Delirium is a mental state in which you are confused, disoriented, and not able to think or remember clearly. It usually starts suddenly. It is often temporary and treatable.

There are three types of delirium:

• Hypoactive, where you are not active and seem sleepy, tired, or depressed
• Hyperactive, where you are restless or agitated
• Mixed, where you change back and forth between being hypoactive and hyperactive

There are many different problems that can cause delirium. Some of the more common causes include

• Alcohol or drugs, either from intoxication or withdrawal. This includes a serious type of alcohol withdrawal syndrome called delirium tremens. It usually happens to people who stop drinking after years of alcohol abuse.
• Dehydration and electrolyte imbalances
• Dementia
• Hospitalization, especially in intensive care
• Infections, such as urinary tract infections, pneumonia, and the flu
• Medicines. This could be a side effect of a medicine, such as sedatives or opioids. Or it could be withdrawal after stopping a medicine.
• Metabolic disorders
• Organ failure, such as kidney or liver failure
• Poisoning
• Serious illnesses
• Severe pain
• Sleep deprivation
• Surgeries, including reactions to anesthesia

Certain factors put you at risk for delirium, including

• Being in a hospital or nursing home
• Dementia
• Having a serious illness or more than one illness
• Having an infection
• Older age
• Surgery
• Taking medicines that affect the mind or behavior
• Taking high doses of pain medicines, such as opioids

The symptoms of delirium usually start suddenly, over a few hours or a few days. They often come and go. The most common symptoms include

• Changes in alertness (usually more alert in the morning, less at night)
• Changing levels of consciousness
• Confusion
• Disorganized thinking, talking in a way that doesn't make sense
• Disrupted sleep patterns, sleepiness
• Emotional changes: anger, agitation, depression, irritability, overexcitement
• Hallucinations and delusions
• Incontinence
• Memory problems, especially with short-term memory
• Trouble concentrating

To make a diagnosis, the health care provider

• Will take a medical history
• Will do physical and neurological exams
• Will do mental status testing
• May do lab tests
• May do diagnostic imaging tests

Treatment of delirium focuses on the causes and symptoms of delirium. The first step is to identify the cause. Often, treating the cause will lead to a full recovery. The recovery may take some time - weeks or sometimes even months. In the meantime, there may be treatments to manage the symptoms, such as

• Controlling the environment, which includes making sure that the room is quiet and well-lit, having clocks or calendars in view, and having family members around
• Medicines, including those that control aggression or agitation and pain relievers if there is pain
• If needed, making sure that the person has a hearing aid, glasses, or other devices for communication

Treating the conditions that can cause delirium may reduce the risk of getting it. Hospitals can help lower the risk of delirium by avoiding sedatives and making sure that the room is kept quiet, calm, and well-lit. It can also help to have family members around and to have the same staff members treat the person.

Ill and hospitalized older people sometimes experience episodes of delirium, a state of confusion and disorientation. For centuries considered a transient and reversible condition, delirium in older people is still viewed by many to be a normal consequence of surgery, chronic disease, or infections.

There is mounting evidence, however, that delirium may be associated with increased risk for dementia and may contribute to morbidity and death. One recent study found that in a group of 553 people age 85 and older, those with a history of delirium had an eight-fold increase in risk for developing dementia (Davis et al., 2012). The researchers also found that among the participants with dementia, delirium was associated with an acceleration of dementia severity, loss of independent functioning, and higher mortality. These findings showed that delirium is a strong risk factor for dementia and cognitive decline in the oldest old.

Growing momentum, awareness

At NIA and throughout the geriatric research community, momentum is building to better understand the mechanisms involved in delirium and to improve ways to recognize and treat the condition.

Currently, NIA supports several clinical trials focused on finding effective drugs and protocols to prevent or reduce the impact of delirium in hospitalized older people. The goal is to identify a variety of interventions that reduce delirium for patients in intensive care, including the testing of supplements, pain medications, and sedatives that may alleviate delirium in pre- and post-operative patients.

“The research and medical communities are becoming more aware and interested in the impact delirium may have on the long-term cognitive health of older patients,” said Dr. Molly Wagster, Chief of NIA’s Behavioral and Systems Neuroscience Branch.

“At this stage, unfortunately, there are more questions than answers. In order to treat or prevent delirium, it will be important to determine why some older people are more susceptible to developing it during hospital stays or as a result of trauma or illness.”

In addition to supporting the clinical trials, NIA, in collaboration with the American Geriatrics Society (AGS), is sponsoring a conference on delirium in early 2014 through a cooperative grant mechanism. As part of the AGS Bedside-to-Bench conference series, the meeting will cover a wide array of delirium-related research topics, including biomarkers, genetic risk factors, neuroimaging, inflammation, brain injuries, drug and nondrug interventions, and animal models. Recommendations from the meeting will inform research on this topic for years to come.

These activities join efforts already underway of the American Delirium Society (ADS), a group formed by researchers and clinicians seeking better understanding of the science of delirium and its prevention, treatment, and long-term consequences. The group hosts an annual conference that draws a mix of clinicians and scientists from many different disciplines and specialties.

Attitudes about delirium evolving

Dr. Joseph Flaherty of the Division of Geriatrics at Saint Louis University, a leading member of ADS, says that attitudes about delirium are slowly evolving among medical practitioners.

“As a medical student 20 years ago, I was taught delirium was completely reversible. That’s simply not the case for many older patients,” he said. “Over the past 15 years, interest has grown in identifying ways not only to reverse the condition, but to prevent it from occurring in the first place.”

He applauds NIA funding of delirium drug trials, but also suggests that changes in nursing and hospital protocols today could help prevent the onset or reduce the severity of delirium.

“Changing the hospital environment and culture to match what the older patient with delirium or at risk for delirium needs is critical,” Dr. Flaherty said.

Examples of such changes include allowing hospitalized older people to sleep undisturbed between 10 p.m. and 6 a.m. so that their normal sleep cycle is less disrupted, not using physical restraints, and giving staff concrete nonpharmacologic methods to deal with agitation that may occur with delirium (Flaherty et al., 2011).

“There are very promising, nonpharmacological methods being tested that may enable hospitals and nursing facilities to prevent, treat, and manage delirium,” he said. “For example, the new standard in ICUs is to get patients up and out of their beds within 1 to 2 days, even if they are connected to a ventilator. This reduces the number of days with delirium and time spent in intensive care.”

Dr. Flaherty said these new methods may also improve the odds of regaining normal cognitive as well as physical function (Schweickert et al., 2009).