Dementia
The term "dementia" refers to a decline in cognitive function. Dementia is not a disease itself but rather a description of a set of symptoms that can be caused by several different diseases or injuries. Dementia generally affects several areas of brain function including memory, attention, language and problem solving. A small number of cases of dementia can be reversed depending on the cause. Careful evaluation is necessary to identify the cause of dementia.
Higher mental functions (e.g., complex problem solving) are usually affected first in the process. In the later stages of the condition, affected persons may be disoriented in time (not knowing what day of the week, day of the month, month, or even what year it is), in place (not knowing where they are), and in person (not knowing who they are or others around them).
Symptoms of dementia can be classified as either reversible or irreversible, depending upon the etiology of the disease. Less than 10 percent of cases of dementia are due to causes which may presently be reversed with treatment. Causes include many different specific disease processes, in the same way that symptoms of organ dysfunction such as shortness of breath, jaundice, or pain are attributable to many etiologies. Without careful assessment of history, the short-term syndrome of delirium can easily be confused with dementia, because they have many symptoms in common. Some mental illnesses, including depression and psychosis, may also produce symptoms which must be differentiated from both delirium and dementia.
Delirium
Delirium is an acute and relatively sudden decline in attention-focus, perception, and cognition. Delirium is not the same as dementia (the two entities have different diagnostic criteria), though it commonly occurs in demented patients.
Delirium may be of a hyperactive variety manifested by 'positive' symptoms of agitation or combativeness, or it may be of a hypoactive variety (often referred to as 'quiet' delirium) manifested by 'negative' symptoms such as inability to converse or focus attention or follow commands. While the common non-medical view of a delirious patient is one who is hallucinating, most people who are medically delirious do not have either hallucinations or delusions. Delirium is commonly associated with a disturbance of consciousness (e.g., reduced clarity of awareness of the environment). The change in cognition (memory deficit, disorientation, language disturbance) or the development of a perceptual disturbance, must be one that is not better accounted for by a pre-existing, established, or evolving dementia. Usually the rapidly fluctuating time course of delirium is used to help in the latter distinction.
Delirium itself is not a disease, but rather a clinical syndrome (a set of symptoms), which result from an underlying disease or new problem with mentation. Like its components (inability to focus attention, confusion and various impairments in awareness and temporal and spatial orientation), delirium is simply the common symptomatic manifestation of early brain or mental dysfunction (for any reason).
Without careful assessment, delirium can easily be confused with a number of psychiatric disorders because many of the signs and symptoms are conditions present in dementia, depression, and psychosis. Delirium is probably the single most common acute disorder affecting adults in general hospitals. It affects 10-20% of all hospitalized adults, and 30-40% of elderly hospitalized patients and up to 80% of ICU patients.
Treatment of delirium requires treatment of the underlying causes. In some cases, temporary or palliative or symptomatic treatments are used to comfort patients or to allow better patient management (for example, a patient who, without understanding, is trying to pull out a ventilation tube that is required for survival).
Etiology of Dementia
Alzheimer's disease is the most common cause of progressive dementia accounting for about 60% of all cases. There are a number of other illnesses that can result in symptoms of dementia. Some of these include: Vascular Dementia (multiple strokes) Korsakoff's Disease, Huntington's Disease (also Huntington's Chorea), Picks Disease and Creutzfeldt-Jakob disease (human spongiform encephalitis).
Vascular dementia
Vascular dementia, also known as vascular cognitive impairment, is second only to Alzheimer's Disease in cases of dementia in the elderly population. Vascular dementia is caused by an interruption of blood flow to the brain often caused by mini-strokes. Some symptoms of vascular dementia are as follows: 1) memory problems 2) slurred speech 3) emotional lability 4) loss of concentration 5) difficulty handling money 6) dizziness 7) wandering.
Korsakoff's Disease
Wernicke's encephalopathy is a degenerative brain disorder caused by the lack of thiamine (vitamin B1). It may result from alcohol abuse, dietary deficiencies, prolonged vomiting, eating disorders, or the effects of chemotherapy. Symptoms include mental confusion, vision impairment, stupor, coma, hypothermia, hypotension, and ataxia. Korsakoff's amnesic syndrome-a memory disorder-also results from a deficiency of thiamine, and is associated with alcoholism. The heart, vascular, and nervous system are involved. Symptoms include amnesia, confabulation, attention deficit, disorientation, and vision impairment. The main features of Korsakoff's amnesic syndrome are the impairments in acquiring new information or establishing new memories, and in retrieving previous memories. Although Wernicke's and Korsakoff's may appear to be two different disorders, they are generally considered to be different stages of the same disorder, which is called Wernicke-Korsakoff syndrome. Wernicke's encephalopathy represents the "acute" phase of the disorder, and Korsakoff's amnesic syndrome represents the "chronic" phase.
Huntington's Disease
Huntington's Disease is a degenerative genetic disease which affects both physical and mental function. The gene that causes Huntington's has been isolated so although the disease can be detected there currently is not a cure. The physical symptoms of Huntington's are uncontrolled movements, slurred speech and difficulty swallowing. The cognitive symptoms can include memory loss, irritability, emotional lability, difficulty with decision making.
Creudzfeldt Jacobs disease
Creudzfeldt Jacobs disease (CJD) is a very rare disease which is fatal and causes rapid dementia. Some of the symptoms of CJD include speech impairment, personality change, and coordination problems. CJD is the human corollary of Bovine Spongiform Encephalitis (BSE) also called "mad cow disease."