Alzheimer’s Disease
Definition:
Primary neurodegenerative disease that causes progressive cognitive deterioration, episodic memory loss, and language and planning defect, with no sensory or motor defect.
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Characterized byβ-amyloid deposits and neurofibrillary tangles in the cerebral cortex and subcortical gray matter.
Epidemiology:
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Most common type of dementia accounting for 66% of all dementia cases.
Risk Factors:

Study guide:
Pathophysiology:
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A β amyloid is derived from APP (amyloid precursor), which is coded on chromosome 21, through alpha and beta cleavage.
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Amyloid may also deposit around the vessels (amyloid angiopathy), which increase the risk of hemorrhage.
Neuritic plaques:
A beta Amyloid + entangled neuritic processes
Neurofibrillary tangles (intracellular):
hyperphosphorylated tau protein
Loss of cholinergic neurons in the neucleus basalis of Meynert in the basal forebrain

Clinical Presentation:
Type
Examples
Early+stages
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Memory impairment
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Language impairment
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Agnosia: failure to recognize objects
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Apraxia: inability to learn new skills
Intermediate+ stages
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Memory impairment
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Behavioral changes: hostility, aimless actions, and inappropriate judgment
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Personality changes: irritability, anxiety, and depression
Late+stages
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Daily activities are markedly impaired
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Loss of episodic and distant memories
Advanced+stages
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Inability to swallow
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Debilitation
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Increased risk of malnutrition, infections, and aspiration (common cause of death)
Diagnosis:
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DX is mainly through clinical history and evidence of significant memory impairment.
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Others:
CT Scan:
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Non-specific
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Diffuse atrophy of the brain especially in the temporal lobe
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Compensatory enlargement of the ventricles
MRI:
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Atrophy of the temporal lobes and hippocampi.
Other Tests:
to exclude other types of dementia
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Please refer to the dementia summary file
Management:
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Cholinesterase inhibitors: (donepezil, rivastigmine and galantamine):
-> 1st line therapy for AD
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NMDA receptor antagonist: (memntine).
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Dietary supplements (ginko, lecithin).
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Vitamen E in some studies shown to slow the disease progression.
Prognosis:
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If AD left untreated, the patient will be bedridden and mute in just 5-10 years.
References:
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Agabegi, Steven S, Elizabeth D Agabegi, and Adam C Ring. Step-Up To Medicine. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins, 2013. Print.
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Kumar, Parveen J, and Michael L Clark. Kumar & Clark's Clinical Medicine. Print.
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Hauser, Stephen, and Scott Josephson. Harrison's Neurology In Clinical Medicine. 3rd ed. McGraw Hill. Print.
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Yogarajah, Mahinda. Neurology. Edinburgh: Mosby/Elsevier, 2014. Print.
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Latest Facts & Figures Report | Alzheimer's Association,. 'Latest Alzheimer's Facts And Figures'. N.p., 2013. Web. 23 Sept. 2015.
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Sattar, Husain A. Fundamentals Of Pathology. Chicago: Pathoma.com, 2011. Print.
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Le, Tao, Vikas Bhushan, and Herman Singh Bagga. First Aid For The USMLE Step 2 CK. New York: McGraw-Hill Medical, 2010. Print.
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Alzheimer's Disease,. 'Creutzfeldt-Jakob Disease'. N.p., 2013. Web. 24 Sept. 2015. (Figure 1).
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Frontalcortex.com,. 'Alzheimer's Disease, Hippocampus, H&E 200X'. N.p., 2015. Web. 24 Sept. 2015. (Figure 2).
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MD, Edward. 'Cell Injury'. Library.med.utah.edu. N.p., 2015. Web. 24 Sept. 2015. (Figure 3).
First author: Roaa Amer
Second authors : Abdullah AlAsaad
Lama AlLuhaidan
Reviewers: Abdulrahman Al Nasser
Bayan AlZomaili
Format Editor : Adel Yasky
Audio recording:
- Read by: Nada Alhassan
- Directed by: Rana Alzahrani
- Audio production: Bayan Alzomaili