The Confused Patient: Delirium and Dementia

Delirium

Delirium is an acute process that reflects medical problems, particularly in elderly, brain-injured, or acutely ill patients and in children.

Signs and symptoms of delirium include the following:

• Inattention

• Disorientation to person, place, time, or situation

• Fluctuations in consciousness

• Mood or speech that is inappropriate to situation

• Hallucinations or delusions

• Alterations in the sleep-wake cycle

• Fluctuation in symptoms

• Psychomotor agitation or retardation

Delirium is characterized by rapid onset, although sometimes the patient will show prodromal behavioral disturbances up to several days before frank delirium sets in. These can include irritability, anxiety, sleep disturbances, and lethargy.

Delirium usually has a fluctuating course (“waxing and waning”) ranging from clouding of consciousness to coma interrupted by lucid intervals. It can have a duration lasting from minutes to weeks. Typically, symptoms of delirium worsen at night (“sundowning”). “Sundowning” is typical in the elderly and is characterized by disorientation at night, falls, wandering, illusions, or hallucinations.

Disturbances of the sleep-wake cycle and an increased or decreased level of psychomotor activity are hallmarks of the delirium, but features vary widely, often making the diagnosis more difficult.

Global impairment of cognition occurs, causing disturbances in memory, perception, and thinking. Delirious patients often have a reduced ability to remain focused, leading to easy distractibility. They may demonstrate disorganized thinking, incoherent speech, and sensory misperceptions, especially visual hallucinations and illusions.

The delirious patient can be either agitated or apathetic, reflecting psychomotor agitation or retardation. Patients may be restless, pick at their bedclothes (“floccillation” or carphology), or try to get out of bed. The physician on call is much more likely to be called for a delirious patient who is combative and agitated, whereas the “quietly” delirious patient may be overlooked or regarded as depressed and withdrawn.

Emotional disturbances appear in the form of depressed mood, anxiety or fear, paranoia, irritability, euphoria, or apathy. Lability of affect is manifested by rapid shifts between crying, laughter, fear, and anger. Thus, if a patient is described as confused or disoriented, especially with concomitant flux in mood or behavior, delirium is a likely diagnosis.

Sympathetic hyperactivity may occur, including tachycardia, diaphoresis, flushed face, dilated pupils, and elevated blood pressure.

Dementia

Dementia is the decline of higher cortical functions, especially memory, thinking, orientation, comprehension, calculation, learning capacity, language, and judgment. The dysfunction is sufficient to impair activities of daily living and social activities. Although it can occur at any age, dementia is most common in the elderly. Alzheimer’s dementia, the most common form of dementia, affects as many as 5.2 million Americans, or roughly 11% of the US adult population age 65 and older. The incidence doubles with every 5-year interval beyond age 65. It is the sixth leading cause of death in the United States and the fifth leading cause of death in Americans age 65 and older.

Unlike in delirium, consciousness is typically clear in dementia (i.e., the patient is alert). Depending on the etiology, dementia may have a sudden or insidious onset, be progressive with a long duration, be static, or have a remitting course.

Primary symptoms of dementia include memory loss, particularly difficulty in learning new information (immediate memory), recalling recent events (recent memory), and remembering past personal information (remote memory). Impairment in abstract thinking, judgment, and impulse control; neglect of personal appearance and hygiene; personality changes, anxiety, or depression; paranoid ideation; and irritability are all associated with dementia.

Pseudodementia

Pseudodementia is a severe type of major depression with symptoms similar to dementia, such as withdrawal, decline in concrete thinking, and loss of memory. History of a previous mood disorder, recent emotional distress, and loss of short-term and long-term memory may help distinguish pseudodementia from dementia.

Amnestic disorder

Amnestic disorder is characterized by memory impairment with no other cognitive deficits that affect occupational or social functioning. Because amnesia may have psychological or organic etiologies, it is important to take a careful history. Electroconvulsive therapy, psychological stress, or a recent traumatic event all may contribute to amnesia.

Phone call

Elevator thoughts

What are the causes of confusion in the patient you are about to see?

Differential diagnoses