Delirium

Overview


Plain-Language Overview

Delirium is a sudden change in brain function that causes confusion, difficulty paying attention, and problems with memory and thinking. It affects the brain, which controls how a person thinks, feels, and behaves. People with delirium may become very restless, sleepy, or have trouble understanding what is happening around them. This condition often develops quickly, over hours to days, and can fluctuate throughout the day. It is commonly seen in older adults or those who are very sick. The main health impact is that it disrupts normal mental function, making it hard to communicate or care for oneself safely. Recognizing delirium early is important because it often signals an underlying medical problem.

Clinical Definition

Delirium is an acute neuropsychiatric syndrome characterized by a disturbance in attention, awareness, and cognition that develops over a short period, usually hours to days. It results from an underlying medical condition, substance intoxication or withdrawal, or exposure to toxins, leading to widespread cerebral dysfunction. The pathophysiology involves disruption of neurotransmitter systems, particularly decreased acetylcholine and increased dopamine activity, as well as neuroinflammation and oxidative stress. Clinically, it presents with fluctuating levels of consciousness, impaired attention, disorganized thinking, and perceptual disturbances such as hallucinations. It is a common complication in hospitalized and critically ill patients and is associated with increased morbidity, mortality, and longer hospital stays. Prompt identification and management of the underlying cause are critical to improving outcomes.

Clinical Presentation


Diagnostic Workup


Pathophysiology


Treatments


Prevention


Outcome & Complications


Differential Diagnoses


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