Delirium strikes most people in intensive care, yet is often mistaken for madness
Only 1 to 2 percent of people have delirium at any given time, yet it affects 81 percent of patients in intensive care. This sudden confusion is a sign that the body is under physical strain, and it is easily misread as a psychiatric illness such as psychosis or schizophrenia.
Doctors define delirium as an acute state of confusion that develops over hours or days and stems directly from a physical cause: a medical condition, a drug, or several factors together. Its core features are disturbed attention, awareness and wider thinking. Many patients also swing between agitation and sluggishness, sleep at the wrong times, or experience hallucinations and delusions, though none of these extras is needed for the diagnosis. The older label, acute confusional state, is now discouraged as too vague. In everyday speech the word gets used loosely for drowsiness or disorientation, but the clinical meaning is narrower.
The underlying brain disturbance is called an acute encephalopathy, and its trigger can lie inside the skull or elsewhere in the body. Infection or low oxygen can set it off, as can side effects of certain medications, intoxication with opioids or deliriant drugs, withdrawal from alcohol or sedatives, or a combination of problems such as pain and malnutrition. Symptoms produced purely by a psychiatric disorder, such as bipolar disorder, do not count.
Diagnosis is tricky because it depends on knowing how a person normally thinks. Delirium overlaps with dementia, depression and psychosis, and it can appear on top of those conditions. Getting it wrong has consequences: treating it as a different disorder with the wrong drugs can be dangerous, even fatal.
Figures quoted in the DSM-5-TR show the scale in hospitals. Between 18 and 35 percent of adults arriving at hospital have it, and 29 to 65 percent of inpatients develop it; after surgery the rate among older adults is 11 to 51 percent. For people in critical care it signals a higher risk of dying within a year. Management centres on finding and treating the cause. Antipsychotics are not supported for routine prevention or treatment in hospital, while bundles of non-drug care have evidence behind them for lowering risk.
Source: Delirium
