Delirium Causes, Types, and Treatment Insights

Delirium is sudden mental confusion that develops quickly, usually within hours or days. The symptoms tend to come and go throughout a single day and require treatment to be cured, which can take days or weeks. If your loved one is battling waves of disorientation and fluctuations in awareness and perception, they might have delirium.

Delirium is not a chronic disease and is often reversible. There are many causes of the condition, and sometimes, a combination of causes needs to be treated simultaneously for effective outcomes. The majority of people who have delirium make a full recovery, provided the root causes are treated as soon as possible.

What is Delirium?

Delirium is a cognitive disorder that makes the sufferer feel confused, disoriented, and unable to think or remember things clearly. A person suffering from the condition might not know where they are or appear to be zoned out or lethargic. ^[1]

Depending on what type of delirium the person has, they could experience delusions or hallucinations. Mood swings between euphoria, anxiety, and fear might also take place. Delirium is not the same as dementia, although they have some similarities and may present the same. ^[1]

Delirium Versus Dementia

Delirium is commonly confused with dementia due to the two conditions having similar symptoms and sometimes co-occurring. However, there are a few key differences that tell them apart. ^[2]

While delirium has a sudden onset of fluctuating symptoms and is known to cause hallucinations, dementia comes on slowly and typically begins with memory loss. Delusions and hallucinations may develop in the later stages, but they do not occur in all cases of dementia. Delirium symptoms last from a few hours to a few months, and symptoms of dementia are chronic and progressive, meaning they get worse over time. ^[2]

Types of Delirium

There are three different types of delirium as follows:

Hypoactive

Hypoactive delirium is the most common form of delirium. Symptoms of hypoactive delirium manifest as extreme drowsiness or a “zoned out” state, where the person doesn’t respond much to others. This can be hard to spot, because they may just seem tired after being sick or having surgery. The good news is that 30 – 40% of hypoactive delirium cases can be prevented by diligent screening efforts and 1:1 patient engagement. ^[1]

Hyperactive

Hyperactive delirium appears as agitation and restlessness. People with this type may pace, wander, see, or hear things that aren’t there, have mood swings, or refuse treatment due to false beliefs (delusions), such as being in danger. It’s easier to notice than the calmer type of delirium, but it only makes up about 25% of cases. ^[1]

Mixed

Mixed delirium is a combination of hypoactive delirium and hyperactive delirium. This could look like being “out of it” one minute and pacing the next. A person with mixed delirium could be fatigued at times and then restless and agitated at others. These symptoms can continuously change throughout the day, which may make it seem like multiple health concerns are at play. ^[2]

Symptoms of Delirium

Delirium symptoms often appear suddenly, within a few hours or days, and may fluctuate throughout the day. Even with treatment, some symptoms can last for weeks or months, improving slowly. In some cases, delirium can lead to long-term brain changes, similar to dementia. Here are the most common symptoms of delirium: ^[2][3]

• Fluctuations in alertness: The person might seem more awake and alert in the morning but become very drowsy or “out of it” by evening. They may hold a clear conversation at breakfast but seem confused by dinner. As we mentioned earlier, there are a lot of similarities between the presentation of delirium and dementia, so this may be confused for sundowning – a term describing behaviors seen in late-stage dementia. ^[2]
• Shifting levels of consciousness: They may seem fine one moment and then suddenly become unresponsive or difficult to wake. For example, they might drift off mid-sentence or seem unaware of their surroundings. ^[2]
• Confusion: A person with delirium may not know where they are, what day it is, or who the people around them are. They could call a nurse “Mom” or think they’re at home when they’re in the hospital. ^[2]
• Disorganized thinking or speech: Their thoughts may not flow logically, and their words may not make sense. For example, they could say, “The sky is talking to my shoes,” or jump from one topic to another unrelated one. ^[2]
• Disrupted sleep patterns or excessive sleepiness: They may sleep all day, stay awake all night, or seem constantly tired. Sleep disturbances can contribute to confusion, leading someone to fall asleep during meals or wake up at odd hours, thinking it’s time for breakfast. ^[2]
• Emotional changes: A person with delirium could become unusually angry, sad, or euphoric for no apparent reason. For instance, they could suddenly yell at a caregiver or laugh loudly at something that isn’t funny. ^[2]
• Hallucinations and delusions: They might see or hear things that aren’t there or believe things that aren’t true. Examples of this could be insisting they see bugs on the wall (visual hallucinations), feeling itchy with no known cause (tactile hallucinations), or believing someone is trying to harm them (paranoid delusions). ^[2]
• Memory problems, especially short-term memory: Someone with delirium may forget recent events or conversations but remember older ones clearly. For instance, they might recall childhood stories but not what they ate for lunch that day. ^[2]
• Difficulty concentrating: They could struggle to focus or follow a conversation. This could look like losing track of what someone is saying after just a few words. ^[2]

Risk Factors for Delirium

Delirium commonly affects the elderly (those over 65) but can impact people of all ages. 80% of patients in the ICU and approximately a third of all hospital patients experience delirium. This is thought to be due to changes in brain signals when a person is very ill. Delirium is often a sign of a serious emerging health issue that can exist alongside it. ^[1][3][4]

People who have been hospitalized and developed delirium are more likely to face serious problems during their stay. This includes a higher risk of death. Around 35% to 40% of people who experience delirium in the hospital pass away within a year, but this is usually due to other severe health issues linked to delirium. ^[3]

Other delirium risk factors include having medical conditions like dementia and a history of conditions like strokes, neurological disorders or falls. People with multiple health concerns, chronic kidney or liver problems, and males are also at higher risk. ^[4]

Common Causes of Delirium

Delirium can be caused by one or several factors. Simply treating one cause might not be enough, so addressing all causes promptly is crucial. Below is the “delirium” acronym that is used to identify possible causes:

Drugs

One of the most common causes of delirium is prescription medicine, alcohol and recreational drugs. These substances can cause delirium as a side effect or due to intoxication. Drugs are the most common cause of delirium in younger people. Anesthetics and painkillers used during and after surgery can also cause delirium across ages. ^[2][3]

Electrolyte Disturbances

Imbalanced electrolytes like calcium, sodium, or magnesium can affect metabolic activity (how nerve cells work), causing delirium. These electrolyte imbalances might happen due to diuretics, dehydration, severe constipation, kidney failure, or advanced widespread cancer. ^[2][3]

Lack of Drugs

Delirium can also occur due to a lack of drugs, such as withdrawal from alcohol or other substances, including severe cases like delirium tremens. This often happens when people undergoing surgery cannot use substances they are dependent on. Insufficient pain management can also trigger delirium. ^[2][3]

Infection

Infections can cause delirium by triggering inflammation in the brain or interfering with normal body functions. This is especially common with urinary tract infections, pneumonia, and the flu, especially in older adults. Even minor illnesses (such as the flu) can sometimes lead to delirium, particularly in individuals already vulnerable due to age or other health conditions. ^[2]

Reduced Sensory Input

Sensory deprivation, such as being socially isolated or not having essential aids like glasses or hearing devices, can trigger delirium. In intensive care units, patients are often isolated in rooms without windows or clocks, which limits their connection to the outside world. The absence of typical sensory input can cause disorientation and increase the risk of delirium. ^[3]

Intracranial Problems

Delirium can be caused by conditions directly affecting the brain, including dementia, strokes, brain injuries and Parkinson’s disease. Brain infections like meningitis or encephalitis can also trigger delirium. Additionally, conditions like brain tumors or abscesses can damage the brain and lead to symptoms of delirium. ^[2][3]

Urinary Problems

Urinary problems can lead to delirium, especially when a bladder catheter is used. A catheter can increase the risk of urinary tract infections, a common cause of delirium. Additionally, issues like urinary retention or difficulty urinating can disrupt normal body balance, leading to mental changes and increasing the risk of delirium. ^[3][5]

Myocardial Issues

Myocardial issues, such as heart problems, can lead to delirium by reducing blood flow and oxygen to the brain. Organ failure, such as kidney or liver failure, can cause toxins to build up in the body, affecting brain function. When the brain doesn’t get the nutrients and oxygen it needs, it can lead to confusion, disorientation, and other symptoms of delirium. ^[2]

Treatment of Reversible Causes of Delirium

Prompt medical attention is necessary to treat the underlying reversible causes of delirium, and if addressed quickly, it can be cured and brain damage prevented. Delirium caused by drugs (whether through intoxication or side effects) can improve once the substances are removed or replaced with safer alternatives. ^[3]

Electrolyte imbalances can be corrected with medications, drips, or supplements. Withdrawal from substances or insufficient pain management can be managed by a doctor prescribing medication. Infections can be treated with antibiotics, leading to improvement in delirium symptoms. ^[2][3]

Restoring sensory input, such as access to glasses and hearing aids, can help reduce disorientation. A patient’s room should be well-lit so the person with delirium can easily recognize who and what is around them and their location. It’s a good idea to place calendars and clocks within sight. Family visits can also help. ^[2][3]

Having the same staff members treat the person with delirium is less disorienting. Urinary problems causing delirium can be resolved by managing retention issues and restoring normal brain function. While most causes of delirium are reversible, not all of them are. ^[2][3]

Prevention of Delirium

Most people with delirium are treated in the hospital, but if the cause can be easily fixed, they might only need a short stay in the emergency department. Once doctors figure out what’s causing the delirium, they quickly work to fix or treat it and make the environment as calm and quiet as possible to prevent agitation. ^[2]

It is helpful to explain any procedures beforehand and talk a person with delirium through them as they happen. People with the condition are at risk of problems like dehydration, poor nutrition, and falls, so they must receive thorough care, often from a team including doctors, nurses, and other specialists. ^[2]

If someone with delirium is very agitated or sees things that are not there, steps like having family or an attendant stay with them, placing them near the nurses’ station, or adjusting their medications can prevent harm. Restraints are sometimes needed to keep the person safe, but these should only be used when necessary and applied by trained staff. ^[2]

Key Takeaways

Delirium manifests in three different types: hypoactive, hyperactive and mixed. While hypoactive delirium presents as lethargy and confusion, hyperactive delirium is more restless and agitated and can involve delusions or hallucinations.

The main risk factor for delirium is being over the age of 65, especially for those in a hospital or the ICU. There are many delirium causes, but fortunately, most can be treated successfully and the delirium reversed. The condition must be treated immediately to avoid brain damage.