**Question:** True about delirium are all, except: NEET 13

A. Delirium is a reversible condition
B. Delirium is a chronic neurological condition
C. Delirium is primarily caused by substance abuse
D. Delirium is a rare occurrence in the elderly population

**Core Concept:** Delirium is a neuropsychiatric syndrome characterized by acute and fluctuating impairments in attention, consciousness, and cognition. It is a common problem among hospitalized patients, affecting about 20% of critically ill patients and 25-50% of patients older than 70 years. Delirium can be categorized into subsyndromal delirium, hypoactive delirium, hyperactive delirium, and mixed delirium based on the patient's behavior and presentation.

**Why the Correct Answer is Right:**

Delirium is a reversible condition, which means that it can be treated and resolved once the underlying cause is addressed. For example, correcting electrolyte imbalances, managing pain, treating infections, and ensuring adequate sensory input can help resolve delirium. Since delirium is a reversible condition, options B, C, and D are incorrect.

**Why Option A is Incorrect:**

Option A (Delirium is a chronic neurological condition) is incorrect because delirium is a temporary and acute condition, typically lasting days to weeks, rather than months or years. It is often triggered by illness, injury, or medication side effects rather than being a chronic condition.

**Why Option B is Incorrect:**

Option B (Delirium is a chronic neurological condition) is incorrect because delirium is an acute neurological condition, not a chronic one. While some patients with delirium may have underlying chronic conditions that predispose them to develop delirium, the core concept of delirium is an acute event.

**Why Option C is Incorrect:**

Option C (Delirium is primarily caused by substance abuse) is incorrect because delirium can be caused by various factors, including substance abuse, but it is not primarily caused by substance abuse. Delirium can result from a wide range of factors, including infections, dehydration, electrolyte imbalances, and medication side effects.

**Why Option D is Incorrect:**

Option D (Delirium is a rare occurrence in the elderly population) is incorrect because delirium is a common problem among elderly patients, affecting up to 80% of patients aged over 80 years. However, delirium can occur in any age group and is not exclusive to the elderly population.

**Core Concept:** Delirium is a clinical syndrome characterized by acute and fluctuating changes in attention, awareness, and cognition. It is a common complication in hospitalized patients, affecting approximately 20-50% of patients and is associated with increased morbidity, mortality, and healthcare costs.

**Why Option A is Right:**

Option A (Delirium is a reversible condition) is right because delirium is typically an acute event caused by a specific trigger, such as infection, dehydration, medication side effects, or withdrawal from alcohol or drugs. By addressing the