Spongiform Encephalopathy / Creutzfeldt-Jakob Disease

Overview

Snapshot

• A 58-year-old male presents with difficulties in concentration and worsening insomnia. These symptoms have been progressively worsening over the past month. Startle myoclonus is appreciated on physical examination. Electroencephalography shows biphasic sharp wave patterns.

Introduction

• Prions
  • misfolded intracellular proteins that lead to neurodegeneration
    • PrP^c (normal; α-helix isoform) undergoes conformational change into PrP^sc (abnormal; β-pleated sheet isoform) 
      • PrP^sc is resistant to intracellular proteases
        • can further induce PrP^c into PrP^sc → cytoplasmic vacuoles and neuronal death
• Spongiform encephalopathy
  • Creutzfeld-Jakob disease (CJD)
    • most common
    • can be sporadic, familial or acquired
• acquired via iatrogenic or dietary methods

Presentation

• Symptoms
  • rapidly progressive dementia
    • occurs in weeks to months
  • myoclonus
    • startling the patient can induce myoclonus
  • ataxia
  • distrubances in vision
• e.g., visual field defects, abnormalities in perception

Evaluation

• Histology
  • spongiform cortex
    • large intracellular vacuoles 
• Electroencephalography
  • spike (sharp) wave pattern
• Cerebral spinal fluid (CSF)
  • 14-3-3 protein
• Magnetic resonance imaging
• hyperintensity in the head of the caudate and putamen on T2-weighted and FLAIR images

Differential

• Alzheimer disease
• Frontotemporal dementia
• Vascular dementia
• HIV-associated dementia

Treatment

• Supportive
• No effective treatment

Prognosis, Prevention, and Complications

• Prognosis
  • death typically within 1 year of symptom onset
• Prevention
  • iatrogenic
    • screen dura mater and cornea donors
    • incinerate medical tools used in patients with/suspective of CJD
    • recombinant human growth hormone use instead of human derived
• Complications
  • seizures
  • aspiration pneumonia