17.7 Dementia and Degenerative Disorders Flashcards
Degeneration in what area of the brain will lead to movement problems?
Basal Ganglia - sometimes in the brainstem
What does degeneration of the cortex cause?
Dementia
Alzheimer’s Disease
Degenerative disease of the cortex
What is the most common cause of dementia?
Alzheimer’s Disease
The deposition of ______ leads to Alzheimer’s disease?
Aß-amyloid - cleaved form of amyloid precursor protein
What are the clinical features of Alzheimer’s disease?
- Slow memory loss
- Progressive disorientation
- Loss of learned motor skills
- Personality changes
- NO early focal neurologic deficits
Most cases of Alzheimer’s are ______
Sporadic
What is a genetic risk factor of Alzheimer’s?
Epsilon4-ApoE
What is a genetic decreased risk factor of Alzheimer’s?
Epsilon2-ApoE
What gene mutation is early onset Alzheimer’s associated with?
Presenlin-1 and 2
What is Alzheimer’s associated with?
Down Syndrome - amyloid precursor is found on Ch21 so there is increased Aß-amyloid
What will be seen on the brain of an Alzheimer’s patient?
Diffuse cortical atrophy - with narrowing of the gyri and widening of the sulci
Hydrocephalus Ex Vacuo
Consequence of brain atrophy where the ventricles of the CNS dilate
Cerebral Amyloid Angiopathy
Deposition of Aß-amyloid into the blood vessels of the brain
What protein is present in neurofibrillary tangles?
Tau Protein that is hyperphosphorylated
Vascular Dementia
Multifocal infarction and injury that can be due to HTN, atherosclerosis or vasculitis that decreases blood flow to brain
What is the second most common cause of dementia?
Vascular Dementia
Pick Disease
Degenerative disease of the frontal and temporal lobe that spares the parietal and occipital lobes - leads to behavioral and language symptoms
What is found in Pick disease?
Round aggregates of tau protein in neurons of the cortex
Parkinson Disease
Degenerative loss of dopaminergic neurons in the substantia nigra (pars compacta)
What is the effect of dopamine from the substantia nigra - pars compacta on the striatum?
- Increases stimulation with D1 receptor binding
- Decreases inhibition with D2 receptor binding
Overall increases cortical function and increases movement
Exposure to what chemical has been known to lead to Parkinson’s?
MPTP
What are the clinical features of Parkinson’s?
Tremor
Rigidity
Akinesia
Postural Instability
What are the round eosinophilic bodies seen in Parkinson’s?
Lewy Bodies
What are Lewy Bodies composed of?
Alpha synuclein
What does early dementia in Parkinson’s suggest?
Lewi Body Dementia - Lewy bodies in the cortex
Huntington’s Disease
Degeneration of the GABAergic neurons in the caudate nucleus of the basal ganglia
What is the function of the caudate?
The GABA neurons of the caudate send inhibitory signals to the cortex.
What is a main feature of Huntington’s?
Chorea
What is the inheritance pattern of Huntington’s?
Autosomal Dominant
What is the mutation seen in Huntington’s?
CAG repeats in the huntingtin gene
What is a common cause of death with Huntington’s?
Suicide
Normal Pressure Hydrocephalus
Increased CSF results in dilated ventricles and can cause dementia
What are the clinical features of normal pressure hydrocephalus?
- Urinary incontinence
- Gait instability
- Dementia
What is the treatment for normal pressure hydrocephalus?
Ventricle-Peritoneum Shunt
Spongiform Encephalopathy
Degenerative disease due to a prion protein
What is the pathologic protein in spongiform encephalopathy?
Prp c in a beta-pleated sheet configuration that is non-degradable
What is the hallmark of spongiform encephalopathy?
Intracellular vacuoles in neurons and glial cells
What are the 3 mechanisms for spongiform encephalopathy?
- Sporadic
- Inherited
- Transmitted
Creutzfeldt–Jakob Disease (CJD)
Usually sporadic that can rarely arise form exposure to prion infected human tissue and presents as rapidly progressive dementia associated with ataxia and startle myoclonus - fatal within 1 year
vCJD
Related to exposure to bovine spongiform encephalopathy
Familial Fatal Insomnia
Inherited prion disease characterized by insomnia and an exaggerated startle response