Dementia
Dementia is a progressive, irreversible clinical syndrome with a range of cognitive and behavioural symptoms and reduction in the person’s ability to carry out daily activities.
This updated UKMLA guide to dementia covers various causes of dementia including Alzheimer’s disease, vascular dementia, dementia with Lewy bodies, and frontotemporal dementia, based on NICE NG97 and NICE CKS: symptoms, diagnosis, and management.
Causes and Types
Dementia is not a single disease entity; it is an umbrella term describing a clinical syndrome that can result from several underlying causes.
Main causes of dementia:
| Dementia cause / type | Prevalence | Description |
|---|---|---|
| Alzheimer’s disease | 50-75% of cases | Pathologically associated with:
Causing cerebral cortex atrophy |
| Vascular dementia | 20% of cases | Caused by cerebrovascular disease resulting in reduced blood supply to the brain. |
| Dementia with Lewy bodies | 10-15% of cases | Characterised by Lewy body deposition in the cortical and subcortical structures |
| Frontotemporal dementia | 2% of cases | Characterised by progressive degeneration of the frontal and/or temporal lobes |
Other causes include:
- Space-occupying lesions
- Other neurological conditions
- Normal pressure hydrocephalus
- Parkinson’s disease dementia
- Progressive supranuclear palsy
- Huntington’s disease
- Prion disease (e.g. CJD)
- Metabolic conditions
- Hypothyroidism
- Vitamin B12 deficiency
- Vitamin B1 (thiamine) deficiency
- Hypercalcaemia
- Uraemia (in renal impairment)
- Hepatic encephalopathy
- Adrenal insufficiency, hypopituitarism
- Infections
- HIV dementia
- Tertiary syphilis
Be aware of medications that can contribute to cognitive impairment
- Those with anticholinergic properties (e.g. TCA, anticholinergics used for overactive bladder, antihistamines, antipsychotics)
- Benzodiazepines
- Opioids
Risk Factors
General risk factors:
- Older age – strongest risk factor
- Mild cognitive impairment (~1/3 of those will develop dementia within 3 years)
- Learning disability
Cause / type-specific risk factors:
| Dementia type | Risk factors |
|---|---|
| Alzheimer’s disease | Genetic risk factors:
Down syndrome (trisomy 21) is a major risk factor for early-onset Alzheimer’s disease, as the APP gene is located on chromosome 21, and Down syndrome patients have 3 copies Modifiable risk factors (~1/3 of cases may be attributable to modifiable risk factors):
|
| Vascular dementia | Mainly contributed by cerebrovascular disorders
General cardiovascular risk factors also increase risk, including:
|
| Dementia with Lewy bodies |
|
| Frontotemporal dementia |
|
Clinical Features
Dementia has a gradual onset and non-specific signs and symptoms, which vary from person to person.
Non-Specific / Shared Clinical Features
Suspect dementia if ANY of the following are reported by the patient and/or family / carer:
| Category | Clinical features |
|---|---|
| Cognitive impairment | Impairment in any of the following domains
|
| Behavioural and psychological symptoms of dementia (BPSD) | BPSD are essentially non-cognitive symptoms
BPSD tend to fluctuate, and may last 6 months or more:
|
| Difficulties with activities of daily living (ADLs) | Examples include:
|
Type-Specific Clinical Features
| Dementia type | Specific clinical features |
|---|---|
| Alzheimer’s disease | Typical presenting symptom
Alzheimer’s disease often co-exists with other forms of dementia such as vascular dementia. |
| Vascular dementia | Patient would likely have a history of cardiovascular / cerebrovascular diseases (esp. stroke / TIA) and/or risk factors
Imaging may show old infarcts or small vessel disease. |
| Dementia with Lewy bodies | Core tetrad features:
Memory impairment may not be apparent in early stages Dementia with Lewy bodies vs Parkinson’s disease dementia They are closely related conditions within the spectrum of Lewy body disease, a textbook rule:
|
| Frontotemporal dementia | Typical onset in 60-69 y/o with family history
Other cognitive functions (such as memory and perception) may be relatively preserved |
Dementia Mimics
Dementia and delirium can both present with confusion, memory problems and impaired functioning:
| Feature | Dementia (non-advanced cases) | Delirium |
|---|---|---|
| Onset | Gradual onset | Acute / subacute onset |
| Course | Progressive decline over months to years | Fluctuating course over hours to days |
| Consciousness | Usually normal | Altered level of consciousness is common |
| Attention | Usually preserved | Impaired attention is a core feature |
| Orientation | Usually normal | Often impaired |
| Hallucinations | Mainly in dementia with Lewy bodies | Common, often visual hallucinations |
| Reversibility | Progressive and irreversible | Often reversible if the underlying cause is treated |
Key distinction: dementia is a chronic progressive cognitive disorder, whereas delirium is an acute fluctuating confusional state.
To distinguish between delirium and dementia, NICE recommends using the:
- Confusion assessment method (CAM)
- Observational Scale of Level of Arousal (OSLA)
If not possible to tell between delirium and dementia, or delirium superimposed on dementia → treat delirium first
Depression can cause cognitive symptoms that mimic dementia, sometimes referred to as pseudodementia
| Feature | Dementia | Depression / pseudodementia |
|---|---|---|
| Onset | Usually gradual and progressive | May be more clearly linked to a mood change or life event |
| Mood symptoms | Possible, but cognitive symptoms are usually the main concern | Low mood, anhedonia, hopelessness, poor sleep, appetite changes are often prominent |
| Cognitive complaints | Lack of insight into the cognitive symptoms is common | Patient often emphasises memory problems and may be very distressed by them |
| Effort during consultation / assessment | Good effort, often attempts answers but may be incorrect | Poor effort, may give “I don’t know” answers |
| Pattern of impairment | Progressive decline affecting daily function | Cognitive symptoms may fluctuate with mood and concentration |
Late-life depression may also be a risk factor for, or early feature of, underlying dementia.
Prognosis
Dementia is a life-limiting condition, there is no treatment currently available to cure dementia or stop disease progression
Dementia and Alzheimer’s disease are the leading cause of death for women (13.4% of deaths) and 2nd leading cause of death for men (7% of deaths)
Time from presentation to death (varies by age):
- Late 60s to early 70s = median lifespan of 7-10 years
- 90s = median lifespan of 3 years
Investigation and Diagnosis
For a diagnosis of dementia to be made, there must be impairment:
- In at least two of the following cognitive domains: memory, language, behaviour, visuospatial or executive function, and
- Which causes a significant functional decline in usual activities or work, and
- Which cannot be explained by delirium or other major psychiatric disorder
Early-onset (or young-onset) dementia is generally defined as dementia that develops <65 y/o
Mild cognitive impairment is cognitive impairment that does not fulfil the diagnostic criteria for dementia (e.g. only one cognitive domain is affected, or deficits do not significantly affect daily activities)
Primary Care
| Clinical assessment |
|
| Cognitive testing | NICE recommends the following validated cognitive assessment tool
|
| Blood tests | To exclude reversible causes of cognitive decline
Other investigations that may be appropriate if clinically indicated include urine microscopy and culture, chest X-ray, ECG, syphilis serology, and HIV testing |
If dementia is suspected and reversible causes have been investigated → refer to specialist dementia diagnostic service (e.g. memory clinic, community old age psychiatry service)
NICE did not specifically recommend the use of MoCA and MMSE which are still often used in practice. Expert summaries and reviews commented that:
- Longer or more complex tests may not be better than shorter simpler tools in primary care.
- MoCA is reported as not well tolerated by people with suspected dementia (ACNR Journal review) [Ref]
Secondary Care
Dementia and its subtypes can be diagnosed clinically by a specialist
Also include a test of verbal episodic memory if Alzheimer’s disease is suspected
Imaging
Offer structural imaging (usually MRI brain, alternatively CT) to rule out reversible causes of cognitive decline and assist with subtype diagnosis
- Unless dementia is well established and the subtype is clear
Consider further imaging if there is diagnostic uncertainty for the dementia subtype (and would change management):
| Suspected dementia subtype | Test of choice | Findings |
|---|---|---|
| Alzheimer’s disease | Either of the following:
|
Functional brain imaging:
CSF analysis:
|
| Lewy body dementia |
Do not rule out Lewy body dementia based on normal results |
DaT scan
Cardiac scintigraphy:
|
| Frontotemporal dementia | Functional brain imaging:
|
Reduced function in frontal and/or anterior temporal lobes:
|
| Vascular dementia |
|
Ischaemic white matter changes:
|
Clarification of some confusing terms – different types of SPECT imaging.
- SPECT is a general imaging technique
- 123I‑FP‑CIT SPECT is a specific type of SPECT where 123I‑FP‑CIT binds to dopamine transporters thus is also called DaT scan. This is used to assess dopaminergic activity and used for Lewy body dementia and Parkinsonian syndromes
- When NICE just mentions SPECT, they are referring to brain perfusion SPECT that uses tracers like technetium-99m which measures regional cerebral blood flow
Therefore, the SPECT mentioned in Lewy body dementia, Alzheimer’s disease and frontotemporal dementia are NOT interchangeable.
On the other note, PET scans assess glucose uptake and metabolism in tissue using 18F-FDG tracer.
Management
Conservative / General Management
Offer:
- Range of activities to promote wellbeing tailored to the patient’s preferences
- Group cognitive stimulation therapy (for mild to moderate dementia)
Consider the following for mild to moderate dementia:
- Group reminiscence therapy
- Cognitive rehabilitation or occupational therapy
Behavioural and Psychological Symptoms of Dementia (BPSD)
1st line: non-pharmacological interventions (psychosocial interventions, environmental adaptations, verbal/non-verbal de-escalation)
- Ensure reversible triggers have been ruled out / managed (e.g., pain, infection, delirium, adverse effects of medications)
2nd line: pharmacological interventions
- Short-term antipsychotic therapy
- Indication
- Unresponsive to non-pharmacological interventions AND
- At risk of harming themselves or others, OR
- Experiencing agitation, hallucinations, or delusions that are causing severe distress
- Indication
- Licensed options (AD/VD): haloperidol and risperidone (started under specialist supervision)
Antipsychotics carry a significant risk of cerebrovascular events (e.g. stroke) and increased mortality in people with dementia.
When used, they should be prescribed at the lowest effective dose, for the shortest possible duration, with regular review of ongoing need.
General Pharmacological Management
Pharmacological management depends on the type of dementia.
Alzheimer’s Disease
For mild to moderate disease:
- Step 1: AChE inhibitor (donepezil / galantamine / rivastigmine)
- Step 2: add memantine
Consider memantine monotherapy in:
- Severe Alzheimer’s disease on presentation, or
- Acetylcholinesterase inhibitors not appropriate
Lewy Body Dementia
NICE guideline focuses only on general dementia management and does not elaborate on a symptom-based management approach, which is particularly relevant for Lewy body dementia:
| Symptom | Pharmacological management |
|---|---|
| Neurocognitive (i.e. dementia) | Similar to Alzheimer’s management:
|
| Psychiatric |
|
| Motor (i.e. Parkinsonism) |
|
Antipsychotics should be avoided in Lewy body dementia (and Parkinson’s disease dementia), as they can precipitate motor symptoms.
In these cases, non-pharmacological strategies and cholinesterase inhibitors should be prioritised for neuropsychiatric symptoms before considering antipsychotics.
Vascular Dementia
The mainstay of management of vascular dementia is identification and control of vascular risk factors (including hypertension, hyperlipidaemia, and diabetes)
Do NOT routinely offer AChE inhibitor or memantine
Only consider if the patient has suspected comorbid:
- Alzheimer’s disease
- Lewy body dementia
- Parkinson’s disease dementia
Frontotemporal Dementia
The mainstay of management for frontotemporal dementia is symptomatic and supportive care (focused on non-pharmacological interventions and caregiver support)
Do not routinely offer AChE inhibitor or memantine
Dementia and Driving
If the patient has dementia and/or any organic syndrome affecting cognitive functioning
| Licence type | Recommendation |
|---|---|
| Group 1 vehicle (car / motorcycle) | May be able to drive but must notify the DVLA
|
| Group 2 vehicle (bus / coach / lorry) | Must not drive and must notify the DVLA
Licensing will be refused or revoked |