Microbiology 9 - Prion disease Flashcards
What marker of sCJD may be identified in CSF?
14-3-3
What does ‘prion’ stand for?
PRotein-only InfectiOus ageNt.
What is the general pathophysiology of sporadic CJD?
Rapid neurodegeneration via spongiform vacuolation
Upon which chromosome is prion encoded?
C20
predominantly expressed in CNS
Describe the structure and function of healthy prion
Alpha helical structure - involved in copper binding
What is the structure of pathological prion?
Beta pleated sheet
What is the name given to sporadic prion disease?
sporadic Creutzfeld Jacob Disease
What are the acquired prion diseases?
- Variant - bovine spongiform encephalopathy
- iatrogenic CJD
- Kuru (Papau New Guinea)
What are the 3 causes of inherited CJD?
- PRNP mutations (can be inherited)
- Gertsmann-Strausser-Sheinker syndrome
- Familial fatal insomnia
How does sCJD present?
RAPID DEMENTIA with:
- myoclonus
- cortical blindness
- akinetic mutism
- LMN signs
What is the mean age of onset of sCJD?
45-75
How quickly does sCJD cause death?
Within 6/12 months
What is the mean age of presentation of variant CJD/ BSE?
30 years
What is the mean survival time in variant CJD?
14 months
**slightly longer than sporadic
Recall the typical presentation of variant CJD/ BSE
Dysphonia
Hallucinations
Anxiety
Paranoia
(Psychological symptoms mostly)
–>later neurological symptoms - peripheral sensory sx, ataxia, myoclonus
**think; younger population presenting w psychotic type symptoms, as opposed to older ppl presenting w dementia type symptoms**
What would an MRI show in variant CJD/ BSE?
Positive pulvinar sign
i.e. posterior thalamus highlighted on MRI-T2
What test is 100% sensitive and specific for variant CJD/ BSE, but useless in sporadic CJD?
Tonsilar biopsy – western blot –> type 4t
What is the inheritance pattern of prion proteins?
All autosomal dominant
What are the symptoms of Gertsmann-Strausser-Scheinher syndrome?
dysarthria progressing to cerebellar ataxia ending in dementia
sCJD EEG changes
periodic triphasic changes
MRI in sCJD
normal/highlighting basal ganglia
CSF analysis of sCJD
14-3-3 protein positive
Genetics of sCJD
most cases 129 codon MM
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