Also known as acute brain syndrome, Delirium affects at least one in ten hospitalized patients, and is a common part of many terminal illnesses.

Delirium is sudden, severe confusion and rapid changes in brain function that happen with physical or mental illness. Because it involves a quick change between mental states, someone who suffers from delirium may jump from lethargy to agitation almost instantaneously.

Delirium is a type of disorder that is often characterized by confusion, disorientation, inattentiveness, illusions and hallucinations. In some cases delirium is the result from nervous system over activity. The delirious patient will often exhibits a reduced awareness of and responsiveness to the environment.

Causes of Delirium

Delirium is most often caused by physical or mental illness and is usually temporary and reversible. There are many disorders that cause delirium, including conditions or substances that deprive the brain of oxygen. Other causes include alcohol or sedative withdrawal, drug abuse, body chemical disturbances, infections, pneumonia, stroke, poisons and surgery.

The most often cause of delirium are metabolic disorders, accounting for 20-40% of all cases. This type of delirium is called metabolic encephalopathy and it usually results from organ failure. Severe dehydration and vitamin deficiencies are more mild cases but can also cause delirium. Drug abuse is responsible for up to 20% of delirium cases that result from drug overdose, side effects or drugs that are meant to cause a state of euphoria.

Symptoms of Delirium

Signs and symptoms of delirium usually appear in a short period of time and often fluctuate throughout the day. The primary signs and symptoms of delirium include the following factors:

  • Changes in sleep pattern
  • Emotional changes
  • Changes in perception
  • Decrease in short-term memory
  • Problems concentrating
  • Inability to stop speech or behavior
  • Incontinence


There are many tests and exams that may be performed to determine whether or not a person has delirium. An exam of the nervous system, tests of feeling and cognitive tests are often done. Motor function tests, CT scans, MRI scans, X-rays and blood level tests may also be required to successfully diagnose delirium.

Treatment of Delirium

Treatment of delirium will begin with recognizing the underlying cause and managing the symptoms. The goal of treatment is to control or reverse the cause of the symptoms. Sedatives or antipsychotic drugs may be necessary to reduce anxiety, hallucinations and delusions. If these drugs are given, the patient will most likely be in the hospital under close supervision due to the side effects the drugs may have. However, the most common approach to treating delirium is to find the cause and directly treat the cause. Identifying the cause will include a series of tests, including tests for disease. Identifying the cause will also allow the patient to live the life before he or she was delirious.

If you know someone who has delirium and has not seen a doctor, you should take him or her to the doctor immediately; there could be an underlying cause that needs immediate help.

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