Alzheimer’s disease Flashcards
Protective factors
smoking
hrt (oestrogen)
NSAIDs
higher level of pre-morbid education
Pathophysiology
micro + macroscopic
- Degeneration of cholinergic neurones in nucleus basalis of Meynert → def. in Ach
- Microscopic changes: neurofibrillary tangles (intracellular) + beta-amyloid plaque formation (extracellular)
- Macroscopic changes: cortical atrophy (commonly hippocampal), widened sulci, ventricle enlargement
Genetics
- Early onset Alzheimer’s: presenilin 1 (chromosome 14), presenilin (chromosome 2), amyloid precursor protein (chromosome 21 → TRISOMY 21 [Down’s] therefore more likely to get early onset dementia as more likely to have this gene as 3 chrom. 21s)
- Later onset Alzheimer’s: ApoE-4 (chromosome 19)
RFs
Advancing age FHx (1st degree) Genetics (above) Down’s syndrome low IQ + lower education attainment cerebrovascular disease vascular RFs (Past stroke/MI, smoking, HTN, DM, ^ cholesterol)
CFs
Summary: Early memory loss + focal cognitive defects → later manifestations = personality changes
early symptoms
Early Sx’s →
failing memory (esp. disorientation for time)
muddled efficiency w/ ADLs, spatial dysfunction
behaviour changes (irritable)
difficulty finding words
forgetting names of people/places
middle symptoms
Middle Sx’s → intellectual and personality deterioration apraxia confusion language problems (aphasia) difficulty w/ executive thinking
late symptoms
Late Sx’s → eating problems depression agitation personality changes dependent physical deterioration incontinence gait problems weight loss primitive reflexes
psychiatric and behavioural symptoms
Psychiatric Sx’s → delusions (esp. paranoid), auditory ± visual hallucinations (simple misidentification), depression (common)
Behavioural Sx’s → aggression, wandering, explosive temper, sexual disinhibition, incontinence, excessive eating, searching behaviour
features of early onset Alzheimer’s
<65y/o
rapid
aphasia
apraxia
define aphasia
person’s problem in ability to understand speech
define apraxia
inability to carry out previously learnt purposeful movements (including speech) despite normal coordination + strength
(cant give x’s cos can’t move their mouth)
What 5 things do pts have impairment with relating to cognitive and executive functions
- Executive → problem solving, abstract thinking, reasoning, deciding, judgement, planning, organising, processing
- Visuospacial abilities → getting lost, copying figures
- Language disturbances (decreased vocab, word finding difficulty, preservation [repetition], aphasia…)
- Apraxia → inability to carry out previously learnt purposeful movements (including speech) despite normal coordination + strength
- Agnosia (impaired recognition of sensory stimuli w/out sensory loss)
Ix
- Hx
- MSE: important to note clouding of consciousness (delirium)
- Cognitive testing: MMSE + AMT
- Physical examination: focal signs, reflexes, plantar responses, gait disturbance, PD signs
- Blood tests
a. FBC, , LFT, U/E, glucose, ESR, TSH/TFTs, calcium, magnesium, phosphate, syphilis tests, HIV screen, vit B12, folate, CRP, blood culture - LP → exclude CJD (Creutzfeldt-Jakob disease)
- EEG → CJD + frontotemporal dementia
- CXR (pneumonia, lung tumour [e.g. SCLC → hyponatraemia [confusion]])
- Urine dipstick (UTI)
- ECG → CVD
- Brain imaging → indicated if <60
a. CT (head)/MRI - Genetic tests: HD + familial dementia
- Referral to memory clinic
ALWAYS remember that calcium is separate from U+Es (therefore give both in answers)
ICD-10 criteria for disease (early onset and late onset)
- Criteria for dementia met
- No evidence for any other possible cause of dementia
- Early onset AD:
(1) + (2) + <65
o Rapid onset + progression
o Memory impairment + aphasia, agraphia (decreased ability to communicate through writing), alexia (decreased ability to read), acalculia (decreased ability to perform maths tasks) or apraxia - Late onset AD:
(1) + (2) + Age >65
One of:
• Slow, gradual onset and progression
• Predominance of memory impairment over intellectual impairment
