Neurodegenerative diseases

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Neurodegenerative diseases is a big part of neuropathology.

Overview

  • Neurodegenerative disease = essentially progressive and selective neuron loss.
  • Clinically, they are not unique, e.g. dementia can be caused by several diseases (with different molecular etiologies).
    • Each syndrome (e.g. dementia, parkinsonism, ataxia) has a most common etiology and a DDx.
  • They are defined by molecular pathology.[1]
    • The diseases are due to the accumulation of abnormal protein.
      • The amino acid sequence of the protein may be completely normal. The problem may just be folding/protein conformation.

Molecular schema of neurodegenerative disorders:[1]

 
 
 
 
 
 
Neurodegenerative
disorders
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Amyloidoses
 
Tauopathies
 
α-synucleinopathies
 
TDP-43
 

Common diseases

Amyloidoses:

  • Alzheimer disease (Abeta).
  • Creutzfeldt-Jakob disease (PrP).

Taupathies:

  • Progressive supranuclear palsy.
  • Pick's disease.

Synucleinopathies:[2]

  • Parkinson disease.
  • Dementia with Lewy bodies.
  • Multiple system atrophy.

TDP-43 proteinopathies:

  • Amyotrophic alteral sclerosis.
  • Frontotemporal lobar degeneration with ubiquitinated inclusions.

Table

Disease/pathology/clinical correlation based on Dickson:[1]

Disease Mutated protein Distribution Clinical Histology Image
Alzheimer disease Abeta (mutated APP) corticolimbic, usu.
spares occipital 		dementia plaques, neurofibrillary tangles ??? Image?
Creutzfeldt-Jakob disease PrPres (mutated PrP) cortical & basal ganglia dementia (rapid progression),
movement disorder 		cytoplasmic vacuolization Image?
Progressive supranuclear palsy tau 4R basal ganglia, brainstem parkinsonism globose neurofibrillary tangles
in neurons, coiled bodies
in oligodendrocytes 		Image?
Pick disease tau 3R corticolimbic dementia + focal
cortical syndrome 		Pick body ??? Image?
Parkinson disease alpha-synuclein brainstem parkinsonism Lewy bodies Image?
Dementia with
Lewy bodies 		alpha-synuclein corticolimbic, brainstem dementia + parkinsonism Lewy bodies Image?
Multiple system atrophy alpha-synuclein basal ganglia, brainstem, cerebellum parkinsonism, ataxia cytoplasmic inclusion in oligodendrocytes[3] Image
Amyotrophic lateral
sclerosis (ALS) 		TDP-43 motor neurons spasticity, weakness histology? Image
Frontotemporal lobar
degeneration with
ubiquitinated inclusions 		TDP-43 cortex, basal ganglia dementia, focal cortical syndromes histology? Image?

IHC

Alpha-synuclein

Look for:

  • Lewy bodies (seen in Parkinson's d., Dementia with Lewy bodies) = round cytoplasmic eosinophilic body +/- pale halo.

Tau

  • AT-8 = stains phosphorylated tau.[4]

TDP-43

  • May accumulate due to a progranulin mutation.

Microscopic

Ubiquitin

  • Marks proteins for recycling.

Microscopic

  • p62; poli-ubiquitin-binding protein p62.[4]

Look for:

  • Lewy bodies. (???)

Clinical perspective (becoming obsolete)

General (mostly useless) DDx

  • Alzheimer's dementia - most common.
  • Vascular.
    • Multi-infarct dementia.
  • Parkinson's associated dementia.
  • Lewy body dementia.
  • Alcohol-related dementia.
  • Fronto-temporal dementia (Pick disease).
  • Multisystem atrophy.

Mnemonic

Mnemonic VITAMIN D VEST:[7]

  • Vitamin deficiency (B12, folate, thiamine).
  • Infection (HIV).
  • Trauma.
  • Anoxia.
  • Metabolic (Diabetes).
  • Intracranial tumour.
  • Normal pressure hydrocephalus.
  • Degenerative (Alzheimer's, Huntington's, CJD).
  • Vascular.
  • Endocrine.
  • Space occupying lesion (chronic subdural hematoma).
  • Toxins (alcohol).

Functional anatomy of dementia

  • Hippocampus (essential for forming new memories).
  • Frontal lobe (essential for retrieval of memories).

Alzheimer disease

General

  • Onset: episodic memory loss.

Gross

Features:

  • Temporal atrophy, esp. hippocampus.
  • Dilation of:
    • Lateral ventricles.
    • Third ventricle.

Gross/microscopic - disease spread by NF tangles (staging):[8]

  • Alzheimer "spreads" in a reproducible pattern:
    • Stage I-II: entorhinal cortex.
    • Stage III-IV: inferior aspect of brain.
    • Stage V-VI: limbic system.

Microscopic

Features:

  1. Neurofibrillary tangles.
  2. Senile plaques.
    • Consists of two components:
      1. Centre - radiates.
        • Consists of Abeta amyloid
      2. Neurites - swollen axons.
    • Considered to be more specific for Alzheimer's than NF tangles.
    • There is a staging system for plaques I (mild), II (moderate), III (severe).

Notes:

  • Abeta amyloid:
    • Derived from amyloid precursor protein (APP).
      • APP:
        • Rapid axonal transport - useful as a marker of axonal injury.
        • Function currently not known.
  • Tau:
    • Important in microtubule assembly.

Lewy body diseases

DDx:

  • Parkinson's disease.
  • Dementia with Lewy bodies.

Etiology:

  • Alpha-synuclein.

Clinical features of Dementia with Lewy bodies:

  • Parkinsonian features.
  • Hallucinations (visual).
  • Progressive cognitive decline with fluctuations.

Multiple system atrophy

General

Clinical findings variable:

  • Parkinsonism (stiatonigral degeneration).
  • Ataxia (olivo-panto-cerebellar degeneration).

Microscopic

Features:

  • Alpha-synuclein-rich glial cytoplasmic inclusions (finding at autopsy).[11]
    • Inclusions in oligodendrocytes.[12]

Progressive supranuclear palsy

General

  • AKA Steele-Richardson-Olszewski syndrome.
  • Diagnosis: clinical.[13]

Microscopic

Features:[1][13][14]

  • Globose neurofibrillary tangles in neurons.
  • Coiled bodies in oligodendrocytes.

Huntington disease

General

  • Autosomal dominant inheritance.
  • Mutation: unstable CAG repeat.[15]

Gross

  • Missing caudate.[16]

Image: Huntington's disease (ouhsc.edu).

Binswanger's disease

General

  • Multi-infarct dementia affecting subcortical white matter.
  • Waste-basket diagnosis; diagnosed if CADASIL and amyloidosis have been excluded.
  • Diagnosis has been controversial -- most with this entity (in the past) were diagnosed with Alzheimer's disease.

Microscopic

Features:

  • Subcortical lesions that replace the myelin consisting of macrophages.

Prion diseases

Etiology:[17]

  • Misfolded cell-surface protein called PrP(C).

Includes:[17]

  • Creutzfeldt-Jakob disease (CJD).
  • Sporadic fatal insomnia (sFI).

Creutzfeldt-Jakob disease

General

  • Commonly abbreviated as CJD.
  • Rare.
  • Incurable disease.
  • Usually diagnosed clinically.
    • Characteristic findings:
      • Very rapid decline (3-4 months).
      • Characteristic (cortex findings on) neuroradiology.

Variant Creutzfeldt-Jakob disease (vCJD)

  • Associated with bovine spongiform encephalopathy.
  • Should sample: spleen, lymph nodes, tonsils.[18]

Microscopic

Features:

  • Spongy appearance (cytoplasmic vacuolization[19]).

Images:

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 Dickson DW (2009). "Neuropathology of non-Alzheimer degenerative disorders". Int J Clin Exp Pathol 3 (1): 1–23. PMC 2776269. PMID 19918325. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2776269/?tool=pubmed.
  2. ↑ Uversky, VN. (Oct 2008). "Alpha-synuclein misfolding and neurodegenerative diseases.". Curr Protein Pept Sci 9 (5): 507-40. PMID 18855701.
  3. ↑ MUN. 15 November 2010.
  4. ↑ 4.0 4.1 Seelaar H, Klijnsma KY, de Koning I, et al. (May 2010). "Frequency of ubiquitin and FUS-positive, TDP-43-negative frontotemporal lobar degeneration". J. Neurol. 257 (5): 747–53. doi:10.1007/s00415-009-5404-z. PMC 2864899. PMID 19946779. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2864899/.
  5. ↑ Geser F, Brandmeir NJ, Kwong LK, et al. (May 2008). "Evidence of multisystem disorder in whole-brain map of pathological TDP-43 in amyotrophic lateral sclerosis". Arch. Neurol. 65 (5): 636–41. doi:10.1001/archneur.65.5.636. PMID 18474740.
  6. ↑ URL: http://dictionary.reference.com/browse/skein. Accessed on: 20 November 2010.
  7. ↑ TN06 PS19
  8. ↑ Braak H, Braak E, Bohl J (1993). "Staging of Alzheimer-related cortical destruction". Eur. Neurol. 33 (6): 403–8. PMID 8307060.
  9. ↑ URL: http://www.pakmed.net/academic/age/alz/alz030.htm. Accessed on: 12 November 2010.
  10. ↑ URL: http://faculty.washington.edu/alexbert/MEDEX/Fall/NeuroPath_Obj.htm. Accessed on: 13 November 2010.
  11. ↑ Wenning, GK.; Stefanova, N.; Jellinger, KA.; Poewe, W.; Schlossmacher, MG. (Sep 2008). "Multiple system atrophy: a primary oligodendrogliopathy.". Ann Neurol 64 (3): 239-46. doi:10.1002/ana.21465. PMID 18825660.
  12. ↑ MUN. 16 November 2010.
  13. ↑ 13.0 13.1 URL: http://emedicine.medscape.com/article/1151430-overview. Accessed on: 11 November 2010.
  14. ↑ Williams DR, Lees AJ (March 2009). "Progressive supranuclear palsy: clinicopathological concepts and diagnostic challenges". Lancet Neurol 8 (3): 270–9. doi:10.1016/S1474-4422(09)70042-0. PMID 19233037.
  15. ↑ Kumar P, Kalonia H, Kumar A (2010). "Huntington's disease: pathogenesis to animal models". Pharmacol Rep 62 (1): 1–14. PMID 20360611.
  16. ↑ URL: http://moon.ouhsc.edu/kfung/jty1/NeuroTest/Q07-Ans.htm. Accessed on: 29 October 2010.
  17. ↑ 17.0 17.1 Watts JC, Balachandran A, Westaway D (March 2006). "The expanding universe of prion diseases". PLoS Pathog. 2 (3): e26. doi:10.1371/journal.ppat.0020026. PMC 1434791. PMID 16609731. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1434791/.
  18. ↑ Burton, Julian L.; Rutty, Guy N. (2010). The Hospital Autopsy A Manual of Fundamental Autopsy Practice (3rd ed.). Oxford University Press. pp. 83. ISBN 978-0340965146.
  19. ↑ URL: http://moon.ouhsc.edu/kfung/jty1/opaq/PathQuiz/N0I002-PQ01-M.htm. Accessed on: 19 October 2010.
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