Dementia is a syndrome characterised by deterioration in cognition, resulting in impairment in the activities of daily living. Cognitive decline occurs in one or more cognitive domains.
The incidence of dementia doubles with every 6.3 year increase in age, from 3.9 per 1000 person-years at age 60-64, to 104.8 per 1000 person-years at age 90 and over.
The global number of individuals who lived with dementia increased from 20.2 million in 1990, to 43.8 million in 2016, and dementia was the fifth leading cause of death globally, accounting for 2.4 million deaths. It is thought that the number of people living with dementia will almost double every 20 years, reaching 75 million in 2030 and 131.5 million in 2050, with this increase predominantly affecting developing countries.
The majority of cases of dementia have degenerative and vascular causes. Other causes include infections, inflammatory diseases, neoplasm, toxic insults, metabolic disorders, and trauma.
An estimated 11% to 14% of dementias are caused by potentially reversible conditions; therefore, ruling out these conditions is of the utmost importance when considering a diagnosis of dementia.
A number of conditions can present in a similar way to dementia syndrome and need to be considered during the evaluation. These include delirium, depression, amnestic syndromes, aphasia, and normal ageing.
- Mild cognitive impairment (MCI)
- Alzheimer's dementia
- Vascular dementia
- Lewy body dementia
- Amnestic syndromes
- Frontotemporal dementia
- Parkinson's disease
- Huntington's disease
- Brain tumours
- Cushing's syndrome
- Primary hyperparathyroidism
- Acute intermittent porphyria
- Primary hypothyroidism
- Wilson's disease
- Vitamin B12 deficiency
- Traumatic brain injury
- Lyme disease
- Syphilis (late)
- Systemic lupus erythematosus
- Sjogren's syndrome
- Medication use
- Normal pressure hydrocephalus
- Creutzfeldt-Jakob disease
- Caring for people with dementia: a clinical practice guideline for the radiography workforce
- Dementia: assessment, management and support for people living with dementia and their carers
Alzheimer' s disease and other kinds of dementia
Caring for someone with dementiaMore Patient leaflets
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