True statement regarding delirium includes
**Core Concept**
Delirium is a complex neuropsychiatric syndrome characterized by acute onset of fluctuating cognitive impairment, often accompanied by altered level of consciousness, agitation, and difficulty with sleep-wake cycles. It is a common complication in hospitalized patients, particularly those with underlying medical conditions, substance use disorders, or taking multiple medications.
**Why the Correct Answer is Right**
Delirium is often precipitated by identifiable risk factors, including medication side effects, infection, metabolic disturbances, and withdrawal from substances. The pathophysiology of delirium involves disruptions in normal neurotransmitter function, particularly the imbalance of dopamine and acetylcholine, leading to impaired attention and executive function. This complex interplay is further exacerbated by age-related changes in brain anatomy and function.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because delirium is not typically associated with a single cause, but rather a multifactorial interplay of predisposing, precipitating, and perpetuating factors.
**Option B:** This option is incorrect because delirium is not a normal response to environmental stressors, such as a new hospital environment, but rather a pathological state requiring medical attention.
**Option C:** This option is incorrect because delirium is not a diagnosis of exclusion, but rather a clinical syndrome that requires a comprehensive evaluation to identify underlying causes.
**Clinical Pearl / High-Yield Fact**
When assessing a patient for delirium, it is essential to consider the "4 A's": acute onset, altered level of consciousness, agitation, and attention deficit. This mnemonic can help clinicians quickly identify patients at risk for delirium and guide further evaluation and management.
**Correct Answer:** A.