CJD

Question 1

What is CJD

Answer 1

• Neurodegenerative condition that is caused by misfolded protein particles (prions)
• Cardinal features: rapidly progressive DEMENTIA + MYOCLONUS
• most patients die within 12 months of disease manifestation
• No cure

Question 2

Cause of CJD

Answer 2

• Sporadic: 85%
• Familial
• Acquired
  Iatrogenic due to medical procedures, eg: brain surgery, organ transplant, blood transfusion

Variant CJD - occurs due to ingestion of beef infected with bovine spongioform encephalopathy (BSE)

Question 3

Clinical features of CJD

Answer 3

• Prodromal: sleep disorders, headaches, fatigue
• Neurological: cerebellar disturbance (gait instability), myoclonus, ataxia, seizures
• Neuropsychiatric symptoms: rapidly progressive dementia

Main feature: RAPIDLY PROGRESSIVE DEMENTIA + MYOCLONUS

Question 4

Ix for CJD

Answer 4

• CSF: usually normal
• EEG: TRIPHASIC periodic sharp wave complexes with a frequency of 1-2Hz
• MRI: hyperintensity in basal ganglia, insular cortices, frontal cortices.
• Brain biopsy is diagnostic - spongiform degeneration (intracytoplasmic vacuoles within the neurons of cerebral and cerebellar cortex), gliosis, amyloid plaques

Question 5

Features of new variant CJD

Answer 5

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

• The typical presentation is that of a younger patient with progressive dementia (less rapid the sporadic CJD) with myoclonus and, in the later stages, mutism and vertical upgaze palsy (found in 50%).
• An MRI brain reveals a characteristic ‘hockey stick sign’ where the pulvinar region and dorsomedial thalamus are hyperintense on T2-weighted imaging (or pulvinar sign where the pulvinar region is hyperintense only). CSF protein for 14-3-3 and periodic sharp wave complexes on the EEG are more commonly seen in sporadic CJD.

Question 6

Other prion disease

Answer 6

Kuru
fatal familial insomnia
Gerstmann Straussler-Scheinker disease