About subacute spongiform encephalopathy
What is subacute spongiform encephalopathy?
Creutzfeldt-Jakob disease (CJD) is an extremely rare degenerative brain disorder (i.e., spongiform encephalopathy) characterized by sudden development of rapidly progressive neurological and neuromuscular symptoms. With symptom onset, affected individuals may develop confusion, depression, behavioral changes, impaired vision, and/or impaired coordination. As the disease progresses, there may be rapidly progressive deterioration of cognitive processes and memory (dementia), resulting in confusion and disorientation, impairment of memory control, personality disintegration, agitation, restlessness, and other symptoms and findings. Affected individuals also develop neuromuscular abnormalities such as muscle weakness and loss of muscle mass (wasting); irregular, rapid, shock-like muscle spasms (myoclonus); and/or relatively slow, involuntary, continual writhing movements (athetosis), particularly of the arms and legs. Later stages of the disease may include further loss of physical and intellectual functions, a state of unconsciousness (coma), and increased susceptibility to repeated infections of the respiratory tract (e.g., pneumonia). In many affected individuals, life-threatening complications may develop less than a year after the disorder becomes apparent.
In approximately 90 percent of cases, CJD appears to occur randomly for no apparent reason (sporadically). About 10 percent of affected individuals may have a hereditary predisposition for the disorder. Reports in the medical literature suggest that familial cases of CJD are consistent with an autosomal dominant mode of inheritance. In addition, in some extremely rare cases, CJD may take an infectious form. The disorder is thought to result from changes (mutations) in the gene that regulates the production of the human prion protein or direct contamination (transmission) with abnormal prion protein in infected brain tissue.
A variant form of CJD (V-CJD) has been reported in the United Kingdom that affects younger people (median age at onset: 28 years) than does classic CJD. In 1996, experts suggested the possibility that this variant might be associated with consumption of beef from cows with a related infectious brain disorder known as Bovine Spongiform Encephalopathy (BSE) or "Mad Cow Disease." BSE was first identified in the UK in 1986 and the number of reported cases grew rapidly, peaking in the winter of 1992-93 when almost 1,000 new cases were reported each week. Later, BSE also began to appear in some other European countries. Scientific research and debate continue concerning the potential link between BSE and V-CJD. In addition, coordinated national and international efforts are in place concerning the prevention, study, and surveillance of BSE and CJD. In early December 2000, European Union agriculture ministers agreed upon new measures to combat the spread of mad cow disease, including incinerating any cow over 30 months of age that had not tested negative for BSE. (BSE is thought to become detectable and infectious when cattle are approximately 30 months old.)
What are the symptoms for subacute spongiform encephalopathy?
Jerky movements symptom was found in the subacute spongiform encephalopathy condition
As the disease progresses, mental symptoms worsen. Most people eventually fall into a coma. Heart failure, lung (respiratory) failure, pneumonia or other infections are generally the cause of death, which usually occurs within a year.
In people with the rarer vCJD, psychiatric symptoms may be more apparent in the beginning. In many cases, Dementia — the loss of the ability to think, reason and remember — develops later in the illness. vCJD also affects people at a younger age and appears to last 12 to 14 months.
What are the causes for subacute spongiform encephalopathy?
How prions fold
Prions are proteins that occur naturally in the brains of animals and people. Normally, the proteins are harmless, but when they're misshapen, they can cause devastating illnesses such as BSE disease in cattle and Creutzfeldt-Jakob disease in humans.
Creutzfeldt-Jakob disease and its variants belong to a broad group of human and animal diseases known as transmissible spongiform encephalopathies (TSEs). The name derives from the spongy holes, visible under a microscope, that develop in affected brain tissue.
The cause of Creutzfeldt-Jakob disease and other TSEs appears to be abnormal versions of a kind of protein called a prion. Normally these proteins are produced in our bodies and are harmless. But when they're misshapen, they become infectious and can harm normal biological processes.
How CJD is transmitted
The risk of CJD is low. The disease can't be spread through coughing or sneezing, touching, or sexual contact. CJD can develop in three ways:
- Sporadically. Most people with classic CJD develop the disease for no apparent reason. This type, called spontaneous CJD or sporadic CJD, accounts for most cases.
- By inheritance. Fewer than 15% of people with CJD have a family history of the disease or test positive for a genetic mutation associated with CJD. This type is referred to as familial CJD.
By contamination. A small number of people have developed CJD after being exposed to infected human tissue during a medical procedure, such as a cornea or skin transplant. Also, because standard cleaning methods don't destroy abnormal prions, a few people have developed CJD after undergoing brain surgery with contaminated instruments. A small number of people have also developed the disease from eating contaminated beef.
Cases of CJD related to medical procedures are referred to as iatrogenic CJD. Variant CJD is linked primarily to eating beef infected with mad cow disease (bovine spongiform encephalopathy, or BSE).
What are the treatments for subacute spongiform encephalopathy?
No effective treatment exists for Creutzfeldt-Jakob disease or any of its variants. Many drugs have been tested and haven't shown benefits. For that reason, doctors focus on relieving pain and other symptoms and on making people with these diseases as comfortable as possible.
What are the risk factors for subacute spongiform encephalopathy?
Autosomal dominant inheritance pattern
In an autosomal dominant disorder, the altered gene is a dominant gene located on one of the nonsex chromosomes (autosomes). You need only one altered gene to be affected by this type of disorder. A person with an autosomal dominant disorder — in this case, the father — has a 50% chance of having an affected child with one altered gene (dominant gene) and a 50% chance of having an unaffected child with two typical genes (recessive genes).
Most cases of Creutzfeldt-Jakob disease occur for unknown reasons, and no risk factors can be identified. However, a few factors seem to be associated with different kinds of CJD:
- Age. Sporadic CJD tends to develop later in life, usually around age 60. Onset of familial CJD occurs slightly earlier, and vCJD has affected people at a much younger age, usually in their late 20s.
- Genetics. People with familial CJD have a genetic mutation that causes the disease. To develop familial CJD, a child must have one copy of the mutated gene, which is inherited from either parent. If you have the mutation, the chance of passing it on to your children is 50%.
Exposure to contaminated tissue. People who've received infected manufactured human growth hormone, or who've had transplants of the infected tissues that cover the brain (dura mater), may be at risk of iatrogenic CJD.
The risk of getting vCJD from eating contaminated beef is very low. In general, if countries are effectively implementing public health measures, the risk is virtually nonexistent. Chronic wasting disease (CWD) is a prion disease that affects deer, elk, reindeer and moose. It has been found in some areas of North America. To date, no documented cases of CWD have caused disease in humans.
Is there a cure/medications for subacute spongiform encephalopathy?
Subacute spongiform encephalopathy is also known as Creutzfeldt-Jakob disease (CJD), which is a degenerative brain condition that causes dementia and, eventually, death. Symptoms of Creutzfeldt-Jakob disease may resemble those of dementia-like brain illnesses, such as Alzheimer's. However, Creutzfeldt-Jakob disease normally advances much faster.
CJD first gained public notice in the 1990s, when several persons in the United Kingdom contracted a form of the disease known as variant CJD after consuming meat from sick cattle. However, tainted beef has not been associated with "classic" Creutzfeldt-Jakob disease. All kinds of CJD are dangerous, but they are extremely rare. Every year, around one to two scenarios of CJD are detected per million individuals worldwide, with the majority of cases occurring in elderly adults.
Creutzfeldt-Jakob disease and its variants are classified as transmissible spongiform encephalopathies in humans and animals (TSEs). The name comes from the spongy pores that appear under a microscope in afflicted brain tissue.
Creutzfeldt-Jakob disease and other TSEs appear to be caused by aberrant forms of a protein known as a prion. These proteins are normally synthesized in our systems and are completely innocuous. When they become malformed, though, they become contagious and can disrupt regular biological processes.
1. Creutzfeldt-Jakob disease and its variations have no effective treatment.
2. Many medications have been studied and found to be ineffective.
3. As a result, doctors concentrate on treating pain and other symptoms and making patients as comfortable as possible.
Personality changes,Memory loss,Impaired thinking,Blurred vision or blindness,Insomnia,Incoordination,Difficulty speaking,Difficulty swallowing,Sudden, jerky movements
Heart failure,Lung (respiratory) failure,Pneumonia