Q: What is delirium, and is it the same thing as dementia?
A: The two can have similar symptoms, but they are very different conditions. Dementia is a progressive illness marked by declines in memory, attention, decision-making ability, and other cognitive functions that eventually interfere with a person’s ability to perform daily activities (such as driving, dressing themselves, cooking, or going places alone). It usually develops gradually, over the course of many months or years. Alzheimer’s disease is the most common cause of dementia. Dementia can also result from multiple mini-strokes (TIAs), in which case it’s called vascular dementia.
Related: Who Needs Alzheimer’s Testing?
Delirium, in contrast, is an acute syndrome brought on by a specific underlying cause. Like dementia, it commonly affects older adults and is characterized by changes in attention, self-awareness, and memory function. But the onset is rapid, over the course of hours or days, with mental status sometimes improving and then worsening again within a single day (psychiatrists call this waxing and waning). Delirium is considered a medical emergency because it is almost always caused by one or more conditions that need immediate attention. Common causes include urinary tract or pulmonary infections, substance intoxication or withdrawal, electrolyte disturbance, low blood sugar, liver disease, medication side effects or interactions, and head trauma. Delirium also sometimes occurs in hospital patients, who can become disoriented by lack of sleep (thanks to loud noise, bright lights, and forced wakeups), effects of medication (especially sedatives), stress, and the toll of the illness itself.
Signs of delirium include difficulty concentrating or answering questions, hallucinations, and an inability to stay awake. The person may also become agitated and refuse to follow directions from others, such as nurses. A person exhibiting these signs should be brought to a medical clinic or emergency room as soon as possible. You should expect the clinician to ask detailed questions about the onset of the delirium, any other symptoms or signs associated with it, and what medications or substances the person has used recently. The doctor may also order blood tests, a chest x-ray, head imaging, or an electrocardiogram.
The main treatment for delirium is to treat the underlying medical cause or causes, once they’re identified. The treating physician may also prescribe antipsychotic medication to control agitation and hallucinations until the underlying problem is resolved. Once it is, the patient should return to their pre-delirium state—unless the causative event itself resulted in brain damage (head trauma, for example), in which case the mental symptoms may not be reversible.
Also see Fighting Dementia: Yes We Can.