Introduction

Creutzfeldt-Jakob disease (CJD) is rapidly progressive neurological condition caused by prion proteins. These proteins induce the formation of amyloid folds resulting in tightly packed beta-pleated sheets resistant to proteases.

Classification

Sporadic CJD
  • accounts for 85% of cases
  • 10-15% of cases are familial
  • mean age of onset is 65 years

New variant CJD
  • younger patients (average age of onset = 25 years)
  • psychological symptoms such as anxiety, withdrawal and dysphonia are the most common presenting features
  • the 'prion protein' is encoded on chromosome 20 - it's role is not yet understood
  • methionine homozygosity at codon 129 of the prion protein is a risk factor for developing CJD - all patients who have so far died have had this
  • median survival = 13 months

Other prion diseases
  • kuru
  • fatal familial insomnia
  • Gerstmann Straussler-Scheinker disease

Epidemiology

  • Incidence: 0.10 cases per 100,000 person-years
  • Peak incidence: 50-60 years
  • Sex ratio: 1:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

Features

Investigations

Investigation
  • CSF is usually normal
  • EEG: biphasic, high amplitude sharp waves (only in sporadic CJD)
  • MRI: hyperintense signals in the basal ganglia and thalamus