Delirium is one of the most frequently encountered medical conditions, and has a rapid and fluctuating progression. It results in deterioration of the person’s cognitive functions like attention and memory. It often occurs in patients who are hospitalized for a serious medical illnesses.
Delirium patients suffer a deterioration of their sleep-wake cycle (hyper-alertness or inaction, daytime sleepiness, night-time agitation/hyperactivity), a decline in their attention-memory functions and perceptual deficits (hallucinating, confusing people). Patients often get confused as to where they are, they may talk nonsensical, they may not recognize their attendants, and may appear angry or frightened.
Illnesses that can cause delirium are often medical disorders related to organs other than the brain (for example liver cirrhosis, severe cardiac insufficiency, serious disorders of the respiratory system, severe anaemia, major traumas to the body, major operations, serious infections). Less common causes of delirium are alcohol, certain sedatives and drugs, or a primary diseases of the brain (like encephalitis).
Delirium is often regarded as a symptom that indicates the severity of the underlying medical disorder. On the other hand, because of the wanton behaviour of the patient and the associated noncompliance with treatment, delirium can make treatment of the underlying disorder more difficult. When the underlying medical disorder is treated successfully, the delirium often regresses and shows signs of recovery. In order to achieve compliance with the medical treatment and reduce the risk of the patient inadvertently injuring himself, delirium is brought under control by the use of drugs called antipsychotics. In each case of delirium, it is of primary importance to investigate which medical reason has given rise to the delirium. This is done by various blood tests and imaging methods.