An older adult client enjoys good overall health, but has just been diagnosed with pneumonia and has begun receiving an intravenous (IV) antibiotic. Shortly after being administered the first dose, the client pulled out his IV line and is now attempting to scale his bed rails. Which of the following phenomena most likely underlies this change in the client's cognition?
A) Dementia
B) Depression
C) Disorientation
D) Delirium

D. Delirium

Explanation:

In medicine and psychology, delirium is defined as a disturbed state of mind that is most usually caused by high fever, drug interactions, intoxication. The signs of delirium are incoherence in behaviors and thoughts as well as paranoid thoughts or recklessness.

In this example, an older adult with good overall health receives an antibiotic, shortly after receiving the first dose he pulls out his IV line and attempts to scale his bed rails. He most likely is experiencing delirium (since he is showing incoherence in behaviors and thoughts) and he just got an antibiotic so he might be experiencing this because of this drug.