neurologic disorders
Dementia
Etiology of Dementia
Dementias may result from primary diseases of the brain or other conditions (see table). The most common types of dementia are Alzheimer Disease None Vascular Cognitive Impairment and Dementia None Dementia with Lewy Bodies and Parkinson Disease Dementia None Frontotemporal Dementia (FTD) None HIV-Associated Dementia None Dementia also occurs in patients with Dementia with Lewy Bodies and Parkinson Disease Dementia , Some structural brain disorders (eg, Normal–Pressure Hydrocephalus , Depressive Disorders None Age-associated memory impairmentrefers to changes in cognition that occur with aging. Older people have a relative deficiency in recall, particularly in speed of recall, compared with recall during their youth. These changes do not affect daily functioning and thus do not indicate dementia. However, the earliest manifestations of dementia are very similar. Mild cognitive impairment(MCI) causes greater memory loss than age-associated memory impairment; memory and sometimes other cognitive functions are worse in patients with this disorder than in age-matched controls, but daily functioning is typically not affected. In contrast, dementia impairs daily functioning. Up to 50% of patients with mild cognitive impairment develop dementia within 3 years. (SCD) is defined as a self-experienced persistent decline in cognitive capacity but normal performance on standardized cognitive tests used to classify MCI ( Etiology references ). The risk of MCI and dementia is increased in people with SCD. Variousdisorders may exacerbate cognitive deficits in patients with dementia. Delirium often occurs in patients with dementia. Medications,particularly benzodiazepines and anticholinergics (eg, some tricyclic antidepressants, antihistamines, antipsychotics,benztropine), may temporarily cause or worsen symptoms of dementia, as may alcohol or recreational drugs, even in moderate amounts. New or progressive kidney or liver failure may reduce medication clearance and cause toxicity after years of taking a stable dose (eg, ofpropranolol). Overview of Prion Diseases -like propagation mechanisms (RPD) is a group of heterogeneous cognitive disorders that progress faster than other dementia syndromes, typically within 1 to 2 years ( Etiology references ). The most prominent presentation is cognitive decline (eg, memory loss, visuospatial and language deficits, executive dysfunction). However, other neuropsychiatric symptoms (eg, behavior disturbance, personality change, mood disorders, psychosis, sleep disturbance, altered alertness and/or awareness, involuntary movements such as tremor and myoclonus, gait disturbance, seizure-like activities, ataxia, parkinsonian features) also occur. Prion disease is the most common cause of RPD. Other common causes include autoimmune and paraneoplastic encephalitis. Sometimes the progression of other dementias is atypically rapid; they include Alzheimer disease, dementia with Lewy bodies, frontotemporal dementia,and dementia due to potentially reversible causes (eg, infectious, toxic/metabolic, neurovascular, psychiatric). 1.Jessen F, Amariglio RE, Buckley RF, et al: The characterisation of subjective cognitive decline.Lancet Neurol19 (3):271–278, 2020. doi: 10.1016/S1474-4422(19)30368-0 2.Hermann P, Zen I: Rapidly progressive dementias — aetiologies, diagnosis and management.Nat Rev Neurol18 (6):363–376, 2022. doi: 10.1038/s41582-022-00659-0 