Significant abnormal changes in a person’s behavior can be indicators of many different physiological processes. Events that either directly or indirectly negatively impact on the higher functions of the brain can lead to changes in personality, memory, outlook, insight and interaction with other people and the local environment. Being able to correctly identify the type of change that has occurred in a person’s “mentation” can be critical in determining what course should be followed and whether or not meaningful recovery is possible. The terms dementia (or demented) and delirium (or delirious) are often confused by the typical person, but they could not be more different in terms of outcomes.
Defining Delirium
Delirium itself is a symptom that is often associated with a number of underlying disorders. It is typically defined as an acute (relatively rapid onset of hours to days), transient global disorder of thinking and behavior. It is also sometimes referred to as an acute state of confusion. Delirium can be brought on by a large number of underlying disorders including bladder infections, dehydration, altered blood electrolyte levels, medication side-effects, illicit drug use, alcohol withdrawal, and many others. Delirium can be present where the person is hyperactive, difficult to quiet, is hallucinating and other features, but it also can be present where the person is very drowsy or lethargic, non-cooperative, unable to concentrate, unwilling to follow commands.
Delirium can occur more frequently in the elderly population, especially in the hospital or nursing care setting. In many cases it is assumed that elderly patients are often confused, that they are typically suffering from delirium. This is far from the truth and could be a dangerous miscalculation. The presence of delirium in a hospitalized patient predicts a significant increase in the chance that the patient could die. Finding the underlying cause of a case of delirium (for example, incorrect medication use) and treating that cause in many cases will allow the delirium to abate.
Defining Dementia
Dementia is also an alteration in the cognitive abilities of the person; however, it typically appears in a very different manner and can have significantly different outward signs. Dementia often includes impairments of memory and other disorders including, for example, an inability to name common objects, a loss of the ability to perform a specific sequence of motor tasks, disturbances of language such as inability to remember words or how to use them appropriately. There are numerous diseases that cause dementia including Alzheimer’s disease, frontal lobe disorders, significant blood vessel disease in the brain, and many others.
One of the hallmark differences between dementia and delirium is the fact that dementia causes a change in the person’s behavior or thought processes gradually, over a period of months to years, often beginning with subtle signs that go unnoticed. And unfortunately for those suffering from dementia, the symptoms progressively worsen over time leading to greater and greater mental disability.
One of the most important sources of information in trying to distinguish between delirium and dementia in a person is information from family or caretakers. The people who have had the most contact with a person showing signs of significant alterations in thinking and behavior oftentimes can provide the clinical practitioner with important information in making the correct diagnosis. To learn more about the hallmarks and the differences between delirium and dementia visit the Merck Manual online.
Reference:
American Psychiatric Association; Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV).
Kenneth Rosen - I am a medical research doctor with more than 20 years of experience studying how the nervous system and skeletal muscle develop and ...
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