Creutzfeldt-Jakob Disease
Creutzfeldt-Jakob disease (CJD) is a rare, degenerative, invariably fatal brain disorder. Typically, onset of symptoms occurs at about age 60. There are three major categories of CJD: sporadic CJD, hereditary CJD, and acquired CJD. There is currently no single diagnostic test for CJD. The first concern is to rule out treatable forms of dementia such as encephalitis or chronic meningitis. The only way to confirm a diagnosis of CJD is by brain biopsy or autopsy. In a brain biopsy, a neurosurgeon removes a small piece of tissue from the patient's brain so that it can be examined by a neurologist. Because a correct diagnosis of CJD does not help the patient, a brain biopsy is discouraged unless it is need to rule out a treatable disorder. While CJD can be transmitted to other people, the risk of this happening is extremely small.
Causes
Transmissible spongiform encephalopathy diseases (also known as prion diseases) are caused by a unique type of infectious agent called a prion, an abnormally structured form of a protein found in the brain. Other prion diseases include Gerstmann-Sträussler-Scheinker syndrome (GSS), fatal familial insomnia (FFI) and kuru in humans, as well as bovine spongiform encephalopathy (BSE) commonly known as mad cow disease, chronic wasting disease (CWD), and scrapie in sheep.
The prion that is believed to cause Creutzfeldt-Jakob exhibits at least two stable conformations. One, the native state, is water-soluble and present in healthy cells. As of 2006, its biological function is unknown. The other conformational state is very poorly water-soluble and readily forms protein aggregates.
The Creutzfeldt-Jakob disease prion is dangerous because it promotes refolding of native proteins into the diseased state. The number of misfolded protein molecules will increase exponentially, and the process leads to a large quantity of insoluble prions in affected cells. This mass of misfolded proteins disrupts cell function and causes cell death. Once the prion is transmitted, the defective proteins invade the brain and are produced in a self-sustaining feedback loop, causing exponential spread of the prion, death within a few months, although a few patients have been known to live as long as two years.
Symptoms
- Dementia
- Memory Loss
- Personality Changes
- Hallucinations
The symptoms of Creutzfeldt-Jakob disease are caused by the progressive death of the brain's nerve cells, which is associated with the build-up of abnormal prion proteins. When brain tissue from a CJD patient is examined under a microscope, many tiny holes can be seen where whole areas of nerve cells have died. The word 'spongiform' in 'transmissible spongiform encephalopathies' refers to the 'spongy' appearance of the brain tissue.
Transmission
The defective protein can be transmitted by human growth hormone (HGH) products, corneal grafts, dural grafts or electrode implants (acquired or iatrogenic form: iCJD); it can be inherited (hereditary or familial form: fCJD); or it may appear for the first time in the patient (sporadic form: sCJD). In the hereditary form, a mutation occurs in the gene for PrP, PRNP. 10 to 15 percent of Creutzfeldt-Jakob disease cases are inherited. (CDC) The issue of transmission is a vexing one for hospitals: prion proteins adhere to re-usable instruments and are not destroyed by conventional methods of decontamination (e.g., autoclaving), and contaminated instruments have simply to be discarded. Copper-hydrogen peroxide has been suggested as a potential method of decontamination, but this work is at a very preliminary stage.
Treatment
There is no treatment that can cure or control CJD. Current treatment is aimed at alleviating symptoms and making the patient as comfortable as possible. Opiate drugs can help relieve pain, and the drugs clonazepam and sodium valproate may help relieve involuntary muscle jerks.
Informations obtained from National Institute of Health.