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Delirium is a change in mental status. It usually comes on quickly, over hours or days. Delirium is marked by extreme, fluctuating changes, including:

  • Changes in perception and sensation
  • Difficulties with ability to:
    • Focus
    • Sustain and shift attention
    • Think and reason rationally
    • Function normally
    • Communicate clearly


Hundreds of underlying causes can result in delirium. Some of the most common causes include:

Brain Tumor
Brain Tumor
Just one of many potential causes of delirium.
Copyright © Nucleus Medical Media, Inc.

Risk Factors

These factors increase your chance of developing delirium:

  • Terminal illness, especially just before death
  • Serious illness such as AIDS
  • Advanced age
  • Severe sleep deprivation
  • Severe burn
  • Central nervous system problems such as stroke , seizures , tumors or dementia
  • Surgery
  • Hospitalization
  • Visual or hearing impairment
  • Immobility
  • Dehydration
  • Severe constipation
  • Memory impairment
  • Deficiency in certain vitamins


Symptoms usually come on quickly and can last for days, weeks, or longer. They also vary in severity depending on the cause. Symptoms are often worse at night and may include:

  • Inability to pay attention
  • Confusion
  • Memory problems
  • Language disturbances
  • Disorientation, especially about:
    • Time of day
    • Where one is
    • Who one is

Severe symptoms include:

  • Misinterpretations—for example, thinking a doctor who is trying to help you is trying to hurt you
  • Illusions—for example, thinking someone is someone else
  • Hallucinations—seeing, hearing, or feeling things that are not there
  • Emotional disturbances—for example, suddenly becoming very angry, fearful, or withdrawn for no apparent reason


The doctor will ask about your symptoms and medical history. A physical exam will be done and the doctor will ask you questions. The doctor will ask specific questions about:

  • Present injury or illness
  • Use of medicines or illicit drugs
  • Time when mental state changed
  • How and how fast the mental state changed

The diagnosis will be made based on what the doctor finds during the exam. To determine a cause your doctor may need to run several tests such as:

  • Blood tests to:
    • Look for signs of infection
    • Examine electrolyte levels including sodium , potassium , and calcium
    • Determine oxygen levels in the blood
    • Determine blood glucose levels
    • Determine Level of vitamins such as vitamin B12 , folate , and thiamine
    • Assess the level of medication in the blood
    • Look for toxins or illicit drugs
  • Kidney and liver function tests
  • Thyroid function tests
  • Spinal tap —to look for signs of infection, inflammation, injury, and/or cancer in the brain or spine
  • Urine examination and culture—to look for signs of infection

Images of internal organs may also help to determine a cause. Images may be taken with:


Delirium is first treated by identifying and treating the underlying cause. Then, symptoms are treated through medicine, psychological management, and environmental and supportive intervention.

Treatments may include:


Drugs used to treat symptoms of delirium include:

  • High potency antipsychotic medicines
  • Benzodiazepines—used to treat delirium caused by alcohol withdrawal
  • Cholinergic medicines—used to treat delirium caused by anticholinergic medicines, which are used to treat stomach cramps and spasms in the intestines and bladder, among other conditions
  • Vitamins—given if the delirium is caused by low levels of vitamins

If you are taking medication that is worsening your confusion, you may be asked to stop these.

Psychological Management

Psychological therapy may help you:

  • Feel safer and more comfortable
  • Improve the ability to function
  • Calm down and feel less anxious

Environmental and Supportive Intervention

This type of treatment can be done by doctors, nurses, or caretakers. It can help you readjust to your surroundings and reducing anxiety. Examples of this intervention include:

  • Placing a clock and calendar in your room.
  • Darkening the room at night and providing natural light during the day time hours.
  • Maintaining a quiet, noise-free room.
  • Reminding you often of the day and time, where you are, and why you are there.
  • Placing familiar objects around you such as family photographs or objects from home.


A number of steps have been shown to help prevent delirium in hospitalized patients at risk for delirium. These steps include:

  • Using memory orientation aids
  • Listening to relaxation tapes
  • Doing very light exercise (when possible and if recommended by your doctor)
  • Using vision and hearing aids (when necessary)
  • Drinking plenty of fluids (to prevent dehydration )

Delirium is difficult to prevent because it has so many causes and it can come on suddenly.

Revision Information

  • Reviewer: Rimas Lukas, MD
  • Review Date: 09/2013 -
  • Update Date: 09/30/2013 -
  • American Psychiatric Association

  • National Institute of Mental Health

  • Canadian Psychiatric Association

  • Canadian Psychological Association

  • Delirium. EBSCO DynaMed website. Available at: . Updated May 12, 2013. Accessed June 11, 2013.

  • Gleason O. Delirium. American Academy of Family Physicians website. Am Fam Physician. 2003 Mar 1;67(5):1027. Available at: . Accessed June 11, 2013.