Prion

Creutzfeldt-Jakob Disease

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Creutzfeldt-Jakob Disease, Jakob-Creutzfeldt Disease, Chronic Wasting Disease, Mad Cow Disease, New Variant CJD, Scrapie

  • Epidemiology
  1. Incidence of sporadic CJD: One case per million
  2. Age of onset
    1. CJD Mean age of onset: 68 (range: 55-75 years old)
    2. nvCJD: Young age of onset
  • Causes
  1. Sporadic Creutzfeldt-Jakob Disease
    1. Growth Hormone injections
    2. Corneal grafts
    3. Dural grafts
    4. Neurosurgical equipment
  2. nvCJD
    1. Eating contaminated beef (cattle fed sheep brain)
  3. Sheep CJD (Scrapie)
    1. Only transmitted to humans if passed via cattle
  4. Chronic Wasting Disease (passed by deer and elk)
    1. Broad range of positive cases in United States
      1. Identified in deer and elk in 1967
      2. Identified in deer and elk in 1980's
      3. Identified in Mt Horeb area: 14 per 500 deer
    2. Associated with captive elk on game farm (NE, MO, SD)
      1. Passed to free deer via salt licks, baiting
    3. CWD could theoretically be passed to cattle
    4. Signs in deer
      1. Muscle wasting
      2. Ataxia
      3. Difficulty swallowing Saliva
      4. Confusion
      5. Seizures
  • Pathophysiology
  1. Transmitted via prion protein infectious agents
    1. Only infectious agent to contain no nucleic acids
  2. Prions cause other proteins to precipitate
    1. Plaques of prion proteins form in brain
    2. Results in Spongiform encephalopathy
    3. Susceptible patients have polymorphism at codon 129
  3. Very difficult to control
    1. Resistant to disinfectants and sterilization
    2. Environmental decay is very slow
      1. Persists in environment despite removing animals
  4. Transmission
    1. Spread by Saliva
    2. Travels via lymph
    3. Spreads to brain via Lymphocytes
    4. Long latent period (from 2 to 40 years)
  • Variants
  1. Creutzfeldt-Jakob Disease (CJD)
  2. New Variant CJD (nvCJD)
  3. Bovine spongiform encephalopathy (Mad Cow Disease)
  4. Chronic Wasting Disease (CWD)
  • Signs and Symptoms
  1. Personality changes
  2. Ataxia
  3. Cerebellar signs
  4. Myoclonus
  5. Visual loss
  6. Extrapyramidal signs
  • Diagnostics
  1. EEG
    1. Slow wave background
    2. High voltage spikes
  2. MRI shows Pulvinar sign in nvCJD
    1. Zeider (2000) Lancet 355:1412 [PubMed]
  3. Brain Biopsy
    1. Amyloidosis
  4. Analysis of animal source
    1. Tonsil biopsy for prion protein
    2. CSF Protein analysis
  • Prevention of Chronic Wasting Disease
  1. Close deer and elk game farms in endemic areas
  2. Avoid deer and elk meat intake in endemic areas
  3. Do not dress deer in the field
  4. Know how meat is butchered
    1. Does butcher prepare deer or elk and beef?
  • Course
  1. Rapidly progressive
  • Prognosis
  1. Mortality approaches 100%
  • Management
  • Supportive (Only delays decline)
  1. Avoid Alcohol intake
  2. Consider anti-oxidant use
  3. Consider Tetracycline class antibiotics