Creutzfeldt-Jakob disease

Creutzfeldt-Jakob Disease: description

Creutzfeldt-Jakob disease was first described in 1920 by neurologists Creutzfeld and Jakob. It is one of the so-called transmissible spongiform encephalopathies (TSEs). In these diseases, the brain tissue sponges loose, and the brain gradually loses its function.

Creutzfeldt-Jakob disease can occur in various forms. These include:

• Sporadic CJK (arises spontaneously for no apparent reason, is most common in 80 to 90 percent of cases)
• Family CJK (hereditary condition)
• Transmitted CJD (for example, the new variant of Creutzfeldt-Jakob Disease (vCJD))

Transmissible spongiform encephalopathies are not only known in humans but also in the animal kingdom. What they have in common is that they can easily skip species boundaries, for example from a sheep to a cattle or from a cattle to humans. For about 200 years, the TSE “scrapie” in sheep is known. In the 1990s, there were many cattle with bovine spongiform encephalopathy (BSE), especially in the UK. As a result of this epidemic, the new variant of Creutzfeldt-Jakob disease has been occurring in humans since 1996. To date, 219 cases of vCJD have been reported worldwide, including 175 patients from the UK. In Germany so far no case has been reported by vCJK.

In Germany, around 100 people a year suffer from a sporadic CJD. This number has remained the same for years and to be well identified, since both the suspicion of a Creutzfeldt-Jakob disease, as well as the death of it must be reported to the health department. Excluded are the family-related cases of the CJD.

Creutzfeldt-Jakob Disease: Symptoms

Creutzfeldt-Jakob disease manifests itself in a so-called encephalopathy – a collective term for diseases of the brain. It is mainly characterized by the following symptoms:

• Mental abnormalities (for example, depression, hallucinations, delusions, apathy, personality changes)
• Rapidly progressing dementia (with confusion, altered perception, difficulty concentrating)
• Uncoordinated movements (ataxia)
• Involuntary muscle twitching (myoclonus)
• sensory disturbances
• Incoordination
• Uncontrollable muscle movements (chorea)
• Muscle Stiffness (Rigor)
• blurred vision

The most important symptom of sporadic Creutzfeldt-Jakob disease is dementia. With the vCJK the psychic abnormalities prevail, the dementia occurs later in the course of the illness.

Creutzfeldt-Jakob Disease: Causes and Risk Factors

Creutzfeldt-Jakob Disease: Prions as triggers

Creutzfeldt-Jakob disease is caused by so-called prions. Prions are infectious protein particles (proteins) that resist most disinfection procedures. Even extreme heat or radioactive radiation can not harm them. Basically, prions are “mere proteins” and are much simpler in their structure than bacteria, viruses, fungi or parasites that cause most infectious diseases. Prions have only been known as pathogens for some years and have not been exhaustively researched. Scientists suggest that prions are created by misfolding a normal protein and adopting a new structure. This protein, in turn, causes other proteins to also form defective structures. In this way, many misfolded proteins accumulate in the body and are deposited mainly in nerve cells. The nerve cells are damaged and are destroyed and a spongy loosening of the brain develops.

Creutzfeldt-Jakob Disease: Genesis of the Prions

The expression of Creutzfeldt-Jakob disease is caused by different prions. For the sporadic CJK, nothing is known yet about the exact mechanism of prion formation.

The familial Creutzfeldt-Jakob disease arises due to a faulty genetic information. A mutation in the genetic material causes proteins to be assembled incorrectly and prions to emerge. So far, over 30 different mutations are known. They are all inherited as autosomal dominant. This means that this genetic information prevails over another and only one parent must carry the faulty gene in itself, so that the child is ill.

Creutzfeldt-Jakob disease is transmitted in various ways. For example, it may be transferred to a patient during operations through contaminated neurosurgical surgical instruments or blood transfusions. Also, a corneal transplantation on the eye or a transplantation of hard meninges (Dura mater) infection is possible if the donor suffered from Creutzfeldt-Jakob disease. Earlier growth hormones from the pituitary gland of corpses were used for therapy. Here, too, Creutzfeldt-Jakob disease was transmitted.

Only a few years ago tribes in New Guinea used the habit of ritually eating the brain of the dead. As a result, the disease (Kuru disease) spread there strongly. And the new variant of Creutzfeldt-Jakob disease is also a transmitted form. The cause is most likely BSE contaminated beef consumed by patients.

Creutzfeldt-Jakob Disease: BSE

Everything important to Creutzfeldt-Jakob disease: BSE read in the article BSE.

Creutzfeldt-Jakob Disease: How to protect yourself?

In order to protect yourself from Creutzfeldt-Jakob disease, you should refrain from beef products made from nerve tissue such as bovine brain. In addition, the feeding of animal meal to livestock species has been banned in order to minimize the possibility of risk material entering the human food chain. Milk and dairy products are risk-free. Since the onset of the BSE epidemic in the 1990s, Germany has had a BSE test for slaughtered cattle. Since 2015, this test for healthy cattle has been abolished. A vaccine against the disease does not exist so far.

Creutzfeldt-Jakob Disease: Investigations and Diagnosis

The diagnosis of Creutzfeldt-Jakob disease is mainly due to clinical symptoms. Before the physical examination, the doctor will ask you the following questions, among other things, in order to record the history of the disease (anamnesis):

• What day is today?
• Where are you?
• Are you content?
• Did a relative of yours suffer from Creutzfeldt-Jakob disease?
• Did you receive a corneal transplant?

Creutzfeldt-Jakob Disease: Investigation

Your doctor then examines you physically and tests the functioning of the nervous system. These include coordination exercises or force measurements as well as the examination of reflexes and touch perception.

Nervous water (cerebrospinal fluid) is often obtained with a lumbar puncture. This flows around the brain and spinal cord and may contain indications of possible causes of illness. The doctor penetrates a cannula under local anesthesia on the lower back of the sitting patient and pushes it to the so-called spinal canal, where the spinal cord is surrounded by cerebrospinal fluid. If the patient suffers from Creutzfeldt-Jakob disease, in many cases elevated levels of certain proteins are found, such as the proteins “14-3-3” or “tau”. This is not the case with the vCJK.

In addition, the physician can derive the brain waves with an electroencephalography (EEG). For this purpose, the patient electrodes are attached to the head. A device records the electrical activity in the brain. Creutzfeldt-Jakob disease shows specific changes in the EEG about twelve weeks after onset of the disease. In vCJD, these changes rarely occur.

Magnetic resonance imaging (MRI) is used to visualize the spongy loosening and shrinking of the brain. In addition, changes indicative of potential protein deposits can be detected in certain areas of the brain (often in the basal ganglia).

Creutzfeldt-Jakob Disease: autopsy

Creutzfeldt-Jakob disease can only be confirmed after the death of the patient. The pathologist extracts tissue samples from the brain and examines them under the microscope after staining the protein deposits in the nerve cells with dyes. In about one third of the patients, prions are also found in the spleen and in muscles.

Creutzfeldt-Jakob Disease: Treatment

A therapy that addresses the causes of Creutzfeldt-Jacob disease, there is not yet. Therefore, the doctor specifically treats the individual symptoms as part of a so-called symptomatic therapy. Research is currently being conducted on medicines that can cure the disease.

Anticonvulsants may prescribe the doctor in muscle twitching. These medications are also used in the treatment of seizures. In Creutzfeldt-Jakob disease, especially the active ingredients clonazepam and valproic acid are used. Antidepressants are also used in depression, so-called neuroleptics in hallucinations and restlessness.

Creutzfeldt-Jakob Disease: Disease course and prognosis

The Creutzfeldt-Jakob disease is not curable and ends after a short time always deadly. How long it takes after the infection, until the disease breaks out (incubation period), is not yet finally resolved. It is believed that it can take years to decades.

Depending on which form of Creutzfeldt-Jakob disease the patient suffers, the course is different. The sporadic form usually occurs between the age of 60 and 70 and progresses rapidly. It usually leads to death within six months. The family-related Creutzfeldt-Jakob disease runs a little slower and begins around the age of 50 already. At the vCJK, patients get sick much earlier, before the age of 30. The new variant of the Creutzfeldt-Jakob disease lasts longer and ends fatally after about twelve to 14 months.