What are other Names for this Condition? (Also known as/Synonyms)

• Common CJD
• sCJD (Sporadic Creutzfeldt-Jakob Disease)
• Sporadic Prion Disease

What is Sporadic Creutzfeldt-Jakob Disease? (Definition/Background Information)

• Sporadic Creutzfeldt-Jakob Disease (sCJD) is a rare, progressive degenerative disease of the brain that occurs spontaneously due to an unknown reason
• The Sporadic form of CJD, or sCJD, may be caused by a random mutation in the gene which codes for the prion protein. Cells that possess this mutation form a dysfunctional prion protein that could (likely) spontaneously form the rogue form of the prion protein
• This spontaneous mutation is referred to as somatic, which is different from an inherited mutation, and cannot be passed down from one generation to another generation
• Prions are infectious pathogens, but are very different from other pathogens, such as bacteria, viruses, and fungi. They are unusual, because they lack both DNA and RNA molecules. Instead, prions are normal cellular proteins that take on an abnormal configuration
• Prions are able to multiply by converting similar normal proteins in the brain into infectious abnormal forms, ultimately leading to the destruction of brain tissue. As a result, individuals with CJD develop dementia, involuntary muscle jerks (myoclonus), loss of motor coordination, and psychiatric symptoms
• There is no cure for sCJD; the treatment provided is often symptomatic. The prognosis of Creutzfeldt-Jakob Disease is usually poor

Creutzfeldt-Jakob Disease is also known as subacute or transmissible spongiform encephalopathy. Several types of CJD exist. All types involve an abnormal form of a naturally-occurring protein in the central nervous system.

• Sporadic Creutzfeldt-Jakob Disease (sCJD) is the most common form of the disorder and accounts for approximately 85% of all cases
• Familial Creutzfeldt-Jakob Disease (fCJD) is an inherited form caused by genetic mutations on chromosome 20
• Iatrogenic Creutzfeldt-Jakob Disease (iCJD) is an unintended consequence of medical therapy
• New Variant (or Variant) Creutzfeldt-Jakob Disease (nvCJD or vCJD) is due to the consumption of contaminated beef from cattle affected by a similar disease, called bovine spongiform encephalopathy (BSE)

Who gets Sporadic Creutzfeldt-Jakob Disease? (Age and Sex Distribution)

• Creutzfeldt-Jakob Disease is found worldwide with an incidence of approximately 1 case per 1,000,000 people
• Sporadic Creutzfeldt-Jakob Disease is the most common form of CJD. It can affect individuals of any age, but most individuals are 50-75 years old
• Both males and females are equally affected and no particular preference is observed
• Sporadic Creutzfeldt-Jakob Disease does not show higher prevalence in any specific racial, ethnic, or geographical group

What are the Risk Factors for Sporadic Creutzfeldt-Jakob Disease? (Predisposing Factors)

There are currently no known risk factors for developing Sporadic Creutzfeldt-Jakob Disease due to the spontaneous nature of this form of CJD. Research is currently being undertaken to identify potential links between certain gene commonalities and a higher prevalence of sCJD.

• The only definitive risk factor for Sporadic Creutzfeldt-Jakob Disease is associated with age and is therefore unavoidable. The onset of sCJD typically occurs between the ages of 50-75 with the average age being 60 years
• It is important to note that all forms of Creutzfeldt-Jakob Disease are not contagious via air or casual contact. Having close interactions with or living with an individual who has CJD does not increase one’s risk for developing CJD
• However, contact with spinal cord fluid or brain tissue from an infected individual can result in the development of Creutzfeldt-Jakob Disease

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Sporadic Creutzfeldt-Jakob Disease? (Etiology)

• Sporadic Creutzfeldt-Jakob Disease is caused by a spontaneous genetic mutation that creates abnormal prion proteins. Spontaneous mutations may be responsible for both sporadic and familial cases of CJD
• The period during which the mutated forms of the prion protein are being replicated is called the incubation period. This phase can be as long as 50 years, during which no clinical signs or symptoms are observed
• The abnormal prion proteins are able to recruit more mutated forms of the protein in the brain and convert normal prion proteins into the misshapen form. Accumulation of these abnormally shaped prion proteins in the brain are what cause CJD and the associated dementia symptoms
• The abnormal form of prion proteins are not able to be broken down by enzymes, like the normal type. The standard function of normal prion proteins in the brain is relatively unclear, but it is believed that they play a role in the transmission of signals between brain cells

What are the Signs and Symptoms of Sporadic Creutzfeldt-Jakob Disease?

The signs and symptoms of all forms of CJD are very similar; thus, the features of Sporadic Creutzfeldt-Jakob Disease may include:

• Some individuals may initially experience fatigue, sleep disturbances, hallucinations, weight loss, headaches, and pain
• The initial symptoms in most individuals are mainly cognitive and include memory loss, confusion, and impaired judgment
• Some have vision, speech, or gait disturbances
• Other possible symptoms include rigidity, uncontrollable limb movements, poor coordination, and seizures
• Sudden, loud noises or bright light may trigger myoclonus (involuntary twitching of muscles). This may also occur during sleep
• Depression and sensory disturbances are common in sCJD
• In all cases, the symptoms progress to profound dementia

How is Sporadic Creutzfeldt-Jakob Disease Diagnosed?

A diagnosis of Sporadic Creutzfeldt-Jakob Disease may involve:

• Complete evaluation of medical history and a thorough physical examination; a positive family history may help diagnose familial CJD in a minority of cases
• Symptoms of dementia, myoclonus, and an abnormal EEG, in a middle-aged individual may suggest a diagnosis of Creutzfeldt-Jakob Disease
• Brain MRI may be helpful in diagnosing Sporadic CJD
• A spinal tap is usually sufficient in identifying the presence of abnormal prion proteins
• CJD may be confirmed by brain tissue biopsy and assays that detect abnormal prion proteins. If a biopsy is negative, the diagnosis of CJD may not be ruled out, because prion proteins may be absent from a small tissue sample. In such cases, a final diagnosis cannot be made until autopsy

The following clinical criteria and specialized diagnostic tests results are standard for diagnosing an individual with Sporadic Creutzfeldt-Jakob Disease (created by The Cleveland Clinic Foundation, USA).

An individual with sCJD will show the following symptoms:

• Cerebellar and/or visual disturbance
• Pyramidal and/or extrapyramidal symptoms
  • Pyramidal symptoms include muscle spasms, restlessness, tremor, irregular jerky movements, and parkinsonism
  • Extrapyramidal symptoms are drug-induced side effects from the use of antipsychotic drugs
• Jerky muscle group contractions (myoclonus)
• Individuals tending not to move or speak (akinetic mutism)

Specialized diagnostic tests can be carried out, and the following result criteria would indicate a positive diagnosis for Sporadic Creutzfeldt-Jakob Disease:

• Periodic sharp wave complexes when viewed on an electroencephalogram (EEG)
• The protein 14-3-3 would be present in the spinal fluid
• Hypersensitivity in caudate nucleus and striatum or at least two cortical regions (excluding frontal) on diffusion weighted imaging and/or fluid attenuated inversion recovery sequences. This means that there are specific abnormalities in certain parts of brain tissue on radiological imaging of the brain

(Source: The Cleveland Clinic Foundation, Lyndhurst, Ohio)

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Sporadic Creutzfeldt-Jakob Disease?

The complications of Sporadic Creutzfeldt-Jakob Disease may include:

• Frequent development of pneumonia during the later stages of the disease which is often fatal
• Severe dementia may cause significant stress and social issues for the individual with Creutzfeldt-Jakob Disease, as well as on their caretakers

How is Sporadic Creutzfeldt-Jakob Disease Treated?

There are currently no effective treatments available for Sporadic Creutzfeldt-Jakob Disease.

• Quinacrine has shown to slow the rate of neurological decline in some patients
• The affected individuals receive supportive care and may be given medications to control myoclonus and pain, if present
• Treatments in development for CJD include the use of antibodies against prions and several drugs with potential therapeutic efficacy

How can Sporadic Creutzfeldt-Jakob Disease be Prevented?

Sporadic Creutzfeldt-Jakob Disease, and CJD in general, is not preventable due to its spontaneous method of development. On the other hand, certain forms of Creutzfeldt-Jakob Disease may be transmitted to others while not exercising due care when handling infected brain tissue.

• For example, prions may be transmitted to healthcare workers through accidental needle sticks or stab wounds from materials that have come into contact with brain tissue from an infected individual
• It is very important to sterilize by autoclave, any equipment that has had contact with brain tissue from patients with CJD

What is the Prognosis of Sporadic Creutzfeldt-Jakob Disease? (Outcomes/Resolutions)

• There is a highly variable incubation period in Creutzfeldt-Jakob Disease, following the transmission of prions. Symptoms have been observed in as few as 1-2 years, or after as many as 30 years, especially in the case of new variant CJD
• Individuals diagnosed with CJD may live 3 months to 5 years following onset of symptoms. However with CJD, in a majority of cases, death usually results in less than 1 year
• 5-10% of the patients survive more than 2 years.  Patients with familial CJD tend to live longer than those with Sporadic Creutzfeldt-Jakob Disease

Additional and Relevant Useful Information for Sporadic Creutzfeldt-Jakob Disease:

There are voluntary organizations and support groups that provide counsel, help, and understanding to the individuals and families affected by Creutzfeldt-Jakob Disease.