Definition

Delirium is a change in mental status. 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

Causes

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

• Serious medical condition such as a brain tumor, cancer, kidney failure, heart attack, stroke, seizures, and low or high blood sugar levels
• Serious infections, such as meningitis, pneumonia, and urinary tract infections
• Toxic effects of medications
• Injury such as severe head injury, broken bone, and severe pain
• Alcohol or drug abuse
• Withdrawal from alcohol or drug abuse
• Toxins

Risk Factors

Factors that may increase your risk of developing delirium include:

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

Symptoms

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• Emotional disturbances—for example, suddenly becoming angry, fearful, or withdrawn for no apparent reason

Diagnosis

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

• Present injury or illness
• Use of medications 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:

• Blood tests
• Urine tests
• Lumbar puncture
• Kidney and liver function tests
• Thyroid function tests

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

• Chest x-ray
• CT scan
• MRI scan

Electrical activity of the heart and brain can be tested with electrocardiogram (EKG) and electroencephalogram (EEG).

Treatment

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

Treatments may include:

Prevention

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 light exercise—when possible and if advised 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.

National Institute of Mental Health http://www.nimh.nih.gov

Canadian Psychological Association http://www.cpa.ca

Gleason O. Delirium. Am Fam Physician. 2003;67(5):1027-1034.