Mental Confusion or Delirium

Approved by the Cancer.Net Editorial Board, 04/2018

Delirium affects how a person thinks, remembers, and reasons. This is called a cognitive impairment disorder. The main signs of delirium are sudden changes in consciousness or state of arousal, such as feeling drowsy or agitated.

A person with delirium may experience confusion, disorientation, an inability to focus, memory problems, or changes in perception and behavior. These can include hallucinations or experiencing events that are not really happening.

Delirium is the most common sign of medical complications of cancer or cancer treatment affecting the brain and mind. It is a common problem for people with advanced cancer or those at the end of life. Because of its troubling symptoms, delirium is often very stressful for the person with cancer and his or her family members.

Delirium can make it harder for the health care team to assess and manage a person’s other symptoms. It can also interfere with a patient’s ability to receive cancer treatments.

Types of delirium

There are 3 types of delirium:

  • Hypoactive, meaning that the person acts sleepy or withdrawn

  • Hyperactive, meaning that a person is agitated

  • Mixed, meaning that a person alternates between these 2 types

More than two thirds of patients with delirium have the hypoactive or mixed type.

Symptoms of delirium

Symptoms of delirium include:

  • An altered level of consciousness or awareness

  • A shortened attention span

  • Memory problems

  • Disorganized thinking and speech

  • Disorientation

  • A reversal of day and night

  • Difficulty writing, drawing, or finding words

  • Personality changes

  • Depression

  • Delusions or hallucinations

  • Restlessness, anxiety, sleep disturbance, or irritability

Causes of delirium

Delirium often has more than one cause especially for people who are frail or severely ill. Medications are one of the main causes of delirium, but many other conditions can lead to delirium. Finding the cause of delirium is important to choose the best treatment.

The possible causes of delirium are described below.

Medications. Some medications used to treat cancer or manage other side effects can cause delirium. These include:

  • Chemotherapy

  • Pain medications

  • Medications to prevent nausea or treat allergies

  • Steroid medications

  • Sleep medications

  • New medications for other conditions

In addition, stopping some medications suddenly may cause symptoms of withdrawal, which can include delirium.

Organ failure. Problems in how some organs work can cause delirium. This can include liver and kidney failure. Heart and lung problems are also a potential cause. And seizures or cancer that has spread to the brain can cause delirium.

Fluid and electrolyte imbalances. Not having the correct balance of fluid and electrolytes in the body can cause delirium. There are several potential causes of these imbalances:

  • Hypercalcemia, which is too much calcium in the blood

  • Dehydration from not taking in enough fluids because of nausea, vomiting, or not being able to swallow comfortably. Dehydration can also be caused by loss of fluids through diarrhea and frequent urination.

  • Fluid overload, which can be caused by heart failure

  • Glucose disorders, which include hyperglycemia and hypoglycemia. Hyperglycemia is a high blood sugar level. This can be due to diabetes and worsened by cancer treatments. Or it can occur in people with no history of diabetes. Hypoglycemia is a low blood sugar level.

Infection. Bladder infections, pneumonia, a type of lung infection, and sepsis can cause delirium. Sepsis is a life-threatening condition caused from an infection that has spread to the bloodstream.

Lack of oxygen in the blood. Health problems that cause low levels of oxygen in the blood can lead to delirium. These include lung or heart problems, blood clots, and sleep disorders.

Diagnosing delirium

Doctors must do a physical exam and blood tests to find out whether a person is experiencing delirium. They will also do a mental status exam. This is done using tests that check motor skills, memory, and attention level. Your health care team may also recommend other tests, such as brain scans, based on the results of testing.

Managing delirium

The most effective treatment for delirium is to understand and treat the cause. Your doctor may use drug and non-drug approaches to manage delirium while keeping you comfortable and safe. It is important to work with your health care team to manage the symptoms of delirium. These tips may help:

  • Find a reassuring environment for yourself. This may include a quiet, well-lit room with familiar people and objects. It may also help to place a clock and wall calendar where you can see it.

  • Talk with your health care team about your hallucinations or unusual behaviors. They can help you learn what to expect and how to manage these symptoms.

  • Ask about stopping or switching medications that may worsen your mental confusion. Also, ask if there are other, untreated medical conditions that may be the cause of delirium.

  • In some cases, taking antipsychotic medications helps control the symptoms of delirium. These drugs cause side effects, but most can be managed well.

Relieving side effects is an important part of cancer care and treatment. This is called palliative care or supportive care. Talk with your health care team about any symptoms of delirium you experience. This includes any new symptoms or a change in symptoms.

Delirium at the end of life

Delirium at the end of life is common. Some believe that the hallucinations at the end of life are a part of the dying process and should not be treated as long as the hallucinations or delirium are not distressing to the person. For example, people who see dead family members welcoming them to an afterlife may find great comfort. But if the delirium is unpleasant or frightening to the person, treatment can be of great benefit.

Unpleasant delirium or delirium that causes other symptoms can be managed with several medications. These are often adjusted to help control the delirium but not interfere with the patient’s ability to interact with others.

Very rarely, a person with severe, agitated delirium that does not get better with treatment may need controlled sedation. Sedation is the use of drugs that put a patient into a deep sleep. This makes the person and his or her family more comfortable. However, it may leave family members with a premature sense of loss. Sedation is used to provide comfort to a person and his or her family at the end of life. It is not intended to speed up death. Even with sedation, a person may experience moments of clarity and talk with family members.

Each decision about managing delirium depends on you and your goals. It is important to talk with your health care team about all of the available treatment options. 

Related Resources

Care Through the Final Days

Side Effects