Intense nihilism, somatization and agitation in old age are the hallmark symptoms of
**Core Concept**
Delirium is a neuropsychiatric syndrome characterized by acute onset of cognitive impairment, fluctuating course, and altered level of consciousness. It often presents with intense nihilism, somatization, and agitation in older adults. The underlying pathophysiology involves disturbances in neurotransmitter regulation, particularly the cholinergic and dopaminergic systems.
**Why the Correct Answer is Right**
Delirium is a state of acute cognitive decline that can be precipitated by various factors such as infections, medications, or metabolic disturbances. The intense nihilism, somatization, and agitation observed in patients with delirium are thought to result from the disruption of normal neurotransmitter function. Specifically, the cholinergic hypothesis suggests that delirium is associated with decreased acetylcholine levels in the brain, leading to impaired attention and cognitive processing. The dopaminergic system is also implicated, as alterations in dopamine levels can contribute to the development of delirium.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the hallmark symptoms of delirium. While apathy can be a feature of delirium, it is not the primary characteristic.
**Option B:** This option is incorrect because it is a type of dementia characterized by gradual cognitive decline, rather than acute onset and fluctuating course seen in delirium.
**Option C:** This option is incorrect because it refers to a mood disorder that can present with somatic symptoms, but does not account for the intense nihilism and agitation characteristic of delirium.
**Clinical Pearl / High-Yield Fact**
Delirium is a medical emergency that requires prompt recognition and treatment. The "CAM" (Confusion Assessment Method) is a widely used tool for identifying delirium in clinical settings.
**Correct Answer:** D.