Key Points
- Dementia is a chronic, often irreversible decline in cognition, significantly affecting daily functioning
- Diagnosis is clinical; blood tests and imaging help to identify reversible causes. Acute confusion (delirium) is the main differential diagnosis
- Unlike age-related memory loss and mild cognitive impairment (MCI), dementia leads to cognitive impairments that interfere with everyday tasks
- Consider reversible causes like brain structural issues (e.g. normal-pressure hydrocephalus), metabolic disorders (e.g. hypothyroidism), medication side effects, depression, and toxins
- Treatment is mainly supportive; cholinesterase inhibitors may temporarily improve cognitive function.
1. Definition
- Dementia is a collective term for a range of brain disorders characterised by cognitive decline affecting memory, language, judgement, mood, personality, and physical coordination
- These impairments interfere with daily activities and impact patients and their caregivers socially, psychologically, and economically
- Alzheimer’s disease is the most common type, and while treatment may slow progression in some, dementia tends to worsen over time.
2. Epidemiology
- Dementia affects approximately 10% of those aged 80 and 20% of those aged 90, with over 1 million people in the UK living with the condition
- Women are twice as likely as men to develop dementia
- Although typically diagnosed in those over 65, it can occur at any age.
3. Risk factors
- Age: The most significant risk factor
- Gender: Women are at higher risk
- Genetics: Certain gene mutations (e.g. APP, PSEN1, PSEN2) are linked to familial Alzheimer’s disease, though this accounts for less than 5% of all cases. First-degree relatives have a 25-50% risk without a genetic mutation. ApoE4 is the most common genetic determinant in late-onset Alzheimer’s
- Medical history: Conditions such as multiple sclerosis, Huntington’s disease, Down’s syndrome, and HIV increase dementia risk
- Head injuries: Frequent trauma (e.g. in boxers) heightens the risk
- Mild cognitive impairment (MCI): About one-third of MCI patients progress to dementia within 3 years
- Learning disability: Approximately 20% of those over 65 with learning disability meet dementia criteria
- Other: Cardiovascular disease, cerebrovascular disease, and Parkinson’s disease (PD) also increase risk.
4. Causes
There are two main types of dementia:
- Alzheimer’s Disease: Caused by abnormal beta-amyloid protein build-up in the brain
- Vascular Dementia: Resulting from reduced blood flow to the brain, often due to strokes or TIAs.
Other forms include Lewy body dementia, frontotemporal dementia, and mixed dementia (a combination of different types). Accurate diagnosis is essential as dementia is not a normal part of ageing.
5. Symptoms
Dementia leads to a gradual, global cognitive decline.
- Early symptoms – such as memory loss, may initially resemble age-associated memory impairment or MCI but worsen over time
- Personality and behaviour – changes may develop
- Motor and neurological deficits – appear earlier in vascular dementia and later in Alzheimer’s
- Psychosis (hallucinations, delusions, paranoia) – affects about 10% of patients.
6. Diagnosis
Diagnosis is clinical, supported by tests and imaging (below) to rule out reversible causes.
Investigation
- Blood tests: FBC, U&E, LFTs, glucose, TSH, vitamin B12, folate
- Imaging: Chest x-ray and CT head.
Differential diagnosis
- Acute confusion (delirium): Rapid onset of disturbed consciousness, attention, and perception, usually resolves after treatment
- Normal age-related memory loss: Mild decline in cognitive function associated with ageing
- Mild cognitive impairment (MCI): Memory problems that do not yet interfere with daily life
- Other: Depression, vitamin deficiencies (B12, thiamine), hypothyroidism, toxins (e.g. lead), sensory deficits
- Other chronic neurological diseases – can occur as the same time (e.g. Parkinson’s Disease and depression). It’s important to treat them all.
7. Treatment
There is no cure for dementia. Treatment is aimed at managing symptoms and supporting patients and caregivers.
- Medications:
- Cholinesterase inhibitors: Donepezil, rivastigmine, galantamine
- NMDA receptor antagonist: Memantine
- Consider reversible causes, such as brain structural issues, metabolic disorders, or toxins
- Supportive care includes providing a safe, familiar environment and supporting caregivers.
8. Complications
- Malnutrition: Patients may stop eating, leading to nutritional deficiencies
- Pneumonia: Swallowing difficulties increase the risk of aspiration pneumonia
- Loss of independence: Patients struggle with self-care tasks (e.g. washing, dressing)
- Safety risks: Dementia patients may face dangers in daily activities like driving or cooking
- End stage: Late-stage dementia can lead to coma and death, often due to infections.
9. Prognosis
Dementia is usually progressive, with variable rates of decline depending on the cause. Life expectancy is typically shortened, though survival estimates vary widely.
10. Prevention
There are no guaranteed ways to prevent dementia, but some strategies may help delay onset:
- Mental stimulation: Reading, puzzles, and word games may help
- Physical and social activity: Aim for at least 150 minutes of exercise weekly
- Quit smoking: This may lower the risk of dementia
- Vitamin D: Low levels are linked to an increased risk of dementia
- Cardiovascular health: Manage hypertension, cholesterol, and diabetes
- Healthy diet: A Mediterranean-style diet may reduce the risk
- Hearing and visual Loss: Early treatment may reduce cognitive decline.
Additional support. GPs, specialists, and dementia nurses play a crucial role in managing dementia patients. Long-term monitoring, medication management, and connecting with support organisations (e.g. Alzheimer’s Society) are other key steps in ongoing care.
