Delirium: In the Hospital or After Surgery (2023)

Many patients are confused after having surgery, but delirium is a specific type of confusion that can take place in the hospital and during a recovery from surgery.While delirium causes confusion, not all confusion is caused by delirium.

Delirium is a state of altered and fluctuating mental functioning that occurs abruptly.It is typically acute—once diagnosed and treated, the patient will over time return to their normal mental state.

Delirium: In the Hospital or After Surgery (1)

Risk Factors

While anyone can develop delirium, certain groups are much more likely to develop delirium in the hospital.Age plays a role, but the severity of the current illness, the patient’s normal level of day to day function and the overall health of the patient play a part as well.

Risk factors include:

  • Age 65 years or older
  • Cognitive impairment, which includes difficulties with memory, concentration, and orientation
  • Alzheimer’s disease or other dementia
  • Severe illness or multiple illnesses
  • Depression
  • Impairment of hearing or vision
  • Multiple medications
  • Medications such as benzodiazepines, anticholinergics, antihistamines, or antipsychotics
  • Electrolyte abnormalities, such as too much or too little sodium
  • Pain that isn’t well controlled
  • Restraints or other things that interfere with movement, such as catheters
  • Too little oxygen or too much carbon dioxide
  • Sleep deprivation
  • Surgery
  • Anesthesia
  • Dehydration
  • Anemia
  • Alcohol abuse
  • Withdrawal from alcohol or other addictive substances

As you can imagine, an elderly patient with dementia who requires intensive care is at significantly more risk than a young adult with no additional risk factors who is in a private room in the hospital.

Intensive care units, in particular, are very disruptive to normal sleep/wake cycles, as the patients are experiencing frequent monitoring, frequent medications, are routinely being turned, are receiving more medications, and are often inrooms that are brightly lit around the clock.

In intensive care, you may hear delirium referred to as “ICU delirium.” It is most common in older adults and the elderly but can happen in any age group.It is also more common in people with some type of cognitive problem such as dementia.These elderly adults with dementia have the highest risk of experiencing a sudden decline in their mental capacity while in the hospital.

Early Signs

Before a patient begins to show signs of delirium, there is an earlier phase that patients can experience for hours or even days prior.During this time frame, patients may report extremely vivid dreams, difficulty sleeping, a heightened state of fear or anxiety that wasn’t present before, and may start to request the constant presence of another in their room.

Spotting these signs early can mean earlier intervention and potentially preventing the patient from experiencing full-blown delirium in the coming days.


There is no test for delirium. It cannot be diagnosed through lab work, although lab tests may help determine causes of delirium such as infections or metabolic disturbances. It must be diagnosed by observing the behavior of the patient and determining if their behavior fits the diagnosis of delirium.

(Video) Post Operative Delirium

Diagnosing delirium can be a challenge as it can be very different from patient to patient.

In general, people with delirium may have difficulty concentrating on a single topic, are disoriented, and often have a reduced or fluctuating level of consciousness.Their disorientation and mental difficulties are often worse at night, a condition sometimes referred to as “sundowning.”

Hallucinations and Delusions

People with delirium may experience delusions and hallucinations.

Delusions are fixed, false beliefs that are not changed by evidence.For example, a patient with delirium may believe that the nurse is trying to assassinate them.

Hallucinations are altered perceptual disturbances.A patient may see bats flying around the room and watch them fly from corner to corner.They may reach out and try to touch something that isn’t there or talk to someone who is not present or even someone who has died.

Physical Signs

People with delirium may have changes in sleep/wake cycles, such as being wide awake in the middle of the night or asleep during the day. They may show a decrease in appetite, difficulty speaking clearly and coherently, restlessness, or difficulty with posture.

These signs and symptoms have to be taken as a group, not individually. A person who suddenly starts fidgeting doesn’t necessarily have delirium, but a patient who cannot sit still, cannot speak coherently, is seeing things that aren’t there, and is uncharacteristically sleepy during the day might.


Delirium can present as hyperactive (overactive) or hypoactive (underactive):

Hyperactive delirium causes agitation. The person with delirium may be wide awake, to the point of being unable to sleep for days, and may seem like they are on high alert. They may seem wound up or restless, as though they have had too much caffeine.This behavior is often odd in the context of their hospitalization—they are wide awake when one would be expected to want to rest as much as possible.

Hypoactive delirium patients may seem lethargic, too tired to tolerate activity, depressed, sleepy, and may not be able to engage in conversation. This type is often more difficult to distinguish from being sick and tired than the more active type.

Why It’s More Common After Surgery

Delirium is seen more frequently in surgery patients than the general population of the hospital for multiple reasons. These patients tend to be sicker than average, they receive anesthesia medications that can contribute to delirium, they may be in the hospital longer, and they may receive pain medications and other drugs that can worsen delirium.


Environmental and Supportive Measures

Aside from helping a patient obtain the quality sleep that they desperately need, patients with delirium will also need support taking care of the basic and essential needs that they cannot manage while ill.

(Video) Experiencing delirium after surgery

When a patient has delirium, it is important that the staff of the hospital (as well as family and friends who may visit) help to provide the patient with the essentials that they need most.These essentials include uninterrupted sleep, eating and drinking regularly, taking care of bathroom needs and routinely reorienting the confused patient.

Frequent reorientation means simply gently letting the patient know that they are in the hospital, why they are there and what day and time it is.For family and friends, it is very important not to argue with a patient who is confused or experiencing delusions or hallucinations.You may gently attempt to reorient the patient to where they are and why, but arguing will only upset the patient and the family member.

It is also important not to wake the patient when they are sleeping unless it is absolutely essential, and staff may choose to omit a vital sign check or a middle of the night medication that can wait until morning if it means allowing the patient to sleep. Some facilities provide earplugs and eye masks to patients in order to increase their quality of sleep by blocking out the constant light and noise.

If the patient cannot be alone without risking an injury due to falling out of bed or other activities, family, friends, or hospital staff will likely need to be in the room at all times.


Identifying the underlying cause of delirium is key to treatment.If a medication is causing the problem, stopping it, if feasible, will help.If an infection is contributing to delirium, treating it will lead to improvement.

If withdrawal from alcohol, medication, or other substances is the problem, treating the withdrawal will be necessary.

Prescription antipsychotic medication such as haloperidol (Haldol) is often used to treat symptoms of delirium.

3 Sources

(Video) Audrey Curtis's Experience with Delirium

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. American Geriatrics Society Expert Panel on Postoperative Delirium in Older Adults. Postoperative delirium in older adults: best practice statement from the American Geriatrics Society. J Am Coll Surg. 2015;220(2):136-148.e1. doi:10.1016/j.jamcollsurg.2014.10.019

  2. Mattison MLP. Delirium. Ann Intern Med. 2020;173(7):ITC49-ITC64. doi:10.7326/AITC202010060

  3. Hayhurst CJ, Pandharipande PP, Hughes CG. Intensive care unit delirium. Anesthesiology. 2016;125(6):1229-1241. doi:10.1097/ALN.0000000000001378

By Jennifer Whitlock, RN, MSN, FN
Jennifer Whitlock, RN, MSN, FNP-C, is a board-certified family nurse practitioner. She has experience in primary care and hospital medicine.

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