S4: Dementia Flashcards
Define Dementia
Dementia is defined as a syndrome of global impairment and deterioration in cognition leading to a decline in functioning in clear consciousness (i.e. consciousness is not affected).
- Alzheimer’s is the most common type of dementia, multi-infarct (vascular) dementia is another type, Lewy-body dementia is another and frontotemporal dementia.
What is a syndrome?
A syndrome is a collection of signs and symptoms.
Describe clinical syndrome of dementia
- Neuropsychological symptoms -> amnesia, aphasia, apraxia, agnosia (4As), we can measure these by using screening tools such as the MMSE (mini mental state examination), Addenbrooke’s Cognitive Examination or the MOCA (Montreal Cognitive Assessment).
- Neuropsychiatric symptoms -> Referred to as BPSD, behavioural and psychiatric disorders in dementia, examples include depression, paranoia, hallucinations, anxiety, aggression, wandering, personality change. These symptoms appear as the dementia progresses.
- However in order to be diagnosed as dementia, these symptoms must impact on daily living!
What are the two categories that activities of daily living fall into?
- Instrumental (looking after finances, going shopping, cooking, driving).
- Basic (dressing, washing, going to toilet).
How does dementia affect the types of activities differently?
Instrumental activities tend to be affected earlier on in dementia, then as it progresses the basic activities start to get affected.
Describe the ICD-10 diagnosis of dementia
G1i) A decline in memory (both verbal and non verbal). Most evident in the learning of new information.
G1ii) Decline in other cognitive abilities. ‘planning and organizing and in general processing of information.
- Decline objectively verified by informant and quantified cognitive assessments.
- Can be quantified as mild, moderate or severe.
G2) Awareness of environment is preserved (i.e. not delirium).
G3) Decline in emotional control or a change in social behaviour (lability, irritability, motivation, apathy).
G4) Symptoms present for > 6 months.
What are the 4 main dementia types?
- Alzheimer’s disease (50-60% of dementia).
- Vascular dementia (15-20% of dementias).
- Dementia with Lewy bodies (10-15%).
- Frontotemporal (4-6%, however tends to affect younger people below 65, in this age group makes up 20%).
Describe the epidemiology of dementia
The overall prevalence of dementia in those aged over 65+ is 7-10%, the prevalence actually doubles every 5yrs from 60-90. E.g. 60-65 (1%), 65-70 (2%), 70-75 (3-5%) etc. The incidence of dementia in those over 75+ is 45 per 1000.
Diagnosis pathway of dementia
- GP.
- Referral to memory clinic.
- Diagnosis: history, cognitive testing (e.g. Addenbrooks –> different domains of memory tested), collateral history (as early on patient usually realises they have memory problems while later on they may not realise) , any reversible causes (e.g. Tests for folate, thyroid function).
- Outcome of assessment:
- No problem or problem.
- Mild cognitive impairment is where memory is worse than expected for age (abnormal ageing) but no significant impact on daily life. This makes the patient more likely to develop dementia but it is not treated.
- Dementia –> scan is not always needed for diagnosis.
- Imaging (clarifying diagnosis e.g. CT scan for dementia, Alzheimer’s).
Describe clinical presentation of Alzheimer’s (AD)
HISTORY:
- Usually some awareness of failing memory e.g. forgetting what you ate for breakfast.
- Concentration and general knowledge ok.
FAMILY:
- 2-3 decline, repetitive.
- Preserved language and practical skills, some problems managing accounts.
PHYSICAL:
- Nil of note.
ACE-III (Addenbrooke’s cognitive examination):
- Some impairment on attention.
- Impaired memory (normal registration but very poor delayed recall).
- Mild impairment on naming.
- Language and visuospatial reasonably intact.
MRI/CT head:
- Hippocampal atrophy mainly seen on scans.
7 A’s of Alzheimer’s (symptoms)
- Anosognosia: This is a late sign and means that you no longer realise that there is something wrong. You might not understand why you have a memory problem or that you have a memory problem at all.
- Aphasia is the loss of ability to use language. This includes the ability to speak, understand, read and write.
- Altered perception which is when you misinterpret the information your senses are giving you. For some people, this is a bigger problem in the later afternoon or early evening when light changes.
- Apathy is not having drive or initiative. The part of brain that helps you start to do something either to carry out an activity or to communicate is damaged.
- Agnosia means recognising things through senses is damaged e.g. sight, sound, taste, touch and smell.
- Apraxia means you have lost the ability to tell your body how to carry out purposeful movement.
- Amnesia means loss of memory. This is important because everything we do depends on our ability to remember. At the beginning short term memory will be lost and eventually long term memory will go as well.
List non cognitive features of AD
They are psychiatric disturbances such as:
- Depression and anxiety.
- Psychosis (can be persecutory delusions e.g. thinks people stealing from them or partition delusions i.e. objects/people coming through walls) and hallucinations.
- Aggression, wandering (walking aimlessly around), shouting-out.
- Personality change.
- Apathy (lack of interest), or the opposite, disinhibition (lack of restraint).
List risk factors for AD
- Being female (could be that women live longer).
- Increasing age.
- Vascular risk factors (e.g. having diabetes, hypertension or atrial fibrillation).
- A family history of AD.
- Apo E4 allele status.
- Having hypothyroidism RR2.3.
- Head trauma RR1.8.
- Being less educated (people who are more educated have more IQ/cognitive reserve so AD symptoms come on much slower). More education –> more neuronal connections –> bigger IQ reserve. So dementia is shrinking brain at same rate but dementia doesn’t look as advanced as in uneducated person.
- So a person who has any of these things is at increased risk of AD.
Natural history/timeline of AD
- Symptoms of AD are generally present for 1-3 years prior to referral to secondary care.
- The total illness duration is 10-12 years.
- There is a decrease of about 3 points per year on the MMSE test from moderate to severe AD.
Pathophysiology of Alzheimer’s
- AD is caused by a number of changes in the brain, we see death of neurones particularly cholinergic neurones.
- Also seen and to blame is the presence of amyloid plaques these are aggregates of misfolded beta amyloid protein, they are derived from improper cleavage of amyloid precursor protein (APP). The amyloid plaques are toxic to nerve cells.
- We also see neurofibrillary tangles, these are hyperphosphorylated tau protein that disrupt neurones cytoskeleton leading to neuronal dysfunction and death.
- Both amyloid plaques and the tangles are needed to lead to neuronal damage.
- ApO E.
- Also we see vascular pathology that leads to inflammation.
Drug management of AD
EARLY DEMENTIA:
- Cholinesterase Inhibitors (increase Ach in brain) AND important to monitor pulse on this.
E.g. Donepezil is OD tablet. It is the most commonly used in AD treatment and well tolerated by patients.
E.g. Rivastigmine in patch or BD tablets. If you have GI effects from donepezil this is given or if you struggle taking tablets.
E.g. Galantamine.
LATER DEMENTIA:
- NMDA receptor antagonist. E.g. Memantine to calm down hyperalertness.
Describe vascular dementia
- Post Stroke.
- Often mixed with AD: mixed Alzheimer’s and vascular dementia.
- Extensive small vessel cerebrovascular disease.
Vascular dementia is caused by reduced blood supply to the brain due to diseased blood vessels. This leads to neuronal cell death causing symptoms of dementia. - Stepwise decline :
Patchy decline e.g. good normal memory but lose their language.
Types of vascular dementia
- Large vessel disease caused by:
- Strategic single infarct e.g. in thalamus.
- Multiple cortical grey matter infarcts (MID).
- 20-30% post-stroke develop dementia (not immediately after the stroke). - Small vessel disease is most common type caused by:
- Multiple lacunar infarcts (white matter) due to occlusion of single deep perforating artery.
Clinical presentation of vascular dementia
- A 1-2yr history of a deterioration in memory, apathy and limited insight, also a stepwise deterioration (being fine for a while, then declining, then remaining stable then declining).
- Family would report that individual has fluctuating cognition and is more confused at night with some emotional lability (pseudobulbar signs, uncontrolled laughing or crying or other emotional displays).
- A PMH of hypertension, high cholesterol, previous MI and recent TIA.
- ACE III (addenbrookes) would find an episodic memory deficit less severe than in AD, also executive defects.
- MRI would find diffuse white matter pathology as a consequence of occlusion of deep blood vessels.
Difference Parkinson’s Disease Dementia/ Dementia with Lewy Bodies
PDD and DLB are similar and essentially two conditions on a spectrum:
- PDD is diagnosed if the Parkinsonian symptoms have existed for at least 12 months prior to the dementia.
- DLB is diagnosed if both motor and cognitive symptoms develop within 12 months, or cognitive symptoms prior to motor.
Describe Dementia with Lewy Bodies (DLB)
- Someone with Lewy body dementia has neuronal inclusions (protein aggregates) and abnormally phosphorylated neurofilaments, also ubiquination of α synuclein.
- These are found in the paralimbic, neocortical areas and brainstem and this is responsible for the cognitive symptoms, there is a marked decline in Ach.
- We also see Lewy neurites (small cytoplasmic projections of neurones that are degenerated) and some amyloid plaques.
Clinical features of DLB
The clinical features of DLB are quite distinct and different from AD, we see:
- Dementia (generally relating to attention and visuospatial).
- Fluctuating cognitive performance and level of consciousness (the most characteristic feature e.g. in middle of convo start staring into space).
- Visual hallucinations (very common, 60% of DLB, seeing people in house (not little hallucinations)).
- Parkinsonism (70% of DLB).
- Falls.
- Very sensitive to antipsychotics (psychosis caused by high DA, giving antipsychotics decreases DA and this worsens.
- Parkinsonian symptoms. We should avoid giving antipsychotics.
- REM sleep disorder (they have vivid dreams generally nightmares, may be acted out).
Describe Parkinson’s Disease Dementia:
PDD is dementia that is a direct pathophysiological consequence of Parkinson’s disease, as mentioned earlier it is where someone has Parkinson’s for at least 12 months and then starts to develop dementia.
Clinical features of Parkinson’s Disease Dementia
Parkinson’s disease is characterised by motor symptoms, however there is increasing understanding of non-motor symptoms of Parkinson’s including:
- Dementia.
- Depression.
- Psychosis.
- REM sleep disorder.
In terms of epidemiology, 60-75% of PD patients will eventually develop dementia.