Dementia Flashcards
6CIT: 6 questions to asses brain function
What year is it? What month is it? Give an address with 5 parts (John, Smith, 42, High, St, Bedford) Count 20-1 Say months of year in reverse Repeat address
Diagnostic tests of Alzheimer’s disease
Structure (MRI or CT)
Pathology - non-invasive (amyloid and tau imaging)
Function-brain networks
Define dementia
A syndrome caused by a number of brain disorders (e.g. Alzheimer’s) which cause memory loss, difficulties with thinking, problem-solving or language as well as difficulties with activities of daily living
Revision question:
How would you make a clinical diagnosis of epilepsy
From history, there needs to be at least 2 unprovoked seizures occurring > 24hrs apart to DIAGNOSE EPILEPSY
Types of dementia
Alzheimers (50%)
Vascular (25%)
Lewy-body (17%)
Fronto-temporal
What is the most common cause of dementia
Alzheimers disease
Pathophysiology of Alzheimers disease
Accumulation of beta-amyloid peptide, a degradation product of amyloid precursor protein, results in progressive neuronal damage, neurofibrillary tangles, increases in the number of amyloid plaques and the loss of ACh.
Degenration of the cerebral cortex (with cortical atrophy)
Risk factors of Alzheimers
Down's syndrome due to increased APP gene load Familial gene associations Hypothyroidism Previous head trauma Family history of Alzheimer's disease
Examples of familial gene associations for Alzheimer’s disease
Amyloid precusor protein (APP) - chromosome 21
Presenilin-1 (chromosome 14)
Presenilin-2 (chromosome 1)
Apolipoprotein E4 (ApoE4) alleles - chromosome 19
Signs and symptoms of Alzheimers disease
Amnesia Disorientation Changes in personality Decreasing self care Apraxia Agnosia Aphasia Lexical anomia Paranoid delusions Depression Wandering Aggression Sexual disinhibition
Investigations of Alzheimers disease
Mini Mental State Examination
Addenbrooke’s Cognitive Examination (ACE-III)
Bloods - FBC, U&Es, LFTs, TFTs, CRP, ESR, glucose, magnesium, phosphate, VDRL, HIV, serology, vitamin B12 and folate levels, blood culture
ECG, lumbar puncture, CXR, CT scan, MRI scan, SPECT
Histology
3 main findings on histology of Alzheimers
BAT
Beta amyloid plaques
decreased Acetylcholine
neurofibrillary Tangles
Complications of Alzheimers
Amnesia Increased risk of infection Dysphagia Urinary incontinence Increased risk of falls
Treatment of Alzheimers
Memantine
Donepezil
Rivastigmine
How does Memantine work?
inhibits glutamate by blocking N-methyl-D-asparate (NMDA) receptors
How does Donepezil work?
Acetylcholinesterase inhibitor
How does Rivastigmine work?
Acetylcholinesterase inhibitor
What is second most common cause of dementia
Vascular dementia
Aetiology of Vascular dementia
Caused by infarcts of small and medium sized vessels in the brain
Brain damage due to cerebrovascular disease (major stroke, multiple unrecognised strokes or chronic changes in smaller vessels)
Genetic association with cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) on chromosome 19
Vascular dementia - follows a deteriorating stepwise progression. What are the 3 types
Vascular dementia following stroke
Multi-infarct dementia following multiple strokes
Binswanger disease following microvascular infarcts
Signs and symptoms of vascular dementia
Follows a deteriorating stepwise progression Amnesia Disorientation Changes in personality Decreasing self care Depression Signs of UMN lesions e.g. brisk reflexes Seizures
Investigations of vascular dementia
Mental state examination ACE-III
Bloods - FBC, U&Es, LFTs, TFTs, CRP, ESR, glucose, calcium, magnesium, phosphate, VDRL, HIV serology, vitamin B12 and folate levels, cholesterol levels, vasculitis screen, syphilis serology, ECG, lumbar puncture, CXR, CT scan, MRI scan, SPECT
Treatment of vascular dementia
Dietary advice
Smoking cessation
Treat DM and hypertension
Aspirin
Complications of vascular dementia
Significant co-morbidity e.g. cardiovascular disease and renal disease
What is the third most common cause of dementia
Lewy-body dementia
Which dementia is associated with Parkinsons
Lewy-body dementia
Causes of Lewy-body dementia
Associated with Parkinson’s disease
Avoid antipsychotic drugs in these patients
Signs and symptoms of Lewy-body dementia
Triad of:
- Parkinsonism - bradykinesia, gait disorder
- Hallucinations - predominantly visual hallucinations, usually of animals and people
- Disease process follows a fluctuating course
Investigations of Lewy-body dementia
Mental state examination ACE-III
CT scan, MRI scan, SPECT scan
Histology
What is found on histology of Lewy-body dementia
ApoE genotype Lewy bodies
Ubiquitin proteins
Alpha-synuclein
Treatment of Lewy-body dementia
AVOID ANTIPSYCHOTICS - causes hypersensitivity to neuroleptics
Levodopa - may be used to treat Parkinson’s symptoms but these may worsen psychotic symptoms
Complications of Lewy-body dementia
Neuroleptic hypersensitivity Autonomic dysfunction Fluctuating blood pressure Arrhythmias Urinary incontinence Dysphagia Increased risk of falls
What is Fronto-temporal dementia
Specific degeneration/atrophy of the frontal and temporal lobes of the brain
Mixed dementia
Parkinsons dementia*
Causes of fronto-temporal dementia
Genetic association with chromosome
17q21-22 and tau 3 gene mutations
Signs and symptoms of fronto-temporal dementia
Amnesia Disorientation Changes in personality Decreasing self care Mutism Echolalia Overeating Parkinsonism Disinhibition
Investigations of fronto-temporal dementia
Mini Mental state examination
ACE-III
CT scan, MRI scan, SPECT scan
Histology (depends on subtype)
Subtypes of fronto-temporal dementia
Microvascular type - microvacuolation
Motor neurone disease type - histological changes like MND
Pick type - widespread gliosis, no microvacuolation
Treatment of fronto-temporal dementia
Currently none
Only supportive treatment avaliable
Complications of fronto-temporal dementia
Increased risk of falls
Increased risk of infection
Other less common types of dementia
Huntingtons dementia Creutzfeldt-Jakob disease (CJD) HIV Vit B12 deficiency Syphilis Wilsons disease Dementia pugilistica (seen in boxers)
What is Wilsons disease
Autosomal recessive condition where copper accumulates within the tissue
Cause of Huntingtons dementia
Complication of Huntington’s disease (an autosomal dominant condition where theres a defective gene on chromosome 4)
Causes uncontrollable choreiform movements and dementia
Signs and symptoms of Huntingtons dementia
Uncontrollable choreiform movements Depression Irritability Anxiety Psychosis Obsessive compulsive behaviour
Investigations of Huntingtons dementia
Genetic testing (diagnostic)
Treatment of Huntingtons dementia
No cure
Treat symptoms:
Chorea - an atypical antipsychotic agent
Obsessive compulsive thoughts and irritability - selective serotonin reuptake inhibitors (SSRIs)
Complications of Huntingtons dementia
Dysphagia
Increased risk of falls and/or infection
What is Creutzfeldt-Jakob disease (CJD)
Caused by prions
Progressive and without cure
(Also variant Creutzfeldt-Jakob disease (vCJD) which has earlier death)
Signs and symptoms of Creutzfeldt-Jakob disease (CJD)
Rapidly progressive dementia (4-5 months) Amnesia Disorientation Changes in presonality Depression Psychosis Ataxia Seizures
Investigations of Creutzfeldt-Jakob disease (CJD)
EEG - triphasic spikes seen
Lumbar puncture (LP) - for 14-3-3 protein
CT scan
MRI scan
Treatment of Creutzfeldt-Jakob disease (CJD)
No cure
Complications of Creutzfeldt-Jakob disease (CJD)
Increased risk of infection
Coma
HF
Respiratory failure
Prevention of dementia
Healthy behaviours
Smoking cessation, good diet, physical activity and low alcohol
Engaging in more than 6 leisure activities lowers risk of dementia
Education, occupation, premorbid IQ and mental activities decreases risk
Support avaliable in treatment of dementia
- Socially active - talking to family and friends
- Cognitively active - cognitive stimulation programmes, board games etc.
- Specialist memory service
Medication that could be given in dementia
Acetylcholinesterase inhibitor in Alzheimer’s to increase ACh e.g. ORAL DONEPEZIL or ORAL RIVASTIGMINE
Blood pressure control to reduce further vascular damage, particularly in vascular dementia such as ACE-inhibitors e.g. RAMIPRIL
Differential diagnosis of dementia
Substance abuse, hypothyroidism, space-occupying intracranial lesions, Huntington’s
Clinical presentation of Alzheimers
Insidious onset with steady progression over years
Short-term memory loss is usually the most prominent early symptom
Subsequently there is slow disintegration of the personality and intellect, eventually affecting all aspects of cortical function
Decline in:
language (difficulty naming and in understanding what is being said)
visuospatial skills
apraxia (impaired ability to carry out skilled motor tasks)
agnosia (failure to recognise objects e.g. clothing, people and places)
Clinical presentation of Vascular dementia
- Stepwise deterioration with declines followed by short periods of stability
- History of TIA’s and or strokes
- Evidence of artheropathy
Clinical presentation of Lewy-body demetia
- Fluctuating cognition with pronounced variation in attention and alertness
- Prominent or persistent memory loss may not occur in the early stages
- Impairment in attention, frontal, subcortical and visuospatial ability is often prominent
- Depression and sleep disorders occur
- Visual hallucinations
- Parkinsons e.g. slowing and rigidity is common
- Loss of inhibitions
What are Lewy-bodies
Abnormal aggregates of protein that develop inside nerve cells, contributing to Parkinson’s disease (PD)
Describe the MMSE
Mini Mental State Examination (MMSE) commonly used to screen for cognitive function:
Score of 25 or above out of 30 is normal, 18-24 = mild/moderate impairment
Score of 17 or below indicates serious impairment
Diagnosis - generally
History - assess cognitive function by asking various questions
MMSE
Exclusion of rare treatable causes of dementia (substance abuse, vitamin
B12 deficiency, hypothyroidism) should be considered Blood tests: FBC, liver biochemistry, thyroid function tests and vitamin B12 and folate measurement
Neuropsychology
Brain CT in younger patients or those with atypical presentation MRI - to see extent of atrophy
Brain function can be assessed:
Energy and blood supply via PET & SPECT scanning
Brain networks via functional MRI