystagmus
• Loss of speech
• Paralysis
• Pneumonia and other secondary infections
• Coma

Symptom variation by CJD type

Certain forms of CJD can be characterised by specific symptoms. For example, in the early stages of sCJD, symptoms like memory problems, apathy, and visual changes can occur, in addition to more general symptoms including headache and fatigue. Upon its progression, worsening dementia, myoclonus, and bradykinesia are likely to develop.

Patients with fCJD are typically younger than those with the sporadic form so behavioural and cognitive changes are likely to present first, followed by deterioration of motor skills and the onset of the advanced symptoms listed above.

In vCJD, psychiatric symptoms and behavioural changes are more common than movement problems and dementia, due to the younger age at which the disorder typically appears.²

FAQs

What are the risk factors of CJD?

Research has shown that the following factors may increase your chance of developing CJD:⁸

• Family history of CJD or other dementia-related disorders
• Previous poliomyelitis (polio) infection
• Coming into contact with CDJ-infected medical or surgical equipment (e.g., if you are a patient or healthcare professional)
• Exposure to CDJ-infected cows and other livestock
• Increased age, albeit this is exclusive of vCJD which affects younger adults

How is CJD diagnosed?

A brain biopsy is considered the gold standard for diagnosing the presence of CJD. This procedure involves removing a section of tissue from the brain so it can be examined under a microscope by a pathologist.

How is CJD treated?

There is currently no cure for CJD and many case reports of proposed drug treatments for the condition have produced disappointing results.⁹

Treatment is therefore aimed at providing symptomatic relief to make you feel as comfortable as possible, rather than combating the condition.

Specific medications can be used for the following symptoms:¹⁰

• Psychological symptoms – sedatives (e.g., benzodiazepines, barbiturates), antidepressants (e.g., selective serotonin reuptake inhibitors, tricyclic antidepressants)
• Myoclonus and tremor – clonazepam, sodium valproate
• Pain – non-steroidal anti-inflammatory drugs, opioids

An advance directive or living will, can also be beneficial in CJD treatment. You can state your treatment preferences if you cannot express your decisions at a later stage when your condition has worsened. You may want to specify:

• Where you would like to be treated during the final stages of your condition (e.g., home, hospice, hospital)
• What types of medications you would take if deemed necessary by a healthcare professional
• If you would be willing to have a feeding tube should you no longer be able to feed and drink independently
• If you consent to organ donation or resuscitation if your condition declines

How can I care for someone with CJD?

A CJD diagnosis can be overwhelming and confusing for patients and relatives alike. Although the patient may not need hospice care in the initial stages of their condition, organising care in advance obviates the need to do this later, allowing you to enjoy spending time with the patient without this additional pressure.

Ensuring the patient is comfortable is very important. Consider soft lighting and avoid loud sounds as heightened sensitivity is common in those with CJD.

Finally, it is imperative to take care of yourself as the caregiver. Leading a healthy lifestyle, including getting enough sleep, will allow you to provide the best care possible for the patient.

Summary

CJD is a rare but serious disorder in which abnormal proteins accumulate in the brain, causing symptoms, such as cognitive impairment and behavioural changes. More severe symptoms, including myoclonus, blindness, and paralysis, may occur as the disorder progresses.

There are several types of CJD, the most common of which is sporadic CJD. Other forms are familial, iatrogenic, and variant, caused by genetic mutations, CJD-infected medical equipment, and consumption of CJD-infected cow meat, respectively. There is currently no cure for CJD so treatment is in the form of palliative care instead.