Delirium
Acute confusional state; Acute brain syndromeDelirium is sudden severe confusion due to rapid changes in brain function that can occur with physical or mental illness.
Confusion
Confusion is the inability to think as clearly or quickly as you normally do. You may feel disoriented and have difficulty paying attention, remembe...
Read Article Now Book Mark ArticleCauses
Delirium is most often caused by physical or mental illness and is usually temporary and reversible. Many disorders may cause delirium. Often, these disorders do not allow the brain to get oxygen or other substances. They may also cause dangerous chemicals (toxins) to build up in the brain. Delirium is common in the intensive care unit (ICU), especially in older adults.
Causes include:
- Alcohol or medicine overdose or withdrawal
- Drug use or overdose, including being sedated in the ICU
- Electrolyte or other body chemical disturbances
Electrolyte
Electrolytes are minerals in your blood and other body fluids that carry an electric charge. Electrolytes affect how your body functions in many ways...
Read Article Now Book Mark Article - Infections such as urinary tract infections, pneumonia, or meningitis
Urinary tract infections
A urinary tract infection, or UTI, is an infection of the urinary tract. The infection can occur at different points in the urinary tract, including...
Read Article Now Book Mark ArticlePneumonia
Pneumonia is a breathing (respiratory) condition in which there is an infection of the lung. This article covers community-acquired pneumonia (CAP). ...
Read Article Now Book Mark Article - Severe lack of sleep
- Poisons
- General anesthesia and surgery
- Autoimmune disease
Symptoms
Delirium involves a quick change between mental states (for example, from lethargy to agitation and back to lethargy).
Lethargy
Fatigue is a feeling of weariness, tiredness, or lack of energy.
Read Article Now Book Mark ArticleAgitation
Agitation is an unpleasant state of extreme arousal. An agitated person may feel stirred up, excited, tense, confused, or irritable.
Read Article Now Book Mark ArticleSymptoms include:
- Changes in alertness (usually more alert in the morning, less alert at night)
Changes in alertness
Decreased alertness is a state of reduced awareness and is often a serious condition. A coma is the most severe state of decreased alertness from whi...
Read Article Now Book Mark Article - Changes in feeling (sensation) and perception
- Changes in level of consciousness or awareness
- Changes in movement (for example, may be slow moving or hyperactive)
- Changes in sleep patterns, drowsiness
Drowsiness
Drowsiness refers to feeling more sleepy than normal during the day. People who are drowsy may fall asleep when they do not want to or at times whic...
Read Article Now Book Mark Article - Confusion (disorientation) about time or place
- Decrease in short-term memory and recall
- Disorganized thinking, such as talking in a way that doesn't make sense
- Emotional or personality changes, such as anger, agitation, depression, irritability, and overly happy
- Incontinence
Incontinence
Urinary (or bladder) incontinence occurs when you are not able to keep urine from leaking out of your urethra. The urethra is the tube that carries ...
Read Article Now Book Mark Article - Movements triggered by changes in the nervous system
- Problem concentrating
Exams and Tests
The following tests may have abnormal results:
- An examination of the nervous system (neurologic examination), including tests of feeling (sensation), mental status, thinking (cognitive function), and motor function
- Neuropsychological studies
The following tests may also be done:
- Blood and urine tests
- Chest x-ray
Chest x-ray
A chest x-ray is an x-ray of the chest, lungs, heart, large arteries, ribs, and diaphragm.
Read Article Now Book Mark Article - Cerebrospinal fluid (CSF) analysis (spinal tap, or lumbar puncture)
Cerebrospinal fluid (CSF) analysis
A CSF cell count is a test to measure the number of red and white blood cells that are in cerebrospinal fluid (CSF). CSF is a clear fluid that is in...
Read Article Now Book Mark Article - Electroencephalogram (EEG)
Electroencephalogram
An electroencephalogram (EEG) is a test to measure the electrical activity of the brain.
Read Article Now Book Mark Article - Head CT scan
Head CT scan
A head computed tomography (CT) scan uses many x-rays to create pictures of the head, including the skull, brain, eye sockets, and sinuses.
Read Article Now Book Mark Article - Head MRI scan
Head MRI scan
A head MRI (magnetic resonance imaging) is an imaging test that uses powerful magnets and radio waves to create pictures of the brain and surrounding...
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Treatment
The goal of treatment is to control or reverse the cause of the symptoms. Treatment depends on the condition causing delirium. The person may need to stay in the hospital for a short time.
Stopping or changing medicines that may worsen confusion, or that are no longer needed, may improve mental function.
Disorders that contribute to confusion should be treated. These may include:
- Anemia
Anemia
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Different type...
Read Article Now Book Mark Article - Decreased oxygen (hypoxia)
Hypoxia
Cerebral hypoxia occurs when there is not enough oxygen getting to the brain. The brain needs a constant supply of oxygen and nutrients to function....
Read Article Now Book Mark Article - Heart failure
Heart failure
Heart failure is a condition in which the heart is no longer able to pump oxygen-rich blood to the rest of the body efficiently. This causes symptom...
Read Article Now Book Mark Article - High carbon dioxide levels (hypercapnia)
- Infections
- Kidney failure
Kidney failure
Acute kidney failure is the rapid (less than 2 days) loss of your kidneys' ability to remove waste and help balance fluids and electrolytes in your b...
Read Article Now Book Mark Article - Liver failure
- Metabolic disorders
- Nutritional disorders
- Psychiatric conditions (such as depression or psychosis)
Depression
Depression may be described as feeling sad, blue, unhappy, miserable, or down in the dumps. Most of us feel this way at one time or another for shor...
Read Article Now Book Mark ArticlePsychosis
Psychosis occurs when a person loses contact with reality. The person may: Have false beliefs about what is taking place, or who one is (delusions)S...
Read Article Now Book Mark Article - Thyroid disorders
Treating medical and mental disorders often greatly improves mental function.
Medicines may be needed to control aggressive or agitated behaviors. These are usually started at very low dosages and adjusted as needed.
Some people with delirium may benefit from hearing aids, glasses, or cataract surgery.
Cataract surgery
Cataract removal is surgery to remove a clouded lens (cataract) from the eye. Cataracts are removed to help you see better. The procedure almost al...
Read Article Now Book Mark ArticleOther treatments that may be helpful:
- Behavior modification to control unacceptable or dangerous behaviors
- Reality orientation to reduce disorientation
Outlook (Prognosis)
Acute conditions that cause delirium may occur with long-term (chronic) disorders that cause dementia. Acute brain syndromes may be reversible by treating the cause.
Chronic
Chronic refers to something that continues over an extended period of time. A chronic condition is usually long-lasting and does not easily or quick...
Read Article Now Book Mark ArticleDementia
Dementia is a loss of brain function that occurs with certain diseases. It affects one or more brain functions such as memory, thinking, language, j...
Read Article Now Book Mark ArticleDelirium often lasts about 1 week. It may take several weeks for mental function to return to normal. Full recovery is usually expected, but depends on the underlying cause of the delirium.
Possible Complications
Problems that may result from delirium include:
- Loss of ability to function or care for self
- Loss of ability to interact
- Progression to stupor or coma
Stupor
Decreased alertness is a state of reduced awareness and is often a serious condition. A coma is the most severe state of decreased alertness from whi...
Read Article Now Book Mark ArticleComa
Decreased alertness is a state of reduced awareness and is often a serious condition. A coma is the most severe state of decreased alertness from whi...
Read Article Now Book Mark Article - Side effects of medicines used to treat the disorder
When to Contact a Medical Professional
Contact your health care provider if there is a rapid change in mental status.
Prevention
Treating the conditions that cause delirium can reduce its risk. In hospitalized people, avoiding or using a low dosage of sedatives, prompt treatment of metabolic disorders and infections, and using reality orientation programs will reduce the risk of delirium in those at high risk.
References
Inouye SK. Delirium and changes in mental status. In: Goldman L, Cooney K, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 361.
Mendez MF, Yerstein O. Delirium. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley's and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 4.
Central nervous system and peripheral nervous system - illustration
The central nervous system comprises the brain and spinal cord. The peripheral nervous system includes nerves outside the brain and spinal cord.
Central nervous system and peripheral nervous system
illustration
Brain - illustration
The major areas of the brain have one or more specific functions.
Brain
illustration
Central nervous system and peripheral nervous system - illustration
The central nervous system comprises the brain and spinal cord. The peripheral nervous system includes nerves outside the brain and spinal cord.
Central nervous system and peripheral nervous system
illustration
Brain - illustration
The major areas of the brain have one or more specific functions.
Brain
illustration
Review Date: 12/31/2023
Reviewed By: Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.