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Confusion and delirium affect how a person thinks and behaves. When someone is confused or delirious, they can't think clearly and might not behave like they usually do. It most often goes away, but can be a sign that something serious is wrong.
Confusion means a person can’t think clearly. People who are confused may think more slowly. They can have trouble focusing and understanding what’s going on around them. Confusion might last for a short time or can continue for longer.
Delirium affects memory and thinking. It is a more severe kind of confusion. It changes the way a person behaves and sees the world around them. Delirium comes on quickly and will often resolve after the cause is treated.
There are three types of delirium:
Many things can cause confusion and delirium in people with cancer. Often there is more than one cause. Some things that can lead to confusion and delirium are:
Confusion and delirium also happen more often in people who:
The first symptom of confusion or delirium is often a sudden change in how alert a person is. They might become very sleepy and out of touch with what’s going on around them. Or they might start to act very upset and nervous. Most often, the person will not be aware of these changes, but their family members or cancer care team will notice them.
Other symptoms might include:
These symptoms can come and go. They can get worse at certain times, such as at night, or if the person is in a new place.
Delirium may cause hallucinations. People may see, hear, smell, or feel things that others cannot. But the hallucinations feel real to the person with delirium. People with delirium may also have delusions, believing things that are not based in reality. For instance, they might believe that someone is trying to harm them when that person is only trying to help.
Treatment for delirium and confusion depends on the cause. Many times, treating the cause will ease or get rid of delirium or confusion. The cancer care team will do an assessment to look at any physical causes or medicines that might be causing the confusion or delirium. They may also want to do some tests, such as blood work, to try and find the cause.
Not all causes of delirium and confusion can be treated. This is often true when a person is nearing the end of their life. In that case, making the person comfortable may be the best option.
To get treatment started as soon as possible, the person with cancer or their caregiver needs to let the cancer care team know right away about changes.
Caring for someone who is confused or has delirium can be hard. Changes in how they behave might make family and friends anxious or afraid.
The type of care that your loved one needs will depend on how confused they are and other symptoms they may have. Here are some things you can do to help keep your loved one safe and as comfortable as possible.
Make sure you know who to call on your loved one's cancer care team and how to reach them, including when the office or clinic is closed.
Call the cancer care team as soon as possible if your loved one:
Many people have confusion and delirium at the end of their life. Some people believe that hallucinations at the end of life are part of the dying process. Treatment may not be needed if the hallucinations are not upsetting. For example, people may see family members or friends who have already died. This can be comforting. But if the hallucinations are scary, treatment can help.
There are medicines that can make a person with confusion or delirium more comfortable. The cancer care team may suggest sedation if a person is very agitated and not getting better with other treatments. Sedation can make the person who is dying more comfortable.
Deciding how to treat confusion or delirium depends on what the person with cancer would like. If possible, people should talk with their cancer care team about their treatment options ahead of time and think about putting their health care wishes in writing.
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
American Society of Clinical Oncology. Mental confusion or delirium. Accessed at cancer.net. Content is no longer available.
Cleveland Clinic. Confusion. Clevelandclinic.org. Accessed at https://my.clevelandclinic.org/health/symptoms/25206-confusion on December 7, 2023.
El Majzoub I, Abunafeesa H, Cheaito R, Cheaito MA, Elsayem AF. Management of altered mental status and delirium in cancer patients. Ann Palliat Med. 2019;8(5):728-739. doi:10.21037/apm.2019.09.14
Desimini EM. Altered mental status. In: Bush NJ & Gorman LM, eds. Psychosocial Nursing Care Along the Cancer Continuum. Oncology Nursing Society; 2018: 183-201.
National Cancer Institute. Delirium: Cancer Treatment Side Effect . Cancer.gov. Accessed at https://www.cancer.gov/about-cancer/treatment/side-effects/memory/delirium-pdq on December 1, 2023.
Francis J & Young GB. Diagnosis of Delirium and Confusional States. In, UpToDate, Post TW (Ed), UpToDate. Accessed at uptodate.com on December 5, 2023.
Last Revised: March 13, 2024
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