Table 2.

Differential diagnosis

Differential	Rationale	Description
Cefepime-induced neurotoxicity	The onset of AMS after cefepime is typical in renal impairment	AMS resolved after cefepime was discontinued
Hospital-acquired delirium	ICU stay, infection, and advanced age	No other delirium triggers identified; resolved post-cefepime
Subclinical seizures	AMS without convulsions	Long-term EEG monitoring ordered
Stroke	Sudden-onset AMS	The MRI of the brain was unremarkable
Shunt malfunction or over-drainage	Recent shunt adjustments; prior history	CT head stable; neurosurgery signed off