Degenerative Diseases Flashcards
T or F: The proportion of change of Alzheimer pathologic change decreases continuously from age 70 to age 100
T
What percentage of AD patients have a dominant inheritance pattern?
<1%
High degree of penetrance
What is the Ribot law of memory?
The remote memories are preserved while the recent ones are lost
T or F in the late stages of AD the patient is left in a state of paraplegia in extension
F. In flexion.
What % of patients in the late stages of AD develop seizures?
5
What are the five main symptomatologies un AD?
Which one is the most prominent?
Amnesia-- MOST PROMINENT Naming Paranoia and personality changes Executive function Visuospatial orientation
Microscopically early in the disease loss of nerve cells is seen where?
What lobes are usually involved in Alzheimer’s disease?
Layer 2 of the entorhinal cortex
Frontal, temporal and parietal–
Most affected: hippocampus, parahippocampus and subiculum
What are the 3 pathological hallmarks of AD?
- Neurofibrillary tangles (hyperphosphorylated form of the microtubular protein tau)
- Amyloid spherical deposits seen with PAS stating (neuritic plaques)
- Granulovacuolar degeneration of neurons in the pyramidal layer of the hippocampus
What particular part of the hippocampus is affected in AD?
What do astrocytes look like in AD?
CA1 and CA2 (of Lorente de No)
Compensatory hypertrophy is seen most in layer 3 and 4
What is tau composed of? what does it form?
beta 2 transferrin –> tau –> tangles
Tau is a discrete cytoskeleltal protein that promotes assembly of the microtubules and stabilizes their structure
What sequence of events favor amyloid toxicity?
Amyloid precursor protein (APP)–> cleaved by beta then by gamma –> Abeta 40 (non toxic) AND Abeta42 (toxic) protein favors fibrillogenesis; amyloid aggregation–> neuronal toxicity
Non toxic route is cleavage by alpha secretase cleavage followed by gamma cleavage
The cholinergic synthetic capacity of demented brains is decreased on account of reduction in cells in?
Basal forebrain nuclei or nucleus basalis of Meynert
What chromosome is the errant amyloid precursor protein seen? How about mutated presenellin genes?
Chromosome 21
Chromosome 14 and 1
T or F. Apo E a regulator of lipid metabolism in its E4 isoform doubles the risk of developing SPORADIC AD.
F. triples the risk!
having 2 e4 alleles guarantees the development of AD if the individual lives until 80
e4 actas a SUSCEPTIBILITY RISK FACTOR– it accelerates the appearance of AD by about 5 years
What 3 genes are responsible for early AD?
APP, PS1, PS2
What is the EEG and CSF in AD?
Late in the disease diffuse slowing on EEG
Occasionally elevated protein
Which areas exhibit diminished activity with SPECT (blood flow) and PET (metabolism) in AD?
- Medial temporal lobes
2. Parietal association regions
T or F the ratio of A beta 42 to tau is IN THE CSF is LOW in AD
What areas in neuropsychologic testing do patients with AD score low in?
T
Memory and verbal access skills
What is the CNS disorder usually seen in the context of alcoholism and malnutrition. The condition classically involves the corpus callosum with necrosis and demyelination.
What are the 3 types of FTLD?
Marchiafava-Bignami disease
- Behavioural variant (frontal lobe involvement)
- The language variant (left frontal or temporal lobe involvement) presenting with apraxia and aphasia
- Posterior cortical atrophy: Progressive loss of the ability to understand and use visual information with relative sparing of memory
T or F. Amyloid plaques and tangle deposition are far more common in the brains of patients with PD 20-30% than in AD
In FTD what are argyrophilic cytoplasmic inclusions called? Diffusely staining ballooned cells?
T
Pick bodies
Pick cells
What percentage of Primary Progressive Aphasias (FTD variant) have Pick bodies? Have AD histopath?
40-40
60% HAVE NO CHARACTERISTIC PATHOLOGIC CHANGE
What are the two types of primary progressive aphasia (a variant of FTLD)?
What are the main components of lewy bodies?
Progressive nonfluent aphasia: Characterized by decreased verbal output and difficulty finding words but the language system is intact
Semantic dementia: The patient retains fluency. Initial sxs characterized by difficulty naming and generating a list of words.
Logopenic aphasia
ubiquitin and synuclein
What is the essential criteria for DLB diagnosis?
What are the 4 core clinical criteria for DLB?
What are the indicative biomarkers?
CRITERIA:
Probable DLB can be diagnosed if:
a. Two or more core clinical features of DLB are present, with or without the presence of
INDICATIVE biomarkers, or
b. Only one core clinical feature is present, but with one or more indicative biomarkers.
Probable DLB should not be diagnosed on the basis of biomarkers alone.
Supportive biomarkers include: Generalized low uptake on SPECT/PET perfusion/metabolism scan with reduced occipital
activity 6 the cingulate island sign on FDG-PET imaging.
ESSENTIAL CRITERIA: Progressive cognitive decline sufficient magnitude to interfere with normal social and occupational function
CLINICAL
1. Fluctuating cognition with pronounced variations in attention and alertness.
2. Recurrent visual hallucinations that are typically well formed and detailed.
3. REM sleep behavior disorder, which may precede cognitive decline.
4. One or more spontaneous cardinal features of parkinsonism: these are bradykinesia (defined as
slowness of movement and decrement in amplitude or speed), rest tremor, or rigidity.
BIOMARKERS
- Reduced dopamine transporter uptake in basal ganglia demonstrated by SPECT or PET.
- Abnormal (low uptake) 123iodine-MIBG myocardial scintigraphy.
- Polysomnographic confirmation of REM sleep without atonia.
What drug reduces delusions, hallucinations and anxiety for lewy body dementia?
Rivastigmine
What is the triad of Huntington disease?
- Dominant inheritance
- Choreoathethosis
- Dementia
Identify which gene:
- Huntington
- Alzheimer’s disease
- Chromosome 4, CAG repeats
2. Chromosome 21
What is the critical number of CAG repeats before Huntington symptoms invariably manifest?
What number for a late onset mild form of the disease “senile chorea”?
More than 42
35-39
at 39 to 42 disease may not manifest if the person does not live long enough
T or F. In Huntington dementia, there is relative sparing of memory, aphasia, agnosia apraxia because it is a “subcortical dementia”.
T
Inability to manage household, diminished work performance, difficulty with concentration and assimilating new material
In huntington chorea, what comes first? cognitive impairmaent or movement disorder
How to distinguish from PD on the basis of blink rate?
Cognitive impairment
High blink rate in HD low in PD
What is the characteristic pathology of the brain of HD patients?
What is the Westphal variant of HD?
Atrophy of the head of the caudate and putamen + also of the frontal and temporal regions
Westphal– rigid variant with mostly parkinsonism sxs
Why does expansion the polyglutamine portion of huntingtin result in neuronal loss?
How long before HD patients become vegetative?
Makes the cells undult sensitive to glumate induced toxicity
10-15 years of symptoms
What drug can be used for huntington?
What are the finding sin neuroimaging of HD?
Dopamine antagonist, haloperidol
Gross bilateral atrophy of the caudate nucleus and putamen with diffusely enlarged ventricles
What is the usual blink rate?
Normal is 12-20
in parki it is less than normal 5-10
in huntington it is more than normal
What are the 2 common tremors of PD?
- 4 per second pill rolling tremor of the thumb, tremor in a position of repose
- 7-8 per second slighly irregular action tremor of the outstretched finger and hands that PERSISTS throughout voluntary movement and on outstretched fingers and hands NOT present in the resting position
What is the froment sign?
What are the 4 core features of Parkinson disease?
Rigidity is elicited by having the opposite hand engage in a motor activity that require concentration– like touching each finger to the thumb on the opposite limb
BRIT
Bradykinesia, Rigidity, Instability of Posture, Tremors
What is camptocormia?
What is kinesis paradoxica?
Extreme forward flexion of the spine and corresponding severe stooping occurs
Remarkably effective movement during unusual circumstances (danger) in usually bradykinetic and rigid PD patients
What is the myerson sign?
What is the average time before PD patients acquire dyskinesia from mediation use?
inability to inhibit blinking as a response to a tap over the bridge of the nose or glabella
3-5 years
What is the average time in PD from inception of the disease to a chairbound state?
7.5 years BUT THIS HAS A WIDE RANGE
10% remain mild or relatively only gradually progressive
In the ddx of PD what alternative diagnoses the ff symptoms suggest?
- Early falls and vertical gaze impairment
- Dysautonomia with fainting, bladder or vocal cord dysfunction
- Early and rapidly evolving dementia or intermittent psychosis
- Apraxia
- PSP
- MSA
- LBD
- Corticobasal ganglionic degeneration
- Early falls and vertical gaze impairment
- Dysautonomia with fainting, bladder or vocal cord dysfunction
- Early and rapidly evolving dementia or intermittent psychosis
- Apraxia
What is the typical clinical phenotype of vascular dementia patients?
“Lower half parkinsonsim” whereby predominant symptoms are shuffling gait, stickiness on turning and falling with little or no response to levodopa
How does essential tremor differ from PD?
- Disappears at rest present on movement
2. Faster
Besides the substantia nigra what other areas of the brain lose their pigmented nuclei?
Locus ceruleus and dorsal motor nucleus of the vagus
What are lewy bodies?
Eosinophilic cytoplasmic inclusions containing ubiquitin and synuclein found in all cases of idiopathic parkinson disease.
ALPHA SYNUCLEIN IS THE MAIN COMPONENT OF LEWY BODIES
According to Braak and Braak, where does the earliest change in the brain occur in PD?
- Dorsal glossopharyngeal-vagal nuclei
2. Anterior olfactory nuclei
What neurotoxin produces pyridinium MPP that binds to melanin in dopaminergic cells in enough concentration to initiate destruction of these cells
What is the % of familial occurrence with Parkinson Disease?
MPTP
1 methyl 1,4 phenyl 1,2,3,6 tetrahydropyridine
15%
What genetic defect
- Accounts for 50% of early onset inherited PD and 20% of sporadic early onset ones, AR
- 2 main mutations A53T and A30P promote oligomerization of alpha synuclein, AD (early onset as well)
- In ashkenazi jews protein is also called dadarin– aka LRRK2 protein, AD (late onset), 5-8% of familial PD
- Mitochondrial gene with AR inheritance
- Late onset dystonia parkinsonism unknown mode of inheritanec
- Park 2, parkin
- Park 1, SCNA alpha synuclein
- Park 8, LRRK2, leucine rich repeat kinase 2
- PINK1/ Park 6
- Park14 PLA2G6
What phenomena underlies dyskinesias in the treatment of PD with levodopa?
Denervation hypersensitivity of striatal target neurons
What are the 3 side effects of levodopa?
Nausea
Hypotension
Confusion
What does entacapone do to levodopa?
How about carbidopa?
COMT inhibitor that extends plasma half life and duration of levodopa effect by preventing its breakdown
Prevent peripheral decarboxylation of L-dopa to dopaine permitting a greater proportion of L-dopa to reach nigral neurons
What group of PD meds can be given early in the disease where tremor is the only manifestation?
Anticholinergics: Trihexyphenidyl and Benztropine
T or F: Patients give levodopa early in the disease survived longer and with less disability than those who began the medication late in the course
T