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A delirium is an acute confusional state where the affected person has lost control of judgment, reasoning, normal behavior and normal mood.

This acute confusional state can occur in a normal person or in a person who already had chronic intellectual impairment such as in dementia. The latter situation is more common.

The patient with in a delirium has a problem processing information from the environment such as sounds, pictures or behaviors. Perhaps part of the information is processed, but other parts are missed and the internal confusion may add to other false information, which leads to misinterpretations, illusions, delusional and paranoid thoughts.

Causes of delirium

There are four broad categories of causes, which can lead to an acute delirium: delirium due to an underlying metabolic disorder, due to toxic causes, due to infectious causes and due to structural causes. Under the links of “Alzheimer’s, dementia and delirium” I will comment regarding each of these categories.

 Delirium (With Hallucination)

Delirium (With Bizarre Hallucination)

Symptoms of delirium

As already mentioned above there is a clouding in of the consciousness. Symptoms vary from patient to patient and also according to the underlying cause.

The person affected is confused, does not remember the time, date or place. There is a change in personality. The mood fluctuates and can quickly change from extremely depressed to euphoric. There can be hallucinations, often of a visual type, but there are also inappropriate behaviors and fears. Some patients become very quiet and apathetic, others are agitated and pace around. The speech is often disturbed with slurring, newly made up words, disorganized sentences. The sleep/wake cycle is severely disturbed.

As about 20% of elderly patients die in a delirium, there is a great urgency to get the affected person to a hospital quickly to have the patient checked out regarding treatable conditions.

Diagnostic tests

The doctor will examine and will want to organize an emergency CT or MRI scan, which would visualize any structural lesion. Often a neurologist is needed for a work-up in general. Blood tests to rule out toxins or metabolic or electrolyte disturbances will be done. There might be other imaging studies necessary to rule out any of the structural causes. If structural brain abnormalities are found, a neurosurgeon would be needed as well.


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Last modified: October 2, 2014

This outline is only a teaching aid to patients and should stimulate you to ask the right questions when seeing your doctor. However, the responsibility of treatment stays in the hands of your doctor and you.