Delirium (sometimes called acute confusional state) and dementia are the most common causes of cognitive impairment, although affective disorders (eg., Depression) can interfere with cognitive massive. Delirium and dementia are different disorders, but that can be difficult to distinguish from each other sometimes. In both cognition is impaired; However, following this helps to distinguish: delirium affects mainly attention. Dementia primarily affects the memory. Other characteristics also help to distinguish the two disorders (see Table: Differences Between Delirium and Dementia *). A Dellir is usually caused by an acute illness or drug or drug toxicity (sometimes fatal) and is often reversible. Dementia is usually caused by anatomical changes in the brain shows a slow start and is usually irreversible. Delirium often develops in patients with dementia. The confusion of delirium and dementia in an elderly patient-a common clinical-error must be avoided, v. a. when the delirium superimposed on chronic dementia. No technical investigation can definitely clarify the cause of cognitive impairment; a thorough history and physical examination as well as the knowledge of the initial situation are essential. Differences between delirium and dementia * feature delirium dementia start suddenly, with a defined beginning slowly and gradually, eg with uncertain initial point of time from days to weeks, but possibly longer Normally permanently cause almost always another disorder (. As infection, dehydration, use or withdrawal of certain Pharm edium / drugs) Usually, a chronic disease of the brain (eg. As Alzheimer’s dementia, dementia with Lewy bodies, vascular dementia) course usually reversible Slowly progressive effect at night is almost always worse often worse Attention-affected Unaffected until the dementia was severely consciousness level variable affected Unaffected until the dementia schwe r was orientation regarding. Time and place varies Impairs use of language slowly, often incoherent and inappropriate Sometimes difficulties to find the right word memory Varies Lost, v. a. in view of recent events need to see a doctor immediately required, but less urgent * differences are real and diagnosis usually helpful, but exceptions not rare. For example, a traumatic brain injury occurs suddenly, but it can be severe, lasting cause dementia; Hypothyroidism can produce slowly progressive image of dementia, but to be completely reversible under treatment.