Alzheimer's Flashcards
definition of dementia
progressive clinical syndrome where the deterioration of mental function is significant enough to interfere with activities of daily living
criteria for the diagnosis of dementia to be make ;
patient must have;
- impairment in atleast two cognitive domains such as ; memory, thinking, language, orientation + judgement
- leading to significant functional decline enough to effect activities of daily living
- cannot be explained by
another disorder or adverse effects of medication
Pathophysiology of Alzheimer’s disease
- most common cause of dementia
- Development of plaques
- amyloid precursor proteins are proteins which help neurons grow and repair
- beta amyloid plaques are fragments of amyloid precursor proteins
- beta amyloid plaques can break off and form clumps of protein plaques which can interrupt signals between neurons - reduction in acetylecholine production -> memory loss
- Amyloid deposits in blood vessels walls - accumulate and weaken the vessels increasing risks of hemorrhaging
- Trigger neurofibrillary tangles - accumulate within the nrurons and this prevents effective signally which can lead to apoptosis
clinical features of Alzheimer’s
- generalised atrophy of the brain
- Gyrie become narrower
- Sulci get wider
- Ventricles get larger
Risk factors
Down’s
Early onset Alzheimer’s ( < 65 )
Has a very strong genetic link
- Amyloid precursor protein on chromosome 21
- adults with down’s syndrome (trisomy 21) likely to develop Alzheimer’s due to triplication of chromsome 21
- as there is over expression of gene for amyloid precursor protein - Presenilin 1 and 2 (PSEN 1 or PSEN 2)
- PSEN 1 on chromosome 14 and PSEN 2 on chromosome 1 - These genes virtually guarantee that the indivisual will develop Alzheimer’s disease
Environmental factors contributing to Alzheimer’s disease
- Aluminium in Alzheimer’s disease in dialysis patients
- low social class + nutrition
- HRT - a protective factor
Macroscopic changes seen in Alzheimer’s
widespread cerebral atrophy, particularly involving the cortex and hippocampus
non pharmacological management of Alzheimer’s
NICE recommend;
1. offering ‘a range of activities to promote wellbeing that are tailored to the person’s preference’
- offering group cognitive stimulation therapy for patients with mild and moderate dementia
- other options to consider include group reminiscence therapy and cognitive rehabilitation
First line pharmacological management of Alzheimer’s
Three acetylcholinesterase inhibitors; - donepezil - galantamine - rivastigmine as options for managing mild to moderate Alzheimer's disease
Second line pharmacological management of Alzheimer’s
memantine (an NMDA receptor antagonist) is in simple terms the ‘second-line’ treatment for Alzheimer’s,
NICE recommend it is used in the following situation reserved for patients with
→ moderate Alzheimer’s who are intolerant of, or have a contraindication to, acetylcholinesterase inhibitors
→ as an add-on drug to acetylcholinesterase inhibitors for patients with moderate or severe Alzheimer’s
→ monotherapy in severe Alzheimer’s
Managing non cognitive symptoms of Alzheimer’s
- NICE does not recommend antidepressants for mild to moderate depression in patients with dementia
- antipsychotics should only be used for patients at risk of harming themselves or others, or when the agitation, hallucinations or delusions are causing them severe distress
What are neurofibrillary tangles?
- Neurofibrillary tangles
paired helical filaments are partly made from a protein called tau
in AD are tau proteins are excessively phosphorylate
Microscopic changes seen;
- cortical plaques due to
- deposition of type A-Beta-amyloid protein
- intraneuronal neurofibrillary tangles caused by abnormal aggregation of the tau protein
What is there a deficiency of?
deficit of acetylcholine from damage to an ascending forebrain projection