Delirium, or acute confusion, is a sudden change in mental function. Minor problems with memory and understanding, such as forgetting a name or taking more time to figure out directions, are a normal part of aging for everyone. However, some older adults develop extreme problems with remembering, understanding, or thinking. For example, they can "get lost" walking to the bathroom, become confused by simple tasks, forget the names of loved ones, and have difficulty speaking logically. These problems can be very difficult for people to cope with, and they also strongly affect family, friends, and other caregivers.
The most common problems are dementia and delirium. These two conditions share several characteristics that sometimes make it difficult to tell them apart. In addition, dementia and delirium also commonly occur at the same time. (See also Dementia.)
Characteristics of Dementia and Delirium| Dementia | Delirium |
| Slow onset over months to years | Sudden onset over hours to days |
| Normal speech | Slurred speech |
| Conscious and attentive | In and out of consciousness, inattentive, easily distracted |
| Memory loss | Memory loss |
| Language difficulties | Language difficulties |
| Hallucinations possible | Hallucinations common |
| Listless or apathetic mood most common; agitation also possible | Can be anxious, fearful, suspicious, agitated, or can seem to care less and react less |
| Often no other signs of illness | Signs of medical illness (eg, fever, chills, pain on urinating, etc) or drug side effects common |
Delirium is one of the most common complications of medical illness or recovery from surgery among older adults in the hospital. Delirium has also been called acute confusional state, toxic psychosis, metabolic encephalopathy, or acute organic brain syndrome.
Delirium has been described in the medical literature for more than 2,000 years, and it is still quite common today. One-third of older adults arriving at hospital emergency departments are delirious. Similarly, approximately one-third of patients aged 70 or older admitted to the hospital for general medical care experience delirium. Delirium is even more common among older adults admitted to intensive care units. Delirium is present in half of hospital patients transferred to a nursing home.
Delirium is traditionally viewed as a short-term, temporary problem, but evidence is growing that it may persist for weeks to months in a substantial number of people. Very old people with pre-existing mental difficulties seem to be at highest risk of long-term delirium. In general, all types of delirium appear strongly associated with poor outcomes among hospitalized patients. These include increased chance of death, complications, long hospital stays, and nursing home care after discharge. Poor outcomes are particularly common among older adults who have long-term delirium.
Diagnosis
When people hear the term delirium, many think it means that someone is wildly agitated. However, the type, number, and severity of symptoms vary quite a bit. Only about one-quarter of people with delirium are agitated. Most people with delirium have "quiet" delirium, or delirium with a mix of symptoms (eg, agitated at times and quiet at times). The prognosis for quiet delirium is that same as that for agitated delirium, but it is recognized and treated less frequently.
A diagnosis of delirium is based on careful observation, awareness of changes in the person's usual mental state, and knowledge of the current physical problems. Usually, trying to talk to the person shows that his or her attention wanders and that he or she is distracted easily and has a hard time following directions. The person may speak in a disorganized way that does not make much sense. He or she may also appear restless and move a lot, and may "nod in and out." During the night, sometimes the muscles jerk and twitch and, rarely, the hands "flap."
The person's difficulty in thinking may not be obvious. Healthcare professionals sometimes use a series of simple standardized questions to try to evaluate mental function. Using standardized questions makes it possible to monitor future improvement or decline to some extent. Types of standardized questions include the following:
When a medical condition(s) that is causing delirium is not apparent, a complete history and physical examination are necessary. The history should include a review of all drugs being taken, including over-the-counter medications, herbal remedies, etc (see Health Assessment). The healthcare provider may also recommend diagnostic laboratory tests such as blood tests, a urinalysis, a brain imaging study (eg, a CAT scan or MRI), or an electroencephalogram (EEG). An EEG monitors brain waves through electrodes placed on the scalp. Although an EEG may not determine the reason for delirium, it is a good test for ruling out delirium. In other words, if the EEG is normal, the person does not have delirium.
Causes
We don't yet know all the mechanisms that can cause delirium, but some causes are known. A key goal of treatment is to identify any causes and correct those that are reversible. Reversible causes of delirium include the following:
Delirium can reflect changes in a chemical in the brain called acetylcholine, which transmits signals between nerves. Levels of acetylcholine can be affected in many ways. If oxygen or glucose levels in the brain go down, even by a small amount, the amount of acetylcholine can go down significantly. Brain damage in people with Alzheimer's disease can kill the cells in the brain that produce acetylcholine, making the brain more prone to delirium when supplies of oxygen or glucose become limited. Medications that block acetylcholine can also produce delirium. In fact, side effects of medication are the most common and most treatable cause of delirium.
Drugs
Many common drugs can trigger delirium in older adults. These include narcotics (and other pain relievers), sedatives, corticosteroids, and drugs that specifically affect acetylcholine levels in the brain (eg, atropine). Drugs are a leading cause of delirium in the hospital. In addition, nearly 60% of nursing-home residents and about 25% of older adults living in the community take drugs that block at least some acetylcholine transmission, which could lead to delirium.
Alcohol abuse is frequently overlooked as a cause of delirium in older adults. Delirium can be result from either intoxication or a sudden withdrawal from alcohol. Delirium caused by withdrawal of alcohol (ie, the "DTs") appears to be as common in older adults with alcoholism as in their younger counterparts. However, the death rate after withdrawal is higher in older alcoholics than in younger ones. Delirium can also be caused by withdrawal from sedatives that have been taken for a long time.
Medical conditions
Virtually any medical condition can potentially cause delirium. For example, delirium may be the first sign of a serious, life-threatening illness such as a heart attack. Often, a person has more than one potential medical cause. The most common causes among people in the hospital include problems in bodily fluids, drug reactions, infections, low blood pressure, and low levels of oxygen in the blood. Delirium caused by a sudden change in the nervous system, such as a stroke, brain tumor, or brain infection, is seem in only a small number of people.
Delirium can also result from too little stimulation of the senses, especially in people who already have some degree of mental impairment. In one study, delirium after an operation occurred twice as often in patients in intensive care units without windows as in patients in similar units with windows. In addition, a form of delirium that occurs at night (ie, sundowning) may be partly due to sensory deprivation. Vision and hearing loss may make it more difficult for the person to perceive reality and increase the chances of delusions or hallucinations.
Delirium after surgery
Delirium may be the most common complication after surgery in older adults. Delirium after surgery in older adults leads to longer hospital stays, a higher death rate, and a greater need for nursing-home care after discharge. Delirium may be the first sign of medical complications after surgery, such as infection, heart problems, or drug toxicities.
Several personal or medical risk factors seem to increase the chances of delirium after surgery. These include advanced age, pre-existing dementia, pre-existing physical disability, history of alcohol abuse, and very abnormal results of certain blood tests. The type of acute (eg, general, spinal, or epidural) does not seem to affect the risk of delirium, but the type of operation does. For example, delirium is much more common after hip surgery and chest surgery.
Differentiating Delirium from Look-Alike Conditions
Delirium can be mistaken for dementia or for psychiatric diseases such as schizophrenia. Certain rare forms of epilepsy can also closely resemble delirium. However, in epilepsy there is usually a history of seizures before the episode of sudden confusion.
The best way to differentiate delirium from psychiatric problems is by considering age and the rate of onset of symptoms. Any sudden change in an older person's behavior should be considered as possible delirium until examination or testing proves otherwise. Other features that may help separate psychiatric disease from delirium are the types of hallucinations that the person experiences. Psychotic patients typically hear voices or sounds, while people with delirium usually see things. In addition, physical characteristics that are typical of delirium (eg, hand flapping and EEG changes), or evidence of a sudden underlying medical illness, are generally absent in psychiatric disorders.
Dementia also produces memory and thinking problems, just like delirium. However, dementia has a much longer onset, and mental abilities vary much less over the course of hours or days. In addition, people with dementia generally remain aware of their environment until very late in the illness. It is important to remember that dementia and delirium can be seen together, and that delirium develops commonly in people with dementia. Whenever the behavior or thinking of a person with dementia deteriorates suddenly, particularly when the person is sick or hospitalized, the cause is likely to be delirium.
Treatment
The best way to treat delirium is first to prevent it, by careful attention to underlying causes and triggers (eg, medications). However, when delirium does occur, it is a true medical emergency that requires immediate evaluation and treatment. The cornerstones of medical management include promptly identifying the condition and the specific cause, managing any agitation or disruptive behavior, and providing general supportive care. Because delirium can be caused by so many different things, there is no simple strategy for evaluation.
The main goal of treatment is to identify and correct the underlying cause of delirium. Generally, a comprehensive medical evaluation is needed, including specific laboratory tests. These may include simple blood tests and more sophisticated tests like brain imaging studies (eg, CAT scan and MRI). Unless they are absolutely necessary, all drugs are generally stopped.
Supportive care for people with delirium includes careful attention to medical, environmental, and social situations. People with delirium are particularly vulnerable to complications and poor outcomes and must be given special hospital care. Medical complications include problems with bodily fluids, inhaling secretions or vomit, malnutrition, pressure ulcers, joint stiffness, and other conditions such as constipation or wetting oneself that might result from not being able to move around much or from reduced consciousness.
Management of the environment involves continually helping the person feel oriented, avoiding unnecessary moves from one room or space to another. Leaving on dim lights at night can help decrease delusions or hallucinations. Things like clocks, calendars, and window views can help with orientation. Eyeglasses or hearing aids can improve a person's link to reality. Family members, close friends, or even paid assistants to be with the person can reduce the fear and anxiety seen in delirium.
Professionals in social work and nursing are often quite skilled at helping people with delirium. A person's hospital behavior while he or she is in the hospital may not accurately predict how well he or she will do at home in a familiar, stable environment. This should be kept in mind so that the decision to place someone in a nursing home is not made prematurely.
Drug treatment is often not necessary, or desirable, in cases of delirium. However, sometimes, drug treatment is needed to control highly agitated or disruptive behaviors that could cause injury. Most often, antipsychotic drugs are used, but cautiously. Sedatives can actually trigger delirium, so they are used for only a short time and only in cases of serious agitation. Sedatives are never used in people who are already drowsy or who cannot be easily wakened.
Physical restraints should rarely, if ever, be used in delirium. There is no evidence that they reduce falls or other accidents. In addition, they prevent movement, which increases the risk of developing pneumonia or pressure ulcers. Accidental strangling is even a possibility. Also, restraints and very strong medications are considered a form of involuntary treatment and may violate the rights of an agitated person.
Outlook
Family members need to understand that delirium is usually not a permanent condition, and that it improves over time, although it may take weeks or months. Slow recovery is more common if delirium is severe or if the person already has dementia or is 85 years old or older. Careful supportive care and monitoring of mental status during this period are crucial to recovery.
Family members can play an important role by providing appropriate orientation, support, and assistance. More and more, hospitals are allowing family members to sleep overnight with relatives who are already delirious or at high risk of becoming delirious. Families should seek prompt medical attention if the patient's mental status worsens suddenly.