Medical Definition of Delirium & Dementia

Delirium and dementia are the most common causes of lack of mental functioning according to the Merck Manual. People with either or both of these disorders are unable to increase, retain, and use knowledge in the normal fashion. Delirium and dementia may occur together, but their medical definitions are quite different.

Delirium

• Delirium starts quite suddenly, causes changes in mental functioning, and is often reversible according to the medical definition. Delirium affects mainly attention. People with delirium are often disoriented, unable to think clearly, and may be hyper one minute and in a sleep-like state the next. There are many causes of delirium. It may occur at any age. It is more common in older people because of changes in the brain that occur with age. Delirium affects 15 percent to 50 percent of hospitalized people who are 70 or older, according to the Merck Manual. It is common among nursing home residents.

Dementia

• A person with dementia gets worse over time. The disease slowly progresses and is most often irreversible. Dementia usually affects a person's short-term memory first. The other problems that a person with dementia may have include difficulty with language, planning ahead and judgment, simple mathematical calculations, and movement according to the medical definition. Age is a common risk factor for dementia. As the disease progresses, mental functions deteriorate depending on what part of the brain is affected.

Diagnosis

• To make a diagnosis of dementia, delirium must be ruled out as a cause of the mental confusion. People who have dementia are at an increased risk of also having delirium. Delirium is a sudden onset of memory deficits and perception and may be treatable. Diagnosing delirium is based on observing a person suspected of having it. There are no specific diagnostic tests for delirium. The diagnosis is missed in more than 50 percent the of cases, according to Dr. John Burton of Johns Hopkins. The most common cause of delirium is dementia. It can be exacerbated if the person with dementia also has an infection, is in an unfamiliar environment, is taking certain medications or is in pain.

Prevention Of Delrium

• Most important in avoiding delirium is finding the root cause of it. The cause could be a serious disease of the liver, lungs, heart, brain, or kidneys to something simple like a strange environment. A thorough physical examination by a qualified medical professional is the first step in preventing delirium. Treat the root cause as soon as possible. Until you have determined the root cause, avoid the person using psychoactive drugs, have a quiet environment, involve the person in activities during the day, keep the environment dark and quiet at night, make sure the person wears glasses and other visual and hearing assistive devices as needed, and do not use restraints.

Prevention Of Dementia

• According to two studies in the August 12, 2009, issue of the American Medical Association, healthy long-term lifestyle habits may reduce the risk of mental decline in old age. The studies suggest that intellectual disorders are not totally controlled by genetics. Your lifestyle and other factors play a role in your risk for developing dementia.

  There is no vaccine that will prevent dementia, and there is no guarantee that healthy lifestyle habits will prevent dementia in everyone that practices them. Healthy lifestyle choices in regards to nutrition, diet, exercise, and mental and social activity can lower the risk of getting dementia and other cognitive disorders.