Dementia
Summary
Dementia is a syndrome characterised by progressive decline in cognitive function (memory, reasoning, language, behaviour) sufficient to interfere with daily functioning. Alzheimer's disease is the most common cause (~60-70%), followed by vascular dementia, dementia with Lewy bodies, and frontotemporal dementia. Diagnosis involves excluding reversible causes, cognitive assessment, and often neuroimaging. Pharmacological treatments (acetylcholinesterase inhibitors, memantine) provide modest symptomatic benefit. Non-pharmacological interventions, carer support, and advance care planning are central to management.
Key Facts
- Definition: Acquired progressive cognitive impairment affecting function
- Prevalence: 7-8% of adults ≥65 years; doubles every 5 years after 65
- Common Types: Alzheimer's (60-70%), Vascular (20%), Lewy Body (10-15%), Frontotemporal (2-5%)
- Reversible Causes: B12, Folate, Thyroid, Depression, Normal Pressure Hydrocephalus
- Pharmacotherapy: Donepezil, Rivastigmine, Galantamine (AChEIs); Memantine (moderate-severe)
- Key Goal: Maintain function, quality of life, and dignity
Clinical Pearls
"Rule Out Reversible Before Diagnosing": Always check B12, Folate, TSH, and consider depression before diagnosing dementia.
"Dementia Type Matters for Management": Lewy Body dementia is exquisitely sensitive to antipsychotics (risk of severe parkinsonism). Frontotemporal dementia does not respond to AChEIs.
"Advance Care Planning Early": Discuss values, preferences, and lasting power of attorney early while the patient can participate.
Why This Matters Clinically
Dementia is one of the leading causes of disability and dependence in older adults. Early diagnosis allows planning, access to support services, and targeted management. Carers are at high risk of burnout and need support.
Prevalence
| Age Group | Prevalence |
|---|---|
| 65-69 | 2% |
| 70-79 | 6-8% |
| 80-84 | 15% |
| 85+ | 30-40% |
Demographics
| Factor | Details |
|---|---|
| Age | Strongest risk factor (doubles every 5 years after 65) |
| Sex | Slightly more common in women (Alzheimer's) |
| Trend | Increasing prevalence due to aging population |
Risk Factors
| Factor | Details |
|---|---|
| Age | Major non-modifiable risk factor |
| Family History | 2-3x risk if first-degree relative |
| Genetics | APOE ε4 (Alzheimer's); Autosomal dominant forms (APP, PSEN1, PSEN2) |
| Cardiovascular | Hypertension, diabetes, dyslipidaemia, obesity (especially midlife) |
| Lifestyle | Smoking, physical inactivity, low education |
| Depression | Associated with increased risk |
| Head Injury | Repeated TBI increases risk |
Modifiable Risk Factors (Lancet Commission)
- Hearing loss, social isolation, depression
- Hypertension, diabetes, obesity (midlife)
- Smoking, physical inactivity, excessive alcohol
- Air pollution
Alzheimer's Disease
Amyloid Hypothesis:
- Abnormal processing of amyloid precursor protein (APP)
- Accumulation of amyloid-beta (Aβ) plaques
- Neurofibrillary tangles (hyperphosphorylated tau)
- Neuronal loss, synaptic dysfunction
- Cholinergic deficit (basis for AChEI therapy)
Vascular Dementia
- Cerebrovascular disease (large vessel infarcts, small vessel disease)
- White matter hyperintensities, lacunar infarcts
- Strategic infarct dementia (thalamus, hippocampus)
- Cognitive dysfunction proportional to vascular burden
Dementia with Lewy Bodies
- Alpha-synuclein Lewy body accumulation in cortical neurons
- Overlap with Parkinson's disease dementia
- Cholinergic deficit (more pronounced than Alzheimer's)
- Dopaminergic dysfunction (parkinsonism)
Frontotemporal Dementia
- Tau or TDP-43 proteinopathies
- Selective frontal and temporal lobe atrophy
- Behavioural variant (frontal) or language variants (semantic, non-fluent)
Common Symptoms
Memory:
Language:
Executive Function:
Behaviour:
Function:
Signs by Subtype
| Type | Characteristic Features |
|---|---|
| Alzheimer's | Episodic memory loss, gradual onset |
| Vascular | Stepwise decline, executive dysfunction, vascular signs |
| Lewy Body | Fluctuation, visual hallucinations, parkinsonism, RBD |
| FTD | Behavioural/personality change, language impairment |
Red Flags
[!CAUTION] Red Flags — Atypical or Serious:
- Rapid decline (<6 months) → CJD, autoimmune, metabolic
- Focal neurological signs → Stroke, mass lesion
- Young onset (<65 years) → Genetic causes, FTD
- Gait disturbance + incontinence → NPH (potentially reversible)
- Early visual hallucinations → Lewy Body
Structured Approach
General:
- Appearance, hygiene, nutritional status
- Level of alertness
Cognitive Assessment:
- MMSE, MoCA, ACE-III
- Clock drawing, verbal fluency
Neurological:
- Parkinsonism (Lewy Body)
- Primitive reflexes (grasp, glabellar tap)
- Gait disturbance (NPH, vascular)
Mood:
- Depression screen (GDS)
Functional:
- ADL/IADL assessment
First-Line (All Patients)
| Test | Purpose |
|---|---|
| FBC | Anaemia, infection |
| U&E, Calcium, Glucose, LFTs | Metabolic causes |
| TFTs | Hypothyroidism |
| B12, Folate | Deficiency |
| Urinalysis | UTI (common cause of delirium) |
Neuroimaging
| Modality | Purpose |
|---|---|
| CT Head | Exclude mass, SDH, NPH; atrophy pattern |
| MRI Brain | Hippocampal atrophy (AD), WMH (vascular), frontal/temporal atrophy (FTD) |
| DAT Scan | Distinguish DLB from Alzheimer's |
| FDG-PET | Dementia subtype differentiation |
Cognitive Assessment Tools
| Tool | Notes |
|---|---|
| MMSE | Quick, widely used; ceiling effect |
| MoCA | Better for mild impairment, executive function |
| ACE-III | Detailed, multi-domain |
| 6-CIT | Brief screen |
Non-Pharmacological (All Patients)
- Cognitive stimulation therapy (CST)
- Reminiscence therapy
- Physical activity
- Occupational therapy
- Environmental modifications
- Carer education and support
- Advance care planning (LPA, ADRT)
Pharmacological
Alzheimer's Disease:
| Severity | Treatment |
|---|---|
| Mild-Moderate | AChEI (Donepezil, Rivastigmine, Galantamine) |
| Moderate-Severe | Memantine ± AChEI |
Vascular Dementia:
- Cardiovascular risk factor management
- No specific disease-modifying treatment
Lewy Body Dementia:
- AChEI (Rivastigmine preferred)
- Avoid antipsychotics (neuroleptic sensitivity)
Frontotemporal Dementia:
- AChEI NOT effective
- SSRIs for behavioural symptoms
BPSD Management
- First-line: Non-pharmacological approaches
- If pharmacological needed: Short-term, low-dose antipsychotics (increased mortality risk)
| Complication | Notes |
|---|---|
| Falls | Major cause of morbidity |
| Delirium | Superimposed on dementia; poor prognosis |
| Aspiration Pneumonia | Advanced dementia |
| Malnutrition | Forgetting to eat, swallowing problems |
| Pressure Ulcers | Immobility |
| Carer Burnout | High rates of depression, anxiety in carers |
| Abuse/Neglect | Vulnerable population |
Natural History
| Dementia Type | Median Survival |
|---|---|
| Alzheimer's | 8-10 years |
| Vascular | 3-5 years |
| Lewy Body | 5-8 years |
| FTD | 6-8 years |
Prognostic Factors
- Younger onset: Faster decline
- Severe functional impairment: Shorter survival
- Comorbidities: Increase mortality
- Recurrent falls, aspiration: Poor prognosis
Key Guidelines
-
NICE NG97: Dementia — assessment, management and support (2018)
-
NICE Technology Appraisals: Donepezil, rivastigmine, galantamine, memantine (TA217)
Landmark Trials
AD2000 (2004) — Donepezil
- Key finding: Modest cognitive benefit; no delay to institutionalisation
- Clinical Impact: AChEIs provide symptomatic benefit; manage expectations
FINGER Trial (2015) — Multidomain intervention
- Key finding: Multi-domain lifestyle intervention may prevent cognitive decline in at-risk elderly
- Clinical Impact: Supports lifestyle modification for prevention
Evidence Strength
| Intervention | Level | Key Evidence |
|---|---|---|
| AChEI for Alzheimer's | 1a | Cochrane reviews |
| Memantine for moderate-severe AD | 1a | Meta-analyses |
| CST | 1a | Cochrane review |
What is Dementia?
Dementia is a condition where your brain's ability to think, remember, and do everyday tasks gradually gets worse over time. It's not a normal part of aging.
What causes it?
Dementia is caused by damage to brain cells. The most common cause is Alzheimer's disease. Other causes include strokes (vascular dementia), changes in certain brain proteins (Lewy body and frontotemporal dementia).
What are the symptoms?
- Memory problems (especially recent events)
- Difficulty finding words
- Trouble with everyday tasks (cooking, managing money)
- Confusion about time and place
- Changes in mood or personality
How is it treated?
- Medications: Tablets (like donepezil) can help memory and thinking in some people
- Therapies: Cognitive stimulation, music, social activities
- Support: Help for you and your family from memory services, carers' groups
- Planning ahead: Making decisions about future care while you can
What to expect
- Dementia progresses over years, but everyone is different
- Support is available at every stage
- Focus on quality of life and maintaining abilities
When to seek help
See your doctor if you notice:
- Memory problems affecting daily life
- Difficulty with familiar tasks
- Confusion or disorientation
- Personality or behaviour changes
Primary Guidelines
- National Institute for Health and Care Excellence. Dementia: assessment, management and support for people living with dementia and their carers (NG97). 2018. nice.org.uk/guidance/ng97
Key Studies
-
Livingston G, Huntley J, Sommerlad A, et al. Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. Lancet. 2020;396(10248):413-446. PMID: 32738937
-
Courtney C, Farrell D, Gray R, et al. Long-term donepezil treatment in 565 patients with Alzheimer's disease (AD2000). Lancet. 2004;363(9427):2105-2115. PMID: 15220031
Further Resources
- Alzheimer's Society: alzheimers.org.uk
- Dementia UK: dementiauk.org
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate guidelines and specialists for patient care.