MI: Prion Disease Pt.2 Flashcards
Describe the histological appearance of CJD.
Spongiform vacuolisation
NOTE: there are amyloid plaques but these are different from the plaques seen in Alzheimer’s disease
List the differential diagnosis for CJD.
- Alzheimer’s disease
- Vascular dementia
- Mixed dementia (AD + vascular)
- CNS neoplasms
- Cerebral vasculitis
- Paraneoplastic syndromes
- Other CJD types (familial, variant)
What is variant CJD?
CJD in younger people that has resulted from the BSE epidemic
What animal disease is vCJD linked to?
Bovine spongiform encephalopathy (Mad cow disease)
Describe the epidemiology and clinical features of vCJD
- Younger age of onset - median age 26 years
- Median survival 14 months
- Psychiatric onset - dysphoria, anxiety, delusions, hallucinations
- Followed by neurological symptoms - peripheral sensory symptoms, ataxia, myoclonus, chorea, dementia
What is a characteristic MRI feature of vCJD?
Pulvinar sign - bilateral hyperintensity in the posterior thalamus
Hockey stick sign
How is the use of CSF markers different in vCJD?
14-3-3 and S100 are NOT useful in vCJD diagnosis
Which investigation is most useful for vCJD?
Tonsillar biopsy
- Prions localise in lymphoid tissue
- Type 4t
- 100% sensitive and specific
- May be positive during incubation period before symptom onset
NOTE: this is not useful in sCJD
Describe the role of neurogenetics in vCJD.
Almost 100% of patients are MM at codon 129 (in the PRNP gene)
List some causes of iatrogenic CJD.
- Human cadaveric growth hormone
- Corneal transplants
- Neurosurgical procedures e.g. dural grafts (pre-1991)
- Blood transfusions
Outline the clinical features of iatrogenic CJD.
- Starts with progressive ataxia
- Dementia and myoclonus occur at a later stage
Speed of symptom progession in iatrogenic CJD depends on route of innoculation (CNS innoculation is fastest)
What is the inheritance pattern of inherited prion disease?
Autosomal dominant
Which specific polymorphism in the PRNP gene is significant in inheried prion disease
MM (methionine-methionine) polymorphism at codon 129
(may confer earlier onset)
What are some alternative diagnoses for someone presenting with features suggestive of prion disease?
- Spinocerebellar ataxia
- Huntington’s disease
What is crucial to ask in the history when assessing inherited prion diseases?
Family history