Overview
Delirium is a serious change in mental abilities. It causes people to become confused and unaware of their surroundings. This condition comes on fast. Typically, symptoms appear over a few hours or a few days.
A number of medical concerns may cause delirium, including having a serious or long illness. Delirium might be due to not having enough of an important nutrient in the body, such as having low sodium levels. Delirium also may be caused by some medicines, infection, surgery, or substance use or withdrawal, including alcohol and other drugs.
Symptoms of delirium can look like symptoms of dementia. To diagnose delirium, healthcare professionals may rely on input from family members, caregivers or other people familiar with the person's typical abilities.
Symptoms
Symptoms of delirium usually begin over a few hours or a few days. They typically happen along with another medical condition or in addition to other symptoms, such as pain or fever. Delirium symptoms often come and go. There may be times when symptoms disappear. Symptoms tend to be worse in dark or unfamiliar settings, such as at night or in a hospital room.
The main symptoms of delirium fall into several broad categories.
Less awareness of surroundings
This may lead to:
- Trouble focusing on a conversation topic or a following a change in topics.
- Getting stuck on an idea rather than responding to questions.
- Being easily distracted.
- Being withdrawn, with little or no activity or little response to surroundings.
Poor thinking skills
This may appear as:
- Poor memory, such as forgetting recent events.
- Not knowing where they are or who they are.
- Trouble with speech or remembering words.
- Rambling speech or speech that's hard to understand.
- Trouble understanding what others are saying.
- Trouble reading or writing.
Behavior and emotional changes
These may include:
- Anxiety, fear or distrust of others.
- Depression.
- A short temper or anger.
- A sense of feeling very happy or elated.
- Lack of interest and emotion.
- Quick changes in mood.
- Personality changes.
- Seeing things that others don't see.
- Being restless or anxious.
- Being quick to argue.
- Calling out, moaning or making other sounds.
- Being quiet and withdrawn.
- Slowed movement or being sluggish.
- Changes in sleep habits.
- Being awake at night and sleeping during the day.
Types of delirium
There are three types of delirium:
- Hyperactive delirium. This may be the easiest type of delirium to recognize. People with this type may be restless and pace the room. They also may be anxious, have quick mood swings or see things that aren't there. They may cry out or become agitated. People with hyperactive delirium may resist medical care or be unable to cooperate with medical care due to the change in their mental state.
- Hypoactive delirium. People with this type of delirium may have a low level of activity. They tend to be sluggish or drowsy. They might seem to be in a daze. They tend not to interact with other people.
- Mixed delirium. Symptoms of mixed delirium include symptoms of both of the other types of delirium. People with mixed delirium may quickly switch back and forth from being restless and anxious to being sluggish and drowsy.
Delirium and dementia
Delirium and dementia may be hard to tell apart. Some people may have both. Someone with dementia has a slow decline of memory and other thinking skills. This is due to damage or loss of brain cells. The most common cause of dementia is Alzheimer's disease, which comes on slowly over months or years.
Delirium often happens in people with dementia. But having an episode of delirium doesn't always mean a person has dementia. Tests for and a diagnosis of dementia shouldn't be made during a delirium episode because test results may not be accurate.
Some differences between the symptoms of delirium and dementia include:
- How quickly symptoms start. Symptoms of delirium appear quickly, typically over a day or two. Dementia begins with minor symptoms that get worse over time.
- Attention. It's hard for people with delirium to stay focused. In contrast, people in the early stages of dementia generally stay alert. Someone with dementia often isn't sluggish or agitated.
- Rapid changes in symptoms. Delirium symptoms can come and go several times during a day. While people with dementia have better and worse times of day, their memory and thinking skills typically stay at a constant level.
When to see a doctor
If a family member, friend or someone you support shows symptoms of delirium, talk to that person's healthcare professional as soon as possible, especially if there are symptoms of an infection, such as a cough or urinary concerns. Your input about a person's symptoms, typical thinking and other abilities will be important for a diagnosis. Telling the team about changes you've seen also can help find the cause of delirium.
If you notice symptoms of delirium in someone in the hospital or in a long-term care center, tell the nursing staff or another member of the healthcare team right away. Older adults who are in the hospital, especially those in intensive care, and people living in a long-term care center are at higher risk of delirium.
Causes
Delirium happens when signals in the brain aren't sent and received correctly.
Delirium may have a single cause or more than one cause. For example, a medical condition along with the side effects of a medicine could cause delirium. Sometimes no cause can be found.
Possible causes of delirium include:
- Urinary tract infection, pneumonia, the flu or COVID-19, especially in older adults.
- Certain medicines or medicine side effects.
- Alcohol or drug use or withdrawal.
- A medical condition such as a stroke, heart attack, lung or liver disease that's getting worse, or an injury from a fall.
- Not enough of an important nutrient in the body, such as low sodium or low calcium levels.
- Serious, long-lasting illness or an illness that is expected to lead to death, also called terminal illness.
- Fever and a new infection, particularly in children.
- Exposure to a toxin, such as carbon monoxide or other poisons.
- Poor nutrition or a loss of too much body fluid.
- Lack of sleep.
- Intense emotional stress.
- Pain.
- Surgery or another medical procedure that requires being put in a sleeplike state.
Some medicines taken alone or taken together can trigger delirium. These include medicines that treat:
- Pain.
- Sleep disorders.
- Mood disorders, such as anxiety and depression.
- Allergies.
- Asthma.
- Swelling.
- Parkinson's disease.
- Spasms or convulsions.
Risk factors
Any condition that leads to a hospital stay raises the risk of delirium. This is especially true when someone is recovering from surgery or is in intensive care. Delirium is more common in older adults who are in the hospital and in people who live in long-term care centers.
Examples of other conditions that may raise the risk of delirium include:
- Brain disorders such as dementia, stroke or Parkinson's disease.
- Past delirium episodes.
- Vision or hearing loss.
- Substance use or withdrawal, including alcohol and other drugs.
- Having multiple medical conditions.
Complications
Delirium may lead to other health concerns, called complications. The complications people with delirium develop tend to depend on how quickly they recover from delirium. The condition may last only a few hours, or it may last several days, weeks or months. If the causes of delirium are successfully treated, recovery time often is shorter.
Recovery depends in part on how healthy a person was before delirium started. For example, people with dementia may have an overall decline in memory and thinking skills after a delirium episode. People in better health are more likely to fully recover.
People with other serious, long-lasting or terminal illnesses may not get back the thinking skills and other mental skills that they had before an episode of delirium. Delirium in seriously ill people is more likely to lead to:
- A general decline in health.
- Poor recovery from surgery.
- The need for long-term care.
- A higher risk of death.
Prevention
Some steps can help prevent delirium or make it less serious if it happens. Those steps include:
- Getting good sleep.
- Staying calm and aware of surroundings.
- Preventing or quickly treating medical concerns.
- Avoiding medicines used for sleep, such as diphenhydramine (Benadryl Allergy, Unisom, others).
Taking these steps may be hard when someone is in the hospital. That's because hospital stays often include room changes, invasive procedures, loud noises and poor lighting. And lack of natural light and lack of sleep can make confusion worse. If you're worried that someone in the hospital may be at risk of delirium, talk to a member of the healthcare team.