376 Ch 375. Confusional States and Delirium

Delirium = acute confusional state — (1) acute onset (hours-days) + fluctuating course, (2) inattention (hallmark), (3) disorganized thinking or altered LOC, (4) caused by underlying medical condition/drug/withdrawal/multifactorial (DSM-5);SUBTYPES: hyperactive (agitated) vs hypoactive (lethargic — often missed, worse prognosis) vs mixed；epidemiology: ~ 20% of hospitalized older adults; 50-80% of ICU patients; 30% of post-surgical elderly；risk factors: age > 65, dementia, prior delirium, multi-comorbidity, severe illness, sensory impairment；precipitants: medications (most common — anticholinergics, BZDs, opioids), infection, electrolyte/metabolic, surgery, ICU stay, dehydration, pain, urinary retention/constipation, sleep deprivation；workup: history + meds + exam + CAM/CAM-ICU + labs (electrolytes, glucose, infection, drug levels) + selective imaging；treatment: identify + treat underlying + non-pharm first (reorientation, sleep, mobility, hydration, sensory aids — HELP program) + minimize culprit drugs + pharm only for severe agitation (low-dose haloperidol or atypical antipsychotic; AVOID benzodiazepines unless alcohol/BZD withdrawal)；consequences: prolonged hospital stay + ↑ mortality + ↑ institutionalization + accelerated cognitive decline。