Microbiology 5: Prion Diseases Flashcards
Which test detects active syphilis ?
RPR (Rapid plasma reagin)
can also send VDRL
Which protein is a marker of rapid neurodegeneration ?
14-3-3
What is the difference between PrP and PrP^sc ?
PrP is the normal prion protein found in the body. It forms alpha helical configurations and is soluble.
PrP^sc is the pathological prion protein seen in prion diseases. It forms beta pleated sheets which are insoluble and deposit in the brain. PrP^sc acts as a template causing rapid conversion of normal PrP to PrP^sc
Name a sporadic prion disease ?
Creutzfeldt-Jakob disease (CJD)
Name an acquired Prion disease ?
Kuru
Variant CJD
Iatrogenic CJD
Name a genetically acquired prion disease ?
Gerstmann-straussler-sheinker syndrome (GSSS)
Familial fatal insomnia
List 4 signs of CJD ?
Dementia
Myoclonus
Cortical blindness
Akinetic mutism (loses ability to speak and mobilise)
Which EEG finding which may suggest sporadic CJD ?
Periodic triphasic complexes
What is the characteristic histological finding in CJD ?
Spongiform vacuolisation
Which symptoms are seen in variant CJD that are not seen in sporadic CJD ?
Psychiatric signs: hallucinations, dysphoria, anxiety
Peripheral sensory changes
Typically affects younger p(- 30 yrs)
What is the characteristic MRI sign for variant CJD ?
Pulvinar sign (high signal in the putamen)
What is the diagnostic test for variant CJD ?
Tonsillar biopsy
List features of Sporadic CJD ?
4LAMB
- 4 months to live after onset of rapidly deteriorating dementia
- Lower motor neurone signs
- Akinetic mutism
- Myoclonus
- Cortical blindness
what does an increased signal in the cortex of the R parietal lobe on diffusion-weighted MRI suggest
CJD
what are prion diseases
protein-only infectious diseases
transmissible spongiform encephalopathies in humans and animals
leads to development of spongiform vacuolisation of the brain
rapid neurodegeneration
untreatable
where is prion protein encoded
chromosome 20 on codon 129 there are 3 polymorphisms MM - predisposes to prion disease MV VV
features of sporadic CJD
rapid dementia + myoclonus, cortical blindness, akinetic mutism, LMN signs cause uncertain EEG - triphasic complexes (abnormal) MRI - increased signal in basal ganglia CSF - raised protein 14-3-3 and S100 histology - spongiform vacuolisation
describe the presentation of vCJD
psychiatric onset
followed by neurological symptoms - peripheral sensory, ataxia, myoclonus, chorea, dementia
diagnosis of vCJD
MRI - pulvinar sign (high intensity in the putamen)
EEG - non-specific slow waves
TONSIL BIOPSY - 100% sensitive and specific
histology - accumulated plaques
some areas of vacuolisation
list causes of iatrogenic CJD
human cadaveric GH corneal transplants neurosurgical procedures blood transfusions * no blood test for CJD
features of familial prion disease
AD mutations
non specific EEG
neurogenetics is crucial
what is GSSS
presents as slowly progressing ataxia
diminished reflexes
dementia
PRNP P102L mutation most common
what is familial fatal insomnia
untreatable insomnia
dysautomnia
ataxia
PNRP D178N
what can e used for treatment of CJD
symptomatic - clonazepam, valproate
delaying prion conversion - quincarine, pentosan, tetracycline
anti-prion antibody - blocks progression to disease
