Creutzfeldt-Jakob Disease (CJD) is the most common of a rare group of neurodegenerative pathogens known as human prion diseases. Many researchers believe these diseases are caused by the development of abnormal bundles of proteins, found on the surface of brain cells, called prions. Despite being the most common form of a human prion disease, there are only an estimated 350 cases in the US per year. Unfortunately, the disease has no known cure and is very fatal, leaving most patients dead after anywhere from 4 months to 2 years following their first symptoms.
In this article, I will talk about Creutzfeldt-Jakob Disease in order to address the existence of prions and spread awareness of their destructive capabilities
The disease was first discovered in the 1920s by German neurologists, Hans Gerhard Creutzfeldt and Alfons Maria Jakob. CJD captured the public’s attention in the 1990s when some people in the United Kingdom developed a variant of Creutzfeldt-Jakob disease, vCJD, upon eating meat from diseased cattle. However, the non-variant form of CJD hasn't been linked to infected beef.
CJD is rapidly progressive and invariably fatal. The prion proteins behind it are misfolded isoforms of cellular glycoproteins which come together to become a singular particle: a prion. There are three forms of CJD which one can contract: Sporadic, Familial, and Acquired. Sporadic CJD has no known cause and can happen naturally in anyone. It makes up over 85% of all cases of CJD and usually affects those over the age of 40. Familial CJD occurs when a mutation in the PRNP gene for the PrPC protein causes normal PrPC to change into a disease-causing prion. It accounts for 5 to 15% of cases and occurs at a younger age than sporadic. Acquired CJD happens when one comes in contact with infected material/tissue. There are no confirmed cases of Acquired CJD as of now.
The only way to confirm a diagnosis of CJD is by carrying out a brain biopsy, which is very risky to execute while the patient is still alive. If trying to narrow down the list of possibilities, a neurologist would start by carrying out a series of tests to make sure it isn’t a condition with similar symptoms, such as a brain tumor, Parkinson’s, or Alzheimer’s. These tests may include an MRI brain scan, an EEG, a prototype blood test, a tonsil biopsy, and a genetic test. Another examination involves a lumbar puncture, which can test spinal fluid to rule out other causes of dementia (a symptom of CJD). It can also show if there is an infection or increased pressure in the central nervous system. If 14-3-3 proteins are found in the fluid, and the person is showing typical symptoms, there is a high chance that the person has CJD. During a brain biopsy, a surgeon drills a tiny hole into the skull and removes a small piece of brain tissue using a very thin needle. It’s carried out under general anesthetic, meaning the patient will be unconscious during the procedure. Since a brain biopsy carries the risk of causing brain damage or seizures, it’s only performed in a few cases where there is a concern that someone may not have CJD but some other treatable condition.
Creutzfeldt-Jakob disease is marked by rapid mental deterioration, usually within a few months. Symptoms include personality changes, anxiety, depression, dementia, impaired thinking, blurred vision or blindness, insomnia, difficulty speaking, difficulty swallowing, sudden jerking movements. As the disease progresses over time, the patient’s mental symptoms will worsen. Most infected individuals will eventually go into a coma. Heart and respiratory failure, pneumonia or other infections are generally the cause of death in CJD infected people. For those with the rarer vCJD, psychiatric symptoms may be more prominent in the beginning, with dementia developing later in the illness.
There is no treatment that can slow or stop the brain cell destruction caused by Creutzfeldt-Jakob disease and other prion diseases. Many drugs have been tested, including acyclovir, amantadine, antibiotics, antiviral agents, interferon and steroids, however, none have shown positive results. As of now, the current treatment for CJD aims to ease symptoms and make the person as comfortable as possible. The drugs clonazepam and sodium valproate may help relieve myoclonus. Muscle stiffness and twitching may be treated with muscle-relaxing medications or antiseizure drugs. In the later stages of the disease, individuals with Creutzfeldt-Jakob disease will become completely dependent on others for their daily needs and comfort. As of now, researchers at the UCSF Memory and Aging Center are trying to identify compounds for a treatment or a cure for CJD and other diseases caused by infectious prions.
References:
[1] NINDS. (13/8/2019). Creutzfeldt-Jakob Disease Fact Sheet. National Institute of Health. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-sheets/Creutzfeldt-Jakob-Disease-Fact-Sheet. Retrieved: 12/20/19.
[2] CDC. (9/10/2018). Creutzfeldt-Jakob Disease, Classic (CJD). Center for Disease Control and Prevention. https://www.cdc.gov/prions/cjd/index.html. Retrieved: 12/20/19.
[3] Mayo Clinic. (4/10/2018). Creutzfeldt-Jakob Disease. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/creutzfeldt-jakob-disease/symptoms-causes/syc-20371226. Retrieved: 12/22/19
[4] Medline Plus. (8/5/2019). Creutzfeldt-Jakob Disease. Medline Plus. https://medlineplus.gov/creutzfeldtjakobdisease.html. Retrieved: 12/22/19
[5] Stanford Health Care. Creautzfeldt-Jakob disease (prion disease). Stanford Health Care Organization. https://stanfordhealthcare.org/medical-conditions/brain-and-nerves/dementia/types/prion-disease.html. Retrieved: 12/22/19
[6] Gambetti, Pierluigi. Creutzfeldt-Jakob Disease (CJD) (Subacute Spongiform Encephalopathy). Merck Manuals. https://www.merckmanuals.com/home/brain,-spinal-cord,-and-nerve-disorders/prion-diseases/creutzfeldt-jakob-disease-cjd. Retrieved: 12/22/19
[7] Alzheimer’s Association. Creutzfeldt-Jakob Disease. Alzheimer’s Association. https://www.alz.org/alzheimers-dementia/what-is-dementia/types-of-dementia/creutzfeldt-jakob-disease. Retrieved: 12/23/19
[8] UCSF Health. Creutzfeldt-Jakob Disease Treatments. UCSF Health Organization. https://www.ucsfhealth.org/conditions/creutzfeldt-jakob-disease/treatment. Retrieved: 12/23/19
[9] Kraft, Sy. (26/4/2019). What Is Creutzfeldt-Jakob Disease? Medical News Today. https://www.medicalnewstoday.com/articles/185884.php. Retrieved: 12/24/19
[10] NHS. (14/6/2018). Diagnosis of Creutzfeldt-Jakob Disease. NHS UK. https://www.nhs.uk/conditions/creutzfeldt-jakob-disease-cjd/diagnosis/. Retrieved: 12/24/19