A 68-year-old client who is hospitalized with pneumonia is disoriented and confused 3 days after admission. Which information indicates that the client is experiencing delirium rather than dementia?

Choice A reason: Seasonal Affective Disorder (SAD) is a subtype of major depressive disorder with a seasonal pattern, requiring at least two major depressive episodes in a seasonal pattern over two years, not necessarily five key features for two weeks. The diagnostic criteria involve symptoms like low mood, anhedonia, and fatigue, but the two-week duration with five symptoms applies to major depression generally, not specifically SAD, which emphasizes seasonal recurrence.

Choice B reason: The statement is false because Seasonal Affective Disorder is defined by recurrent depressive episodes tied to specific seasons, typically winter, rather than a strict requirement of five key features for two weeks. SAD involves symptoms like hypersomnia and carbohydrate craving, but the diagnostic focus is on the seasonal pattern, not the exact symptom count or duration stated.

Choice A reason: Orientation to person but disorientation to place and time occurs in both delirium and dementia. In delirium, acute cerebral dysfunction from causes like infection disrupts attention, while dementia’s gradual hippocampal loss affects memory. This symptom is non-specific, as it does not distinguish the acute onset critical to delirium diagnosis.

Choice B reason: Fragmented, incoherent speech can occur in delirium due to acute brain dysfunction or in advanced dementia from cortical degeneration. It reflects disrupted neural communication but is not specific to delirium’s rapid onset. This symptom alone does not differentiate the conditions, as both involve cognitive processing deficits.

Choice C reason: A history of increasing confusion over years indicates dementia, characterized by progressive neuronal loss, particularly in Alzheimer’s or vascular dementia. Delirium, conversely, has an acute onset due to reversible causes like infection. This chronic history rules out delirium, making this choice incorrect for identifying delirium.

Choice D reason: Being oriented and alert on admission, then developing confusion, indicates delirium’s acute onset, typically from pneumonia-related hypoxia or sepsis disrupting cerebral metabolism. Unlike dementia’s gradual progression, delirium’s rapid cognitive decline, often within days, reflects reversible brain dysfunction, making this the key differentiator in diagnosis.