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Reversible Cognitive Disorder - Delirium

Rudolph C. Hatfield, PhD., edited by Kathryn Patricelli, MA

hospital room Delirium is a condition that is most often caused by some physical process where a person suddenly has a decline in their mental functioning. This is also sometimes referred to as an acute confusional state. Many people often display:

  • problems with attention
  • a rise and fall in their awareness (consciousness)
  • behaviors that are very unorganized and may appear similar to those that occur in dementia.

In the DSM-5 before diagnosing delirium in any person, a clinician must first diagnose the presence of a neurocognitive disorder. The DSM - 5 specifies:

  • Mild neurocognitive disorder as occurring when the person has problems with thinking that do not significantly affect their ability to function in their daily routine.
  • Major neurocognitive disorder as occurring when the person has problems with their thinking that does significantly affect their ability to function in their daily routine.

Delirium is diagnosed after a person is diagnosed with either minor or major neurocognitive disorder and then fits other specific conditions.

The Diagnosis of Delirium according to the DSM-5

After the clinician determines the presence of a neurocognitive disorder in the person, the clinician looks at the person's symptoms to determine the cause. According to the DSM-5, the symptoms of delirium include:

  • Problems with attention and awareness: Problems with attention can include issues with focusing, maintaining, or shifting their attention. Problems with awareness are defined as reduced orientation to the environment. This means that people with delirium typically have problems knowing where they are, knowing the date, recognizing people that they know, understanding their situation, etc.
  • A relatively fast onset: The problems that the person displays will most often happen over a short period of time. These changes often happen within a few hours or a few days and represent a significant change from the person's normal level of functioning. In addition, the person often displays changes in their symptoms depending on the time of day. This is often referred to as a fluctuating course. Most often, people are better in the morning and get worse as the day goes on.
  • An additional disturbance in cognition (thinking): In addition to the above symptoms, the person must also display some other disturbance in their thinking such as problems with memory, language, visual spatial abilities, etc.
  • Evidence of some physical cause: There is evidence from an exam or lab test that there is some possible physical cause to the person's issues.
  • No evidence of some other potential pre-existing cause: The delirium cannot be better explained by some other condition such as being in a coma due to head injury, due to some other mental disorder, etc.

Doctors can use many approaches to diagnose delirium. These can include:

  • lab tests such as blood and urine tests
  • brain scans
  • reports from the person's friends or relatives regarding how the symptoms appeared and how they are displayed.

Most often the main factor in diagnosing delirium is recognizing that the symptoms happened relatively quickly after the person began a new medication, had an infection or a disease, used drugs or alcohol, etc. When an otherwise relatively normal functioning person suddenly becomes confused and displays the symptoms listed above delirium is often suspected. However, in elderly people who may already have cognitive problems, the diagnosis of delirium may be overlooked.

Causes of Delirium

There are many possible causes of delirium. The DSM-5 lists only a few of these, but they can include:

  • Intoxication due to drugs or alcohol.
  • Withdrawal from drugs or alcohol.
  • Side effects due to medication use.
  • Other medical conditions.
  • More than one cause of symptoms that interacts with each other.

The potential happens for nearly any drug to cause delirium in elderly people or in people who have other medical conditions or mental disorders. Medical conditions that affect the person's metabolism such as infections, drug interactions, or problems with an individual's bodily regulation of hormones, neurotransmitters, etc. are common potential causes of delirium.

Although most sources report that delirium is short term, this is not always true. In some cases, people may have had delirium for only a few hours or a few days. In other cases, people may have had delirium for weeks to several months or more. In addition, many sources only describe the hyperactive type of delirium where the person is very active, agitated, or uncooperative with medical personnel. Delirium can also be hypoactive where the person is very sluggish, appears sleepy, and lacks energy. In some cases, people may have delirium that goes back and forth between hyperactivity and hypoactivity.

How Common Is Delirium?

According to the DSM-5, delirium is most common in people who are admitted to the hospital or who are in a hospital setting. Delirium occurs in:

  • About 1%-2% of people living within the community, but may be as high as 14% in people over the age of 85.
  • About 10%-30% of older people who are admitted to emergency room departments.
  • About 6%-56% of everybody in a hospital.
  • About 15%-53% of older people who are recovering from surgery.
  • About 70%-87% of people in intensive care (particularly older people).
  • As much as 60% of individuals living in nursing homes.
  • And up to 83% of individuals who are nearing death.

Is Delirium Reversible?

In a good number of cases the effects of delirium can be reversed to some extent. The cause of the person's delirium must be discovered, corrected, and then most often the symptoms of delirium will decrease. However, the effects of delirium may not always be fully reversible. If a person has had delirium for an extended period, this may have resulted in changes in the person's brain that cannot be completely reversed. The length of time a person has delirium is often related to the level of recovery that they will experience.

Other factors can also affect the symptoms of delirium. If a person suffers from delirium due to drugs or medication use, there may have been changes in the brain that do not fully reverse themselves once the drug has been discontinued. In many cases, people who have some form of dementia are extremely vulnerable to developing delirium. Even if the delirium is reversed, the person's dementia will not be reversed. People with dementia who are more vulnerable to delirium may be more vulnerable to damage to their brains because of having delirium.



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