What Is Creutzfeldt-Jakob Disease (CJD)? What Is Mad Cow Disease?
Creutzfeldt-Jakob disease (CJD) is a rare neurodegenerative disease that rapidly, progressively and severely affects the brain. Creutzfeldt-Jakob disease is one cause of dementia and results in the destruction of brain cells in the brain. Creutzfeldt-Jakob disease eventually leads to the development of many tiny holes in the brain. The disease was first described by German neurologist Hans Gerhard Creutzfeldt in 1920, and shortly afterwards by Alfons Maria Jakob, giving it the name Creutzfeldt-Jakob.
According to Medilexicon’s medical dictionary:
Creutzfeldt-Jakob disease is a progressive neurologic disorder, one of the subacute spongiform encephalopathies caused by prions. Clinical features of CJD include a progressive cerebellar syndrome, including ataxia, abnormalities of gait and speech, and dementia. In most patients, these symptoms are followed by involuntary movements (myoclonus) and the appearance of a typical electroencephalogram pattern (burst suppression, consisting of intermittent sharp and slow wave complexes on a flat background). Changes in the CSF are absent or nonspecific. Mild cortical atrophy and ventricular dilation may be grossly evident. On microscopic examination the distinctive finding is spongiform encephalopathy in gray matter throughout the brain and spinal cord. Severe neuronal loss and gliosis are also present and mild demyelination may occur. Ultrastructural changes include formation of intracytoplasmic vacuoles, which account for the spongy appearance.
The disease is a seriously disabling and devastating disorder that progressively damages and destroys a person’s memory, vision, and ability to think and move voluntarily, and function independently. Creutzfeldt-Jakob disease is one of a variety of transmissible spongiform encephalopathies (TSEs). Creutzfeldt-Jakob disease is not curable and is eventually fatal.
CJD occurs worldwide at a rate of about 1 or 2 cases per million population per year. Most cases are sporadic, but 10 to 12% are inherited. The peak incidence is between 55 and 65 years of age, and the disease is rare before age 30. The average survival time is less than one year after onset of symptoms.
Cases of iatrogenic CJD have been associated with corneal transplants, electrode implants, dura mater grafts, and administration of human growth hormone. CJD is caused by a prion protein (an abnormal isoform of amyloid protein) that serves as a nucleating factor, inducing abnormalities in other proteins. This protein is detectable by Western blot testing early in the course of clinical disease.
Other prion diseases include Gerstmann-Sträussler-Scheinker (GSS) syndrome, fatal familial insomnia, and kuru in humans; scrapie in sheep and goats; and bovine spongiform encephalopathy (BSE, mad cow disease) in cattle. Similar encephalopathies and wasting syndromes are found in other species. All these diseases have been shown to be transmissible in laboratory animals.
What are the symptoms of Creutzfeldt-Jakob disease?
A symptom is something the patient senses and describes, while a sign is something other people, such as the doctor notice. For example, drowsiness may be a symptom while dilated pupils may be a sign.
CJD usually starts with emotional or behavioral problems such as depression, anxiety or agitation. Delusions and hallucinations are typical of variant CJD. Patients also develop neurological problems, such as pain or numbness in parts of their body.
Symptoms of Creutzfeldt-Jakob disease occur most often in the elderly, after the age of 60. Symptoms are due to the destruction of brain cells and include neurological symptoms, such as memory loss, blindness, and poor coordination. Within a few weeks, the person deteriorates rapidly, becoming confused and experiencing memory loss (symptoms typical of dementia). Symptoms of Creutzfeldt-Jakob disease eventually progress to become severely disabling, and coma and death eventually occur.
Some symptoms of CJD can be similar to symptoms of other progressive neurological disorders, such as Alzheimer’s or Huntington’s disease. However, CJD causes unique changes in brain tissue which can be seen at autopsy. It also tends to cause more rapid deterioration of a person’s abilities than Alzheimer’s disease or most other types of dementia.
What are the causes of Creutzfeldt-Jakob disease?
About 5 to 10 percent of all CJD cases are inherited. These cases arise from a mutation, or change, in the gene that controls formation of the normal prion protein. While prions themselves do not contain genetic information and do not require genes to reproduce themselves, infectious prions can arise if a mutation occurs in the gene for the body’s normal prion protein.
If the prion protein gene is altered in a person’s sperm or egg cells, the mutation can be transmitted to the person’s offspring. Several different mutations in the prion gene have been identified. The particular mutation found in each family affects how frequently the disease appears and what symptoms are most noticeable. However, not all people with mutations in the prion protein gene develop CJD.
Some researchers believe an unusual “slow virus” or another organism causes CJD. However, they have never been able to isolate a virus or other organism in people with the disease. Furthermore, the agent that causes CJD has several characteristics that are unusual for known organisms such as viruses and bacteria.
It is difficult to kill, it does not appear to contain any genetic information in the form of nucleic acids (DNA or RNA), and it usually has a long incubation period before symptoms appear. In some cases, the incubation period may be as long as 40 years. The leading scientific theory at this time maintains that CJD and the other TSEs are caused not by an organism but by a type of prion protein.
Diagnosing Creutzfeldt-Jakob disease
First one will notice the onset of dementia, including memory loss, hallucinations, changes in personality and nervous tension. These mental disorders are accompanied by physical changes such as clumsiness, lack of balance, change of gait, muscle twitches and stiffness and speech impediments. As the disease progresses the patient becomes delirious and exhibits extreme confusion and disorientation.
A patient examination to notice exceptionally quick reflexes, excessively toned or possibly withered muscles (depending on the patient’s reaction to the disease) and muscle spasms. A visual exam often reveals partial blindness that the patient had not noticed on their own.
A doctor can schedule an electroencephalogram (EEG) to look for certain signs characteristic of Creutzfeldt-Jakob disease. If the patient has had symptoms of the disease for at least three months the results will show on the EEG. This is not a final diagnostic test but suggests whether more testing should be done.
More seriously, a physician may perform a spinal tap. The spinal fluid of the patient is tested for presence of the protein 14-3-3. This test, if results show proteins in the fluid, is highly indicative of the presence of Creutzfeldt-Jakob disease if accompanied by other symptoms.
Finally a doctor will proceed with a brain biopsy if the other tests positively point toward CJD. If a patient is a victim of this disease the brain tissue is spongy; using a microscope you can see tiny holes where clumps of nerve cells have been killed. This is the only definitive way to diagnose the disease, other than an autopsy.
What are the treatment options for Creutzfeldt-Jakob disease?
Creutzfeldt-Jakob disease is an incurable neurological disorder.
It causes a build-up and malformation of prions (a type of protein) on the brain cells ultimately leading to brain damage and death. There is no cure yet, but doctors feel they are making some headway into prolonging the life of those suffering from this disease.
Current treatment for CJD is aimed at alleviating symptoms and making the patient as comfortable as possible. Opiate drugs can help relieve pain if it occurs, and the drugs clonazepam and sodium valproate may help relieve myoclonus. During later stages of the disease, changing the person’s position frequently can keep him or her comfortable and helps prevent bedsores. A catheter can be used to drain urine if the patient cannot control bladder function, and intravenous fluids and artificial feeding also may be used.
Preventing Creutzfeldt-Jakob disease
Medical equipment is sterilized to kill organisms that may cause the disease. Persons who have a medical history of diagnosed or possible CJD are not used as cornea donors.
Most countries now have strict guidelines for management of infected cows and strict restrictions regarding what they are fed, to avoid the potential for transmission of CJD to humans.
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