Clinical meaning
Delirium is an acute, fluctuating disturbance in attention and cognition that develops over hours to days and represents an underlying medical emergency. Unlike dementia which develops gradually and is irreversible, delirium has rapid onset, fluctuating course, and is potentially reversible when the underlying cause is treated. The mnemonic I WATCH DEATH identifies common causes: Infections, Withdrawal, Acute metabolic, Trauma, CNS pathology, Hypoxia, Deficiencies, Endocrine, Acute vascular, Toxins/medications, Heavy metals. Hypoactive delirium (quiet, withdrawn) is frequently missed compared to hyperactive delirium (agitated, hallucinating). The Confusion Assessment Method (CAM) is the validated screening tool.
Exam relevance
Risk factors: - Advanced age (>65 years) with cognitive vulnerability - Acute infection (UTI most common cause in elderly) - Medication changes or polypharmacy (anticholinergics, opioids, benzodiazepines) - Postoperative state especially after hip fracture repair - Dehydration, electrolyte imbalances, or metabolic disturbances