Summary
Dementia is a syndrome characterised by an appreciable deterioration in cognition resulting in behavioural problems and impairment in the activities of daily living. Decline in cognition is extensive, often affecting multiple domains of intellectual functioning. [1] [2]
The prevalence of dementia is approximately 1% at the age of 60 years, and doubles every 5 years, to reach 30% to 50% by the age of 85 years.
The majority of cases of dementia are caused by degenerative causes and by vascular causes. [3] [4] [5] Other causes include infections, inflammatory diseases, neoplasm, toxic insults, metabolic disorders, and trauma.
An estimated 10% to 20% of dementias are caused by potentially reversible conditions; therefore, ruling out these conditions is of the utmost importance when considering a diagnosis of dementia. [6]
A number of conditions can present in a similar way to dementia syndrome and need to be considered during the evaluation. These include mild cognitive impairment (MCI), delirium, depression, amnestic syndromes, aphasia, and normal ageing.
Differential diagnosis
- Common
- Uncommon
-
- Amnestic syndromes
- Aphasia
- Frontotemporal dementia
- Parkinson's disease
- Huntington's disease
- Brain tumours
- Cushing's syndrome
- Hypopituitarism
- Primary hyperparathyroidism
- Acute intermittent porphyria
- Primary hypothyroidism
- Hyperthyroidism
- Wilson's disease
- Vitamin B12 deficiency
- Traumatic brain injury
- Lyme disease
- Tuberculosis
- Syphilis (late)
- Systemic lupus erythematosus
- Sjogren's syndrome
- Sarcoidosis
- Medication use
- Toxin-induced
- Normal pressure hydrocephalus
- Creutzfeldt-Jakob disease
