Delirium and dementia both disrupt cognition and have similar symptoms. However, these are two distinct conditions with different causes, progression, outlook, and treatment.
Altered mental status is a general term that refers to behavior changes caused by a disruption in how the brain works. It is common in older adults.
It encompasses various presentations, including inattention, confusion, disorientation, poor memory, incoherent speech, agitation, and psychosis.
Altered mental status is common in individuals with delirium and dementia. The two conditions may also coexist.
This article explores delirium and dementia, their similarities and differences, causes, diagnosis, and treatment.
Delirium is a disturbance in a person’s thoughts, mood, and behavior. It causes inattention, distractibility, disorganized thinking, and confusion. A person may have reduced awareness of their environment and may experience hallucinations or delusions.
Delirium may occur at any age but is more common in older adults and hospitalized individuals. Between
The most common type is Alzheimer’s disease, which occurs in 60–80% of cases. People with Alzheimer’s often have trouble remembering recent events and may experience personality changes in later stages of the disease.
Strokes and blood-flow issues to the brain cause about 10% of dementia cases, known as vascular dementia.
Most people with dementia begin to show symptoms after 65 years of age, but the condition is not an expected part of aging.
Many of the symptoms of delirium and dementia are similar and can cause similar consequences, such as people falling, getting lost, or becoming injured. At the same time, delirium is a risk factor for subsequent dementia.
In some cases, a person may have both. People with dementia are at a higher risk of having delirium.
People with delirium have an altered awareness that mainly affects their attention. They may have problems focusing, holding, and shifting attention. Meanwhile, dementia mainly affects memory.
Symptoms of delirium often develop within hours or days. They
They also tend to lessen during the day and worsen when it is dark or when the environment is unfamiliar.
Common signs and symptoms include:
- inattention, or difficulty focusing, shifting, or maintaining attention
- disorientation, or not knowing who and where they are, or what time it is
- slurred, incoherent, or rambling speech
- emotional changes, including anxiety, irritability, anger, depression, and fear
- sudden mood shifts
- restlessness, agitation, or aggression
- perceptual distortions, such as hallucinations or delusions
- being quiet, withdrawn, drowsy, or lethargic
- disturbed sleeping and eating habits
- personality changes
Symptoms may vary depending on the type of delirium a person has. Experts have identified
- Hyperactive delirium: This type is the most easily recognizable for its motor symptoms, including agitation, restlessness, and sometimes aggressiveness. A person with this type may have rapid mood shifts, hallucinations, and refuse to cooperate with their care.
- Hypoactive delirium: This type is known for reduced motor activity or inactivity. Common symptoms include sluggishness, slow speech, and apathy. A person with this type may also appear sedated.
- Mixed delirium: This type presents with symptoms of both hypoactive and hyperactive delirium. They may switch from one state to the other.
According to the
- visual perception
- judgment, reasoning, and problem-solving
Some signs that may indicate a person has dementia include:
- forgetting the names of close family and friends
- being unable to complete tasks independently
- getting lost in their neighborhood
- forgetting older memories
- forgetting the names of familiar objects
Side-by-side comparison of symptoms
See the table below for a side-by-side comparison of delirium versus dementia symptoms:
|Onset||abrupt onset with a definite beginning point||slow and gradually progressive, with an unclear starting point|
|Duration||days to weeks, but may be longer||months to years, usually permanent except for reversible causes of dementia, such as thyroid dysfunction, vitamin B12 deficiency, and normal pressure hydrocephalus|
|Course||often temporary and reversible when doctors identify and treat the cause||slow, persistent, and progressive course; incurable|
|Symptom fluctuation||fluctuates frequently and significantly throughout the day||attention and thinking skills are relatively constant throughout the day|
|Cause||specific illnesses such as urinary tract infection (UTI), dehydration, drug use, or drug and alcohol withdrawal||typically, conditions such as Alzheimer’s disease, frontotemporal dementia, vascular dementia, or other related disorders|
|Perceptual disturbances||very common||occasionally occur|
|Behavior/mood||usually causes combativeness and anger||usually causes depression, often with anxiety|
|Effect on attention||significantly impaired; abrupt reduction in awareness of environment and orientation||generally alert in the early stages; affected much later when dementia is already severe|
|Effect at night||nighttime almost always worsens symptoms||often worsens symptoms|
|Consciousness||varies||not affected until dementia has become severe|
|Language||slow, inappropriate, and incoherent||word-finding difficulty|
|Memory||typically less affected||significantly affected throughout the course of the disease, especially recent memory|
|Activity level||either overly active or underactive||not affected until later stages|
|Need for medical attention||requires immediate treatment||necessary but not urgent|
|Effect of treatment||often resolves with treatment||helps slow the progression of the disease but does not cure it|
Scientists believe the deterioration of specific brain cells causes dementia. This is a risk factor for delirium. People with dementia are especially at risk of experiencing sudden and severe cognitive and behavioral problems when they have an illness such as an infection. Delirium is one of the most common early symptoms of COVID-19 infection in people with dementia.
Delirium is also a risk factor for dementia because repeated episodes of temporary impairment of brain function make the brain cells
The following are more specific causes of delirium and dementia.
Various factors cause delirium. These include:
- infections, such as untreated UTIs
- electrolyte imbalances caused by dehydration and thyroid dysfunction
- sensory or sleep deprivation
- surgery or hospitalization
- metabolic disorders
- infections, such as pneumonia and the flu
- organ failure, including kidney or liver failure
- brain, heart, lung, and liver conditions, such as congestive heart failure and chronic obstructive pulmonary disease
- unfamiliar environment
- intoxication or withdrawal from alcohol or drugs
Dementia is a neurodegenerative process with a progressive loss or damage of nerve cells in the brain. This prevents various areas of the brain from communicating with each other.
Specific changes in the brain also cause dementia.
There are various risk factors for both delirium and dementia.
Who gets delirium?
Having the following
- over 70 years of age
- brain disorders such as dementia
- alcohol intoxication
- multiple coexisting disorders
- taking multiple medications
Who gets dementia?
Medical professionals consider dementia a late-life condition because it tends to occur in older people. It often affects people aged
People with siblings or parents with dementia are more likely to have dementia.
- high cholesterol
- high blood pressure
- a history of stroke, heart disease, or vascular disease
- poor diet
- fewer years of education
- lack of physical activity
- air pollution
- head injuries
- hearing loss
- social isolation
Healthcare professionals follow different procedures when diagnosing delirium and dementia. These are listed below.
Delirium requires an urgent evaluation.
To diagnose it, a doctor looks at a person’s history, physical exam, and medical and lab test results. These will help the doctor determine whether the change in the person’s mental status is a direct consequence of an underlying medical condition or certain factors such as toxin exposure.
Doctors use the Confusion Assessment Method (CAM) to identify the presence of delirium. CAM includes four main features:
- acute onset and fluctuating course of symptoms
- disorganized thinking
- altered level of consciousness
A doctor will run tests to rule out other possible conditions causing the symptoms. A neurologist will conduct thorough cognitive and neurological testing to evaluate the person’s mental abilities.
They may also request brain scans to identify conditions that may cause symptoms like those of dementia. These scans may also see changes in the brain’s structure and function. These include:
A doctor may sometimes ask for genetic testing, such as in Huntington’s disease and early and late cases of Alzheimer’s disease.
There are different treatment pathways for delirium and dementia. Read on to find out more.
Treatment of delirium involves identifying and addressing its underlying cause. This could include discontinuing medication or treating an infection.
Healthcare professionals may also focus on addressing complications caused by delirium, including improving nutrition, sleep, and pain management.
Doctors may also give medications to people with hyperactive delirium if the doctor feels the person or others are at risk.
Dementia has no cure, but treatment may help manage symptoms. Two drugs approved by the Food and Drug Administration (FDA) can help treat dementia:
- cholinesterase inhibitors (galantamine, rivastigmine, donepezil)
There are also non-drug treatments that may help improve or maintain cognitive function. These include:
- physical activity
- cognitive exercises
- memory training
- social stimulation
Besides dementia and delirium, several other brain conditions may lead to difficulties in thinking, behavior, and memory. These include:
Families and caregivers should immediately inform their doctors if a person they care for is displaying symptoms of delirium or is acting differently from their usual behavior.
It is also important to report anything that can help a healthcare professional identify the condition’s underlying cause. These include:
- all medications the person is taking, including those they recently started or stopped
- any environmental changes
- any health changes, including removal of hearing aids, and changes in sleep, bowel, or bladder habits
It is also essential to ensure a person experiencing delirium is comfortable. They should have a calming environment and get enough nutrition, rest, and sleep.
Delirium is preventable in
Delirium due to certain conditions such as drug or alcohol misuse and electrolyte imbalance typically resolves with treatment.
However, delirium may
Delirium and dementia are two conditions often used interchangeably or mistaken for each other. While they have several similarities, they have many characteristics that distinguish them.
Recognizing the difference between the two can help doctors provide adequate care. It can also inform family members and caregivers about their loved ones and how to best care for them.