Understanding Neurodegenerative Diseases

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Questions and Answers

What is the primary characteristic of neurodegenerative diseases?

Gradual improvement of neuronal function with age

Progressive loss of neurons, typically affecting groups of neurons with functional relationships (correct)

Progressive loss of neurons in adjacent groups

Accumulation of protein aggregates in specific brain regions

What is the morphologic hallmark of neurodegenerative diseases?

Inflammation of neuronal tissue

Accumulation of protein aggregates (correct)

Demylination of neuronal axons

Fibrosis of neuronal tissue

What is the basis for protein aggregation in Huntington disease?

Environmental toxins

Directly related to an intrinsic feature of a mutated protein (correct)

Intrinsic feature of a peptide derived from a larger precursor protein

An unexplained alteration of a normal cellular protein

What is the most common cause of dementia in older adults?

Alzheimer disease Signup and view all the answers

At what age do patients with Alzheimer disease typically become symptomatic?

After 50 years of age Signup and view all the answers

What is the typical duration of progressive disability in Alzheimer disease?

5-10 years Signup and view all the answers

What is the primary mechanism by which alterations in tau phosphorylation contribute to cognitive impairment in Alzheimer disease?

Tau phosphorylation causes oxidative injury to neurons Signup and view all the answers

Which of the following microscopic findings in Alzheimer disease is characterized by focal, spherical collections of dilated, tortuous, neuritic processes?

Neuritic plaques Signup and view all the answers

What is the primary association of a large burden of plaques and tangles in Alzheimer disease?

Severe cognitive dysfunction Signup and view all the answers

Which of the following biochemical markers is correlated with the degree of dementia in Alzheimer disease?

Amyloid burden Signup and view all the answers

What is the characteristic staining pattern of neurofibrillary tangles in Alzheimer disease?

Basophilic by H&E staining Signup and view all the answers

Which of the following structures is involved early in the course of Alzheimer disease and is usually severely atrophied in the later stages?

All of the above Signup and view all the answers

What is the primary distinguishing feature of Frontotemporal Lobar Degenerations (FTLDS) from Alzheimer disease?

Alterations in personality, behavior, and language preceding memory loss Signup and view all the answers

Which of the following is a characteristic of the final stages of Alzheimer disease?

Incontinence and muteness Signup and view all the answers

What is the underlying morphology of Pick disease?

Tau-containing inclusions Signup and view all the answers

What is the frequency of Frontotemporal Lobar Degenerations (FTLDS) compared to Alzheimer disease in individuals under the age of 65?

Equally frequent Signup and view all the answers

Which of the following is NOT a characteristic of Frontotemporal Lobar Degenerations (FTLDS)?

Involvement of the parietal and occipital lobes Signup and view all the answers

What is the primary difference in microscopical morphology between Alzheimer disease and Frontotemporal Lobar Degenerations (FTLDS)?

Presence of tau-containing inclusions Signup and view all the answers

What is the characteristic of the inclusions found in Pick cells?

Weakly basophilic but stain strongly with silver methods Signup and view all the answers

Which of the following is a hallmark of Parkinson's disease?

Lewy bodies Signup and view all the answers

What is the characteristic of neuronal loss in Parkinson's disease?

It is typically accompanied by gliosis Signup and view all the answers

Which of the following is a characteristic of dementia with Lewy bodies?

Dementia develops at least one year prior to the onset of parkinsonism Signup and view all the answers

What is the characteristic of Lewy neurites?

They are dystrophic processes that contain aggregated α-synuclein Signup and view all the answers

What is the characteristic of the substantia nigra in Parkinson's disease?

It shows pallor macroscopically Signup and view all the answers

What is the characteristic movement disorder seen in Huntington disease?

Chorea Signup and view all the answers

Which brain regions are involved in Huntington disease, apart from the striatum?

Globus pallidus, substantia nigra, cerebral neocortex, entorhinal cortex, and hypothalamus Signup and view all the answers

What is the range of CAG repeats in the gene coding for huntingtin protein in Huntington disease?

36-86 Signup and view all the answers

What is the significance of the term 'autosomal dominant' in Huntington disease?

A single copy of the mutated gene is enough to cause the disease Signup and view all the answers

What is the characteristic pathology seen in the striatum in Huntington disease?

Neuronal loss and gliosis Signup and view all the answers

What is the clinical manifestation of Huntington disease apart from chorea?

Psychiatric and cognitive symptoms, and cachexia Signup and view all the answers

Study Notes

Neurodegenerative Diseases

Characterized by progressive neuronal loss involving specific neuronal circuits and brain regions
Associated with accumulation of abnormal protein aggregates, typically in the form of cellular inclusions
Clinical phenotype reflects the patterns of brain involvement more than the type of inclusions

Pick's Disease

Microscopically: swelling neurons (Pick cells) with cytoplasmic, round to oval, filamentous inclusions (Pick bodies)
Weakly basophilic but stain strongly with silver methods and contain 3R tau

Parkinson's Disease (PD)

A neurodegenerative disease marked by a prominent hypokinetic movement disorder
Caused by loss of dopaminergic neurons from the substantia nigra
Presumptive diagnosis based on the presence of the central triad of parkinsonism—tremor, rigidity, and bradykinesia—in the absence of a toxic or other known underlying etiology
Macroscopically: pallor of the substantia nigra
Microscopically: Lewy bodies and areas of neuronal loss with gliosis

Dementia with Lewy Bodies

Dementia developed at least one year prior to the onset of parkinsonism
Microscopically: cortical Lewy bodies similar to classical Lewy bodies but seen in the cortex

Huntington's Disease (HD)

An autosomal dominant disease characterized by progressive movement disorders and dementia
Caused by degeneration of striatal neurons
Mutation in gene coding for huntingtin protein on chromosome 4: 36–86 CAG repeats
Clinical manifestation: chorea, psychiatric and cognitive symptoms, and cachexia
Macroscopic: variable cerebral atrophy, depending on the stage of disease, with atrophy of striatum (caudate nucleus and putamen)
Microscopic: neuronal loss and gliosis in striatum, with globus pallidus, substantia nigra, cerebral neocortex, entorhinal cortex, and hypothalamus also involved

Alzheimer's Disease (AD)

The most common cause of dementia in older adults
Typically becomes symptomatic after 50 years of age, with incidence increasing with age
Causes alterations in tau phosphorylation, along with oxidative injury to neurons
Basis for cognitive impairment: presence of a large burden of plaques and tangles, with biochemical markers including loss of choline acetyltransferase and amyloid burden
Macroscopic: cortical atrophy most pronounced in the frontal, temporal, and parietal lobes, with secondary ventricular enlargement
Microscopic: neuritic (senile) plaques and neurofibrillary tangles, with progressive neuronal loss and reactive gliosis

Frontotemporal Lobar Degenerations (FTLDs)

One of the more common causes of early onset dementia, occurring at the same frequency as Alzheimer disease in those under the age of 65 years
Distinguished from AD by the fact that alterations in personality, behavior, and language (aphasias) precede memory loss
FTLD is associated with cellular inclusions of specific proteins
Macroscopically: atrophy of frontal and temporal lobes to variable extent and severity
Microscopically: neuronal loss, gliosis, and the presence of tau-containing neurofibrillary tangles
Pick disease: a subtype of FTLD-tau, characterized by severe circumscribed asymmetric “knife-edge” atrophy of frontal and temporal lobes with conspicuous sparing of the posterior two thirds of the superior temporal gyrus and only rare involvement of either the parietal or occipital lobe

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Description

Test your knowledge of neurodegenerative diseases, including their characteristics, classification, and common pathologic processes. This quiz covers the progressive loss of neurons, genetic and molecular studies, and more. Learn about the features shared across various neurodegenerative diseases.