Updated from the original publication on July 8, 2016.
If you care for a senior with cognitive impairment, you may have heard several names for the condition — including dementia, delirium and Alzheimer’s disease. But the truth is that the three terms are not interchangeable, and correct diagnosis is critical for ensuring proper medical care.
Dementia, Delirium and Alzheimer’s: What’s the Difference?
Cognitive impairment most commonly is caused by either delirium or dementia, and the two conditions can be tough to tell apart. Both conditions involve disordered cognition, but delirium primarily impacts attention, while dementia primarily affects memory.
Alzheimer’s, meanwhile, is a specific form of dementia and is classified as a disease. Dementia refers to a set of symptoms impacting mental tasks, including reasoning and memory. A number of different conditions — including Alzheimer’s disease — can cause dementia.
Causes and Symptoms
While dementia and delirium can present with similar symptoms — primarily mental confusion — the causes serve as one differentiating factor. Drug toxicity or acute illness most often cause delirium, which tends to begin quickly and often can be reversed. On the other hand, physical changes in the brain typically bear responsibility for Alzheimer’s or another form of dementia, which develops more slowly and generally cannot be reversed.
Patients suffering with dementia often develop delirium, but mistaking the two conditions can have serious health consequences for seniors. In a case of delirium, a senior may suddenly demonstrate problems with paying attention or focusing. The condition also can cause other symptoms, including trouble with language and memory, disorientation and hallucinations. Symptoms often seem to get better and worse over short periods of time.
The stress of a hospital stay can trigger delirium in seniors. In addition, some medical problems, including urinary tract infections, can cause delirium. And because seniors suffering from a urinary tract infection often show symptoms of confusion and agitation, the infection may be mistaken for delirium or dementia — potentially going untreated as a result.
Proper Diagnosis and Treatment Are Critical
Even if a senior already receives treatment for Alzheimer’s or another form of dementia, properly diagnosing and treating delirium remains important. Delirium serves as a symptom of stress to the body and mind but does not reveal the underlying cause — such as pain or an infection.
Delirium also can cause or exacerbate additional health conditions, including a heightened risk for falls or other injuries. And research has found that delirium independently increases the time spent in the hospital and the risk of dying while hospitalized. It also can worsen and accelerate cognitive decline.
When to Consult a Doctor
Dementia — including Alzheimer’s disease — and delirium can look very similar, and a senior can suffer from both at the same time. For an individual already diagnosed with dementia, the risk of delirium increases in certain situations such as hospitalizations and in the presence of other illnesses. If your loved one shows any signs of delirium, see a doctor immediately; your observations of behavioral changes and other symptoms will be critical for a proper diagnosis.
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