Prion proteins are responsible for the rare, fatal degenerative brain condition known as Creutzfeldt-Jakob disease (CJD). It is a member of a class of spongiform encephalopathies that are transmissible and have an annual...
Prion proteins are responsible for the rare, fatal degenerative brain condition known as Creutzfeldt-Jakob disease (CJD). It is a member of a class of spongiform encephalopathies that are transmissible and have an annual incidence of one case per million persons worldwide.
The neurodegenerative disease Creutzfeldt-Jakob disease (CJD), which is caused by prion proteins, is swiftly progressing, uncommon, transmissible, and always deadly. Alfons Jakob later defined this syndrome in 1921 and 1923 after Hans Creutzfeldt initially introduced it in 1920. Later, because the acronym was closer to his initials, Clearance J. Gibbs began referring to the condition as Creutzfeldt-Jacob disease (CJD).
Etiology
CJD is a member of the group of prion diseases, also known as transmissible spongiform encephalopathies, which can lead to a variety of lethal neurodegenerative conditions in both people and animals. The infectious substance is called "prion" (a protein), and it can spread either by familial inheritance of a mutation in the prion protein gene or through direct contact with tissue that has been contaminated (iatrogenic). But CJD is typically irregular in occurrence.
In reference to the previously unidentified infection caused by protein misfiling in 1982, the words "proteinaceous" and "infectious" were combined to produce the word "prion." Stanley Prusiner, who won the 1997 Nobel Prize in physiology or medicine for his work on prions, is credited for giving the term "prion" and discovering it.
TYPES OF CJD :
Sporadic
The most prevalent CJD variant
For 85% of instances
suddenly and without apparent cause
The peak onset age is between 55 and 75 years old, with a mean age of 61 years and a median age of 68.
90% of patients pass away within a year, and the average survival time is 4 to 8 months.
Genetic/Familial
The second most prevalent variety of CJD
10% to 15% of the time.
Possibly has a family history and tested positive for a genetic mutation.
Resulting from acquired autosomal dominant mutations in the prion protein-encoding PRNP gene
oral or iatrogenic transfer from a human or animal. When exposed to the infected brain or nervous tissue during specific surgical procedures, transmission happens.
An Alternate Form of CJD
a disease that affects cattle and is known as "mad cow" disease or bovine spongiform encephalopathy (BSE), is contracted by eating infected beef. Most occurrences have happened in France and the United Kingdom.
Epidemiology
In the entire world, one person per million is affected by the Creutzfeldt-Jakob disease (CJD). Each year, the United States receives a diagnosis for about 350 instances. The most prevalent type of human prion disease is sporadic CJD, and the average age at which it manifests is 61. Within a year after commencement, death occurs in close to 70% of patients.
Pathophysiology
Even in healthy individuals and animals, normal cellular prion protein (PrP) can be found on cell membranes all over the body. We still don't fully understand all of its intricate functions. The prion PrP scrapie (also known as the prion disease of sheep and goats), which self-replicates and builds up throughout the brain, is the disease-causing variant of the normally healthy cellular prion protein PrP that is responsible for CJD.
By causing a structural change in native prion proteins, the infectious isoform known as PrP scrapie causes the normal PrP proteins to transform into the infectious isoform (PrP scrapie), which explains its infectious capacity. Both the buildup of prions and the conversion of prion proteins into prions are thought to contribute to the development of neurodegeneration
Symptoms
The most prevalent prion disease affecting people is sporadic CJD. Typically, it appears as a rapidly developing dementia accompanied by ataxia and myoclonus, which can occasionally cause death in less time than a year. With a peak age of start between 55 and 75 years old, the median age of death, and a median illness duration of 4 to 5 months, it typically affects older people. It has early neurological symptoms and a similar presentation to dementia, but it advances much more quickly.
Patients may have vertigo, headaches, tiredness, and sleep difficulties in the early stages of sporadic CJD. Aside from memory issues, visual loss, sensory abnormalities including incoordination, behavioural changes like agitation, anger, sadness, and mood swings can also happen.
Variant CJD (vCJD) affects young individuals, with a median illness duration of 13 to 14 months and a median age of death of 28. Psychiatric symptoms, behavioural abnormalities, and unpleasant dysesthesias are frequently its initial signs.
The time between the start of symptoms and death for neurological indications is longer than usual. Before the potential infectivity of these prions is determined, caution should be used when handling body fluids and tissues from patients with vCJD because prions have been found in the blood and urine of individuals with symptomatic vCJD.
Evaluation
Since it presents similarly to rapidly developing dementia, diagnosing Creutzfeldt-Jakob disease can be difficult for doctors.
Complete blood count (CBC), a basic metabolic panel with magnesium level, liver function tests, rapid plasma reagin, erythrocyte sedimentation rate, antinuclear antibody, C-reactive protein, thyroid function tests, vitamin B-12, HIV, Lyme disease titer, autoimmune antibodies, urinalysis, cerebrospinal (CSF) studies with glucose, oligoclonal bands, cell count and differential are all recommended as initial screening tests for evaluating rapidly progress Creutzfeldt-Jakob disease can be diagnosed using a combination of the clinical presentation and supporting diagnostic investigations.
The diagnostic criteria may need to be modified, nevertheless, in light of medical advancements and newer procedures like MRI, genetic testing, and other cutting-edge laboratory studies.
Brain MRI has been proven to be more sensitive and specific for vCJD than CSF 14-3-3 protein, and it is accurate in roughly 90% of cases. When sCJD is present, abnormalities in the deep nuclei and cortical grey matter are frequently seen on brain MRI using T2-weighted, diffusion-weighted imaging (DWI), and apparent diffusion coefficient (ADC) sequences.
The sensitivity and specificity of MRI with DWI/FLAIR imaging are 98% and 93%, respectively. The basal ganglia, thalamus, and cortex frequently exhibit hyper intensities during DWI. The "hockey stick" or "pulvinar" sign can appear in other types of CJD but is specific to variant (infectious acquired) CJD. Following typical EEG results in terms of sensitivity for CJD is CSF 14-3-3.
Treatment
CJD cannot be completely treated. Symptomatic and supportive care is the cornerstone of treatment. A few medication trials have been done by researchers for CJD, but none of them have so far demonstrated a definite advantage. To find a cure for this lethal illness, more study is required.
Prognosis
Despite all the improvements in our understanding of this illness, the prognosis is still rather dismal. CJD is always fatal. Death frequently happens one year after the onset of symptoms
Complications
The patient's brain and body are both profoundly affected by Creutzfeldt-Jakob disease, which also exhibits a quick progression. Patients with withdraw from loved ones frequently, eventually losing the ability to recognise or relate to them. They also lose the ability to care for themselves and frequently end up falling asleep. The fatality rate for CJD is 100%.
