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At our National Cancer Information Center trained Cancer Information Specialists can answer questions 24 hours a day, every day of the year to empower you with accurate, up-to-date information to help you make educated health decisions. We connect patients, caregivers, and family members with valuable services and resources.
Or ask us how you can get involved and support the fight against cancer. Some of the topics we can assist with include:
For medical questions, we encourage you to review our information with your doctor.
When the thought process is disturbed, or when a person has trouble thinking and acting like they normally do, they may be confused. Many things can cause confusion in cancer patients, including:
Confusion can start or get worse when the patient goes to a new place and may worsen at night (you might hear this referred to as sundowning). Usually the cause of the confusion can and should be treated.
Delirium is a mental state of severe confusion that usually happens suddenly. Most of the time, the cause of delirium can be treated. Other times, delirium may be permanent, such as toward the end of life because of problems like organ failure. Delirium can be caused by:
The three types of delirium are:
If a patient becomes confused or you suspect delirium, call the cancer team right away. The patient may need to be seen quickly so the cause of the problem can be found and treated. Sometimes, the patient may need to be in the hospital until the problem is treated. During this time, it’s helpful for confused patients to have someone they know stay with them. Here are some of the things to watch out for:
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
Brant JM, Stringer LH. Cognitive impairment. In Brown CG, ed. A Guide to Oncology Symptom Management. 2nd ed. Pittsburgh, PA: Oncology Nursing Society; 2015:203-228.
Cancer.Net. Mental confusion or delirium. 2018. Accessed at https://www.cancer.net/coping-with-cancer/physical-emotional-and-social-effects-cancer/managing-physical-side-effects/mental-confusion-or-delirium on August 7, 2019.
Irwin SA, Pirrello RD, Hirst JM, Buckholz GT, Ferris FD. Clarifying delirium management: Practical, evidence-based, expert recommendations for clinical practice. Journal of Palliative Medicine. 2013; 16(4):423-435.
National Cancer Institute (NIH). Delirium (PDQ®)- Patient Version. 2019. Accessed at https://www.cancer.gov/about-cancer/treatment/side-effects/memory/delirium-pdq on August 7, 2019.
Nolan C, DeAngelis LM. The confused oncologic patient: A rational clinical approach. Current Opinion in Neurology. 2016; 29(6):789-796.
Last Revised: October 27, 2021
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