Creutzfeldt-Jakob Disease

Creutzfeldt-Jakob Disease (CJD), named after the German doctors Hans Gerhard Creutzfeldt and Alfons Maria Jakob, is considered the main manifestation of transmissible spongiform encephalopathy or prion diseases (Porter & Leemans, 2013). CJD is also known as mad cow disease. Prions, or proteinaceous infectious particles, are the direct agents of the disease. It occurs when prion protein takes a three-dimensional shape. This abnormal protein transforms a healthy protein of human body into the same shape; thus, there is an infection. Scientists have not explored this process in details yet; however, it is known that a misfolded prion protein destroys brain cells. Creutzfeldt-Jakob Disease makes up about 85% of all cases of human prion encephalopathy (Song & Zhang, 2015). CJD is rare as about one in a million is infected annually throughout the world (Song & Zhang, 2015). This paper aims to explore the forms of Creutzfeldt-Jakob Disease, their symptoms, diagnosis, prophylactic measures, and possible treatment.

Forms of CJD and Their Symptoms

There are four forms of CJD: spontaneous or sporadic, genetic, iatrogenic, and variant Creutzfeldt-Jakob Disease. According to modern investigations, in case of spontaneous or sporadic CJD, prions occur in the brain spontaneously without any apparent external cause (Ebringer, 2015). The disease usually affects people over the age of 50. First, it appears in the form of brief memory loss, mood changes, and loss of interest. In the final phase, vision and speech disorders as well as hallucinations occur. Genetic CJD occurs in the families with inherited gene for the prion protein damage. A defective prion protein is much more susceptible to spontaneous transformation into a prion. Iatrogenic CJD is the form of the disease that can happen after casual insertion of prions into a human’s body, for example, during a brain operation. Today, this source of contamination is eliminated. These three forms are characterized by behavioral disorders, disorders of higher cortical functions, cerebellar dysfunction, a combination of pyramidal and extrapyramidal symptoms, and myoclonic seizures. In the terminal phase, the global cognitive impairment, fatal in 8 months from the onset of the disease, occurs (Ebringer, 2015).

Variant CJD first appeared in 1995 in the UK, and since that time, more than 100 people had died; they were infected by meat products containing bovine spongiform encephalopathy prions (Ebringer, 2015). In contrast to the classical form of CJD, this form affects both young and old people. It is characterized by the loss of interest, depression, weight loss, and poor coordination of movements; the patient does not observe the basic rules of hygiene, cannot eat without help. Brain damage increasingly breaks basic life functions, and finally, the patient dies. In contrast to the classical form of the disease, the patient suffering from variant form is long conscious and he or she understands the worsening condition. The main characteristics of variant CJD are mental disorders and sensory impairments, global cognitive impairment and ataxia, possible cortical blindness, known as Heidenhain syndrome, episyndrome, presented as myoclonic seizures, and cerebellar symptoms.

The Diagnosis of Creutzfeldt-Jakob Disease

The diagnosis of Creutzfeldt-Jakob Disease is the allocation of the classic symptoms of it – progressive dementia, which means the rapidly growing intellectual and behavioral disorders in combination with myoclonia. From paraclinical disease diagnostic methods, the following tests are considered the most informative ones. The first test is electroencephalography. In patients with CJD, characteristic disturbances in the EEG are detected. Sporadic Creutzfeldt-Jakob Disease is characterized by the three-phase detection of EEG activity; early paroxysmal activity is usually diagnosed after 12 weeks from the beginning of sporadic CJD in 80-88% of patients (De Villemeur, 2012).

The second effective method is magnetic resonance imaging. This technique relies on the use of strong magnetic fields to create detailed images of internal organs. MRI is particularly useful in the diagnosis of brain diseases, because it allows getting a good image of white and gray matter of the brain. The characteristic data of MRI of the brain can detect the signs of atrophy of the cerebral cortex and cerebellum.

According to the third method, the analysis of the cerebrospinal fluid should be taken. It is necessary to make a lumbar puncture to get some milliliters of the material. The presence of a certain protein in the cerebrospinal fluid is a sign of Creutzfeldt-Jakob Disease. Cerebrospinal fluid pressure must be taken into account, as well as blood sugar levels, cell counting, the presence of bacterial and viral cultures, and cryptococcal antigen. A slight increase in protein levels can be observed (De Villemeur, 2012).

The fourth possible method of the diagnosis is the biopsy of tonsils as they are able to accumulate the evidence of prion infection. The study of tissue samples, taken by biopsy, helps to diagnose mad cow disease, but this method is considered less reliable than others. If the diagnosis is unclear, it is possible to conduct a lifetime brain biopsy in the presence of a consent from relatives or guardians in the case of incapacity of the patient. Morphological and histological examination of brain tissue such as cortex and subcortical nuclei are possible at autopsy (De Villemeur, 2012).

Prophylactic Measures and Treatment of Creutzfeldt-Jakob Disease

When it comes to prophylactic measures, the medical employees, who are in contact with body fluids and tissues of patients with suspected Creutzfeldt-Jakob Disease, should wear gloves and avoid contact with infected material with mucous membranes. After the contact of infected material with the skin, first of all, skin disinfection with 4% sodium hydroxide must be conducted for 5-10 minutes; then, skin should be washed under running water. For the decontamination of materials and tools, autoclaving at 132 ° C for 1 hour or sterilization in 4% sodium hydroxide or 10% sodium hypochlorite solution for 1 hour are recommended (De Villemeur, 2012).

In 2003, British doctors conducted an experimental treatment of 19-year-old Irish boy Jonathan Simms, suffering from Creutzfeldt-Jakob Disease. They used a new experimental medicine— pentosan polysulfate (PPS). This medicine did not cure the disease and did not stop the destructive processes, but the patient’s condition improved significantly after treatment. Thus, pentosan polysulfate, even if unable to cure patients, stops the progression of the disease, thereby increasing the longevity or even improving their condition. After injection, swallowing reflex returned; moreover, the patient lived for almost 8 years after this treatment. Pentosan polysulfate is intended for intraventricular administration, allowing the quick delivery of the desired concentration of the active ingredient directly into the brain tissue. Oral or parenteral administration of the medicine has no appreciable effect. Among the side effects, in some cases, it may cause nausea, vomiting, a slight anemia, and in rare cases, the development of severe thrombocytopenia (Song & Zhang, 2015).

In identifying CJD, all medical treatments, which may adversely affect the mnemonic function and the patient’s behavior, should be canceled. Conventional antiviral agents, such as amantadine, interferons, vaccination, and passive immunization of humans and animals, have proved to be ineffective (Porter & Leemans, 2013). Symptomatic treatment is aimed at a relief of myoclonic seizures and extrapyramidal disorders; therefore, antiepileptic and antiparkinsonian medicines are used with the purpose of preventing and reducing the frequency and intensity of seizures or their equivalents: the loss or impairment of consciousness, behavioral and autonomic dysfunction. They reduce extrapyramidal disorders and tremor. Although an effective treatment for cure mad cow disease is absent, such medicine as Brefeldin A and calcium channel blockers have positive affect on the process. Brefeldin A is given to the patient in order to avert the synthesis of PrPSc in infected cells by destroying the Golgi apparatus. It is a known irreversible inhibitor of translocation of proteins from the endoplasmic reticulum to the Golgi apparatus. It blocks the cytotoxicity of conditioned medium, assuming that cytotoxic proteins are exported via Golgi apparatus (Porter & Leemans, 2013). Calcium channel blockers, particularly NMDA-receptors, are given to promote the long-term survival of the infected neuronal culture (Porter & Leemans, 2013).

Conclusion

Creutzfeldt-Jakob Disease belongs to the group of transmissible neurodegenerative prion diseases. It is a progressive dystrophic disease of the cerebral cortex, spinal cord, and basal ganglia. It leads to the problems with thinking, muscle movements, and causes fatal outcome. There are four forms of this rare disease and enough methods of CJD diagnosis, but in any case, the results of a brain biopsy always have the final word. Unfortunately, only symptomatic treatment can be provided. Many potential therapeutic interventions for CJD are currently at the discussion level. The scientists have to admit that etiotropic treatment of Creutzfeldt-Jakob Disease has not been found yet.

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