Memory & behavior

Confusion vs. delirium (when it’s urgent)

Delirium is a sudden change in thinking/alertness and can be a medical emergency. This page helps you recognize it and act fast.

Quick checklist

  • Delirium is usually sudden (hours–days). Dementia is usually gradual (months–years).
  • If the change is sudden, treat it as urgent until proven otherwise.
  • Check for infection, dehydration, medication changes, and recent falls.
  • If they’re unsafe or rapidly worsening, seek urgent care.

Red flags (urgent)

  • Sudden severe confusion or agitation.
  • New inability to stay awake or severe drowsiness.
  • Confusion after a fall or head injury.
  • Fever, breathing trouble, chest pain, or one-sided weakness.

What to document

  • When it started, what changed, and any new meds/illness.
  • Baseline behavior vs current behavior.
  • Fluid intake, urination changes, and sleep.