Delirium is a sudden change in a person's mental function, which includes their ways of thinking and their behavior or level of consciousness. This change often affects memory and concentration.

Medical professionals do not yet fully understand delirium, but it seems to have an association with older age, alcohol withdrawal, and certain medical conditions.

In this article, we discuss different types of delirium and their associated symptoms. We also talk about delirium's possible causes and risk factors. Finally, we cover diagnosis, treatment options, and when to see a doctor.

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A person experiencing delirium may find it difficult to concentrate, think, remember, and sleep.

Delirium results in a sudden change in a person's mental function, which can disrupt their ability to concentrate, think, remember, and sleep. It can also cause fluctuations in their level of consciousness.

Delirium can occur as a result of aging, alcohol withdrawal, certain medications, and underlying medical conditions.

According to the authors of a 2013 article, there is a link between delirium and adverse health outcomes, such as extended hospital stays, faster cognitive decline, and a higher likelihood of developing dementia.

Delirium remains a poorly understood and potentially underdiagnosed condition.

Doctors diagnose people with one of three types of delirium, which have different symptoms. The three types are:

  • hypoactive delirium: people may feel tired or depressed or move slower than normal
  • hyperactive delirium: people may feel restless, agitated, or aggressive
  • mixed delirium: people alternate between hypoactive and hyperactive states

Some people who have delirium do not experience any physical symptoms. Doctors will refer to this form of delirium as delirium without motor symptoms.

All types of delirium can include the following symptoms:

  • confusion or disorientation
  • memory loss
  • slurred speech or difficulty speaking coherently
  • difficulty concentrating
  • hallucinations
  • changes in sleep patterns
  • changes in mood or personality

Medical professionals do not know the exact cause of delirium. However, inflammation of the brain, imbalances in neurotransmitters, and chronic stress may all play a role in the onset of symptoms.

Causes of delirium can include:

  • infections, such as pneumonia and urinary tract infections
  • imbalances in acetylcholine or dopamine levels
  • brain tumors
  • head trauma
  • kidney or liver failure
  • alcohol, medicine, or drug misuse
  • certain medications, such as blood pressure medications, sleeping pills, and sedatives
  • exposure to toxic substances
  • extreme sleep deprivation

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Surgery may increase people's risk of delirium.

People over the age of 70 years have a higher risk of delirium.

Other factors that can increase a person's risk of delirium include:

  • having surgery
  • experiencing intense pain
  • having a history of conditions that injure the brain, such as stroke and dementia
  • having anemia
  • being male
  • having a functional disability
  • having poor vision and hearing
  • having mild cognitive impairment
  • overusing alcohol
  • taking legal or illegal psychoactive drugs, such as opioids, antidepressants, or hypnotic sleep aids

Healthcare professionals pay attention to both the physical and psychological symptoms when diagnosing delirium.

They can use a combination of cognitive health assessments, physical exams, and laboratory tests to help them diagnose delirium and identify the underlying cause.

Confusion assessment method

Healthcare professionals can use the Confusion Assessment Method (CAM) to help them diagnose delirium. They will look for the following indications of delirium during a CAM assessment:

  • Acute onset: Does the person show a sudden change in their mental status?
  • Inattention: How well can they focus on what other people say to them? Do they experience changes in their ability to focus?
  • Disorganized thinking: Does their thinking follow a logical or illogical flow? People who have disordered thinking tend to ramble, switch between subjects at random, or make irrelevant statements during a conversation.
  • Altered level of consciousness: Do they display signs of being alert, hyperalert, lethargic, or comatose?
  • Disorientation: Do they show signs of disorientation or confusion during the assessment?
  • Memory impairment: Do they have difficulty remembering recent events or instructions?
  • Perceptual disturbances: Do they see, hear, or feel things that are not there?
  • Psychomotor agitation: Are there signs of restlessness, such as fidgeting, finger tapping, or suddenly changing positions?
  • Psychomotor retardation: Are they staring into space, staying in one position for a long time, or moving slowly?
  • Altered sleep-wake cycle: Does the person report insomnia and extreme daytime fatigue?

Physical tests

Along with the CAM assessment, healthcare professionals may use other tests to identify the underlying cause of delirium.

The following tests can help them check for imbalances in a person's brain chemistry or electrolyte levels and confirm the presence of any other medical conditions:

  • blood tests
  • urine tests
  • drug and alcohol tests
  • electrocardiography
  • chest X-ray
  • CT scan
  • liver function test
  • lumbar puncture
  • thyroid test

Delirium can cause symptoms that also appear in other medical conditions, such as dementia and psychosis. Healthcare professionals have to rule out these other conditions before they can diagnose and treat delirium.

Dementia

Similar to delirium, dementia commonly affects older adults. According to the National Institute on Aging, approximately 50% of people aged 85 years or older may have some form of dementia.

Dementia has numerous possible causes, which can include:

Unlike delirium, which usually resolves once doctors treat the underlying condition, no cure exists for dementia. Additionally, dementia typically develops over several years, whereas delirium has an acute onset, appearing within days or even hours.

Psychosis

Psychosis is a symptom of several health conditions. It disrupts the person's thoughts and perceptions, making it difficult for them to identify with reality.

Psychosis is relatively common. According to the National Alliance on Mental Illness, as many as 3 in every 100 people will have an episode of psychosis during their lifetime.

Causes of psychosis include:

People may experience the following symptoms during a psychotic break:

  • general anxiety or depression
  • paranoia
  • obsessive thoughts
  • changes in sleep patterns
  • sudden changes in mood or personality
  • hallucinations or delusions
  • difficulty concentrating or focusing on a single subject
  • disorganized thinking, speech, or behavior
  • unresponsiveness

Unlike delirium, doctors use medication as the first-line treatment for psychosis.

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A doctor may prescribe medication to treat the underlying cause of delirium.

The Food and Drug Administration (FDA) have not approved any medications for the treatment of delirium itself. The first-line treatment for delirium usually focuses on identifying and treating the underlying cause.

If the delirium is due to a change in medication, stopping the offending medication may be all that is necessary.

Doctors can prescribe medications to treat the underlying cause of delirium. For example, if someone has an untreated bacterial infection, a doctor is likely to prescribe a course of antibiotics.

Doctors may prescribe low dosages of psychotropic medications to people who have severe or dangerous symptoms, such as extreme agitation or demonstrating violent behaviors. Examples of psychotropic medications that a doctor might prescribe include:

  • antidepressants
  • sedatives
  • dopamine blockers

According to the authors of a 2018 review article, people may continue experiencing symptoms of delirium for several days to months after doctors start treating the underlying cause.

People should contact a doctor or another healthcare professional if they or a loved one has a rapid change in mental state or shows any of the symptoms of delirium that we mention in this article.

Delirium refers to a sudden change in mental status, which can result in confusion, memory issues, or changes in a person's emotional state or state of consciousness.

People should contact a doctor if they or a loved one experiences any of the symptoms of delirium.

Infections, chemical imbalances, and certain medications can cause delirium. Early diagnosis and prompt treatment may decrease the risk of future complications.