Delirium - Types | Cause | Symptoms | Diagnosis | Treatment
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Delirium - Types, Cause, Symptoms, Diagnosis and Treatment

Written by 
Dr. Anuthanyaa. R
 and medically  reviewed by Dr. Parth Nagda

Education: MBBS, MD Psychiatry

Professional Bio: Dr. Parth N. Nagda is a Psychiatrist based in Navi Mumbai, Maharashtra. He has 3.5 years of clinical experience and is currently a consultant at Kokilaben Dhirubhai Ambani Hospital, Navi Mumbai. He is... 

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Published on Apr 12, 2022 and last reviewed on Mar 10, 2023   -  5 min read


Delirium is a serious change in mental abilities resulting in mental confusion, emotional disruption, etc. To know more, read the article below.

What Is Delirium?

Delirium is also called an acute confusional state, in which a person becomes confused, and disoriented over a short period, usually within hours to days. Typically it starts suddenly, and this sudden change in mental status could be reversed. All of these result in difficulty in paying attention, thinking, sleeping, and remembering things.

A person may experience delirium during severe or chronic illness, infection, alcohol withdrawal, certain medications, changes in metabolic balance, surgery, drug intoxication, or when there is dementia. Delirium is not permanent and can be treated effectively. In addition, delirium and dementia symptoms can be similar, so it might be difficult for the doctor to come to an accurate diagnosis. Initially, delirium occurs within hours or within a few days.

What Are the Types of Delirium?

The delirium types are categorized based on the cause, severity, and other characteristics. They are:

  1. Delirium Tremens - This is experienced in people who try to stop drinking and have been drinking alcohol constantly for so many years.

  2. Hyperactive Delirium - People will be highly uncooperative and alert.

  3. Hypoactive Delirium - This delirium type is more common. People with this delirium will not be attentive, sleep more, and will not be organized in their daily tasks. Also, they may miss their important appointments and daily meals.

  4. Mixed Delirium - People with this type have a combination of hyperactive and hypoactive delirium, alternating between the two states.

What Are the Causes of Delirium?

When the brain's regular to and fro signals are impaired, delirium occurs. The brain function is interfered with or impaired due to a lot of factors that combine to make it vulnerable and trigger the malfunctioning of the brain's activity. Those factors are listed below, and as already explained, delirium may have one or more causes, like a combination of drug toxicity with a medical condition.

  1. Fever and acute infection, especially in children.

  2. Pneumonia, urinary tract infection, or the flu, particularly in older adults.

  3. Drug toxicity and certain medications.

  4. Dehydration and malnutrition.

  5. Changes in metabolic balance (low calcium or low sodium).

  6. Alcohol withdrawal or drug intoxication.

  7. Pain.

  8. Severe or chronic illness.

  9. Certain medical conditions such as a heart attack, severe lung disease, liver damage or disease, stroke, injury due to a fall or trauma.

  10. Sleep disturbances or severe emotional deprivation.

  11. Surgical procedures or other medical procedures that incorporate anesthesia.

  12. Exposure to toxins such as cyanide, carbon monoxide, or some other poisons.

  13. There are several drugs or combinations of medications that can trigger delirium. Some of those drug groups are:

  • Analgesics (painkillers).

  • Sleeping medications.

  • Drugs used for mood disorders, such as depression and anxiety.

  • Allergy medications (antihistamines).

  • Asthma medications.

  • Steroid medicines known as corticosteroids.

  • Parkinson's disease drugs.

  • Drugs for treating spasms or convulsions.

What Are the Symptoms of Delirium?

Generally, the symptoms of delirium start over a few hours to days, and they most often fluctuate throughout the day. Occasionally there are periods of no symptoms, and when they occur, they tend to become worse at night (when it is dark and while looking at objects, it may seem less familiar to affected individuals). The symptoms of delirium are as follows;

Changes in Behavior and Thinking Skills:

  1. Unable to focus on a particular topic.

  2. Unable to switch to other topics.

  3. Do not respond to the questions asked or to a conversation.

  4. Being stuck with a single idea.

  5. Not able to respond to the environment.

  6. Not able to recognize the recent events.

  7. Not even able to recognize where they are or who they are.

  8. Imagining or seeing things that do not exist. (Medically called hallucinations).

Changes in Speech and Learning Skills:

  1. Restlessness.

  2. Being quiet, particularly in older adults.

  3. Difficulty in reading, speaking, recalling words, and writing.

  4. Trouble understanding speech.

  5. Rambling speech.

  6. Difficulty in speaking.

  7. Poor memory.

Sleep Changes:

  1. Sleep disturbances.

  2. Change in the sleep cycle.

Emotional Changes:

  1. Anxiety.

  2. Slow movements.

  3. Depression.

  4. Fear.

  5. Irritability and anger.

  6. Unpredictable mood swings.

  7. Feeling of intense happiness.

  8. Lack of interest in anything.

How Is Delirium Diagnosed?

Based on the symptoms experienced, the doctor will make use of a technique called a confusion assessment method to check if the person can speak, think and move normally. The doctors will continuously observe the person for the severity of the symptoms.

By using the confusion assessment method, it is possible to identify whether:

  1. The person's behavior changes between days, or within a day, mainly during hospitalization.

  2. A person is rambling.

  3. There is trouble thinking straight or having proper attention while listening to others.

  4. The person is able to move around without any problems.

  5. There is a good memory power or can identify others.

Since the change in the chemical equilibrium of the brain is affected by many factors, it is important for the doctor to identify the exact cause behind delirium by making use of the required tests based on the patient's medical history and the symptoms. Some of the commonly used tests to check for chemical imbalance are:

  1. Thyroid test.

  2. Blood chemistry test.

  3. Head scans - brain imaging.

  4. Urine tests.

  5. Drug and alcohol test.

  6. Chest X-ray.

  7. Liver test.

There are certain neurological tests that can be done in order to check for any underlying health conditions. During these tests, vision, reflex, coordination, and balance will be checked to determine whether any neurological disease is responsible for delirium.

How Is Delirium Treated?

The first and foremost step in treating delirium is to identify any triggers or underlying health conditions that are responsible for the condition itself. These include withdrawal from certain medicines, metabolic imbalance, and any other infection. Then the treatment will focus on keeping the brain in healing and a calm environment. This can be done by certain supportive care, which includes:

  1. Taking care of the airways.

  2. Consuming proper nutrition and fluids.

  3. Taking care of pain and infections.

  4. Getting help for movements.

  5. Avoiding major changes to the environment.

  6. If there is any incontinence, then address it immediately.

  7. Involving with others such as family members and friends.

Apart from these, medications can also help in managing delirium. It is important for the family members to discuss with the doctors to check if there is any medicine that is causing the condition. The medicines will mainly be given for calming the persons who are easily agitated by changes in the environment or hallucinate or fear the presence of other people.


If you are a caretaker, or if you are a family member of someone who is suffering from delirium, it is possible for you to help them by taking small steps for improving the person’s health and preventing it from recurring again. Make sure there is no major change in their surroundings and provide encouragement for their activities. Ensure a quiet environment and help them have a regular schedule in order to boost the healing of the brain.

Last reviewed at:
10 Mar 2023  -  5 min read

Dr. Parth Nagda

Dr. Parth Nagda



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