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Introduction ⬇

Prions are proteins that occur in both heredity forms and infectious disease. Prions do not contain RNA or DNA. No immune response has been detected. This test is done to diagnose prion brain disease, such as Creutzfeldt–Jakob disease and bovine spongiform encephalitis (mad cow disease). The structure and dynamics of proteins become somewhat problematic when developing anti-based diagnostic tests. This is particularly relevant in the case of diagnostic tests for prion diseases. As an example, prion diseases of the CNS are a result of conformational changes in the prion protein. The scrapie prion protein (PrPSc), which is the lethal form, is chemically indistinguishable from the normal cellular prion protein (PrPC). The conversion from PrPC to the lethal PrPSc form has been under investigation, and several mechanisms have been proposed, such as spontaneous conversion or assisted conversion.

Normal Findings ⬆ ⬇

Procedure ⬆ ⬇

  1. Brain tissue samples are examined for evidence of the infectious prion or mutated gene in chromosome 20.

Clinical Implications ⬆ ⬇

  1. Abnormal finding of PrPSc protein (disease-causing form) is pathogenic, which affects the cerebral cortex and cerebellum.

  2. Gerstmann–Sträussler–Scheinker syndrome, a cause of hereditary dementia, occurs because of mutation in prion gene.

  3. Fatal familial insomnia.

  4. Creutzfeldt–Jakob disease.

  5. Evidence of prion infectious disease may be transfusion-related.

Interventions ⬆

Pretest Patient Care

  1. Explain test purpose and procedure. Obtain from patient or family signs, symptoms, and history of encephalopathy or dementia (hereditary). Patients are usually very sick, and infectious disease is usually fatal.

  2. Behavioral changes include ataxia, peripheral sensory changes, and dementia.

Posttest Patient Care

  1. Review test results; report and record findings. Modify the nursing care plan as needed. Counsel the patient regarding abnormal findings; explain the need for possible follow-up testing and treatment. Monitor for encephalitis and dementia.

  2. Provide comfort and support and special counseling regarding progression of disease. Death occurs about 12 months after appearance of first signs.