Rotation Prep

Published July 10, 2019


Delirium is an acute fluctuating change in mental state usually due to some reversible causes. Delirium is common: 30% of older adults hospitalized on a medical unit will become delirious, and 10% to 50% of older adults undergoing surgery will experience delirium.

Delirium is associated with increased mortality and morbidity. Among hospitalized patients, it is associated with up to a tenfold increase in mortality. Even post-hospitalization, individuals who developed delirium are more likely to have poor functional outcomes and higher risk for death.

Guiding Questions

  • How does one differentiate dementia from delirium?

  • What are the risk factors for delirium?

  • What role do nonpharmacologic and pharmacologic therapies play in the treatment of delirium?

Differential Diagnosis

Delirium must be differentiated from dementia. A number of screening tools are used to detect delirium; a commonly used tool is the Confusion Assessment Method (CAM).


Differential diagnosis for delirium is broad. Common causes for delirium in the elderly include harmful side effects from medications (e.g., opioids and benzodiazepines). Infectious causes should also be strongly considered.

Differential Diagnosis for Patients with Delirium



The key to management of delirium is to promptly recognize, evaluate, and offer nonpharmacological interventions.

Learn more about how to evaluate and manage delirium here (subscription required).
For more on delirium, see Altered Mental Status in the Neurology rotation guide.

NEJM Knowledge+