Delirium occurs when the normal sending and receiving of signals in the brain becomes impaired. This impairment is most likely caused by a combination of factors that make the brain vulnerable and trigger a malfunction in brain activity.

Any condition that results in a hospital stay, especially in intensive care, increases the risk of delirium. Common causes include dehydration and infections, such as urinary tract infection, pneumonia, and skin and abdominal infections. Examples of other conditions that increase the risk of delirium include:

  • Dementia
  • Older age
  • Fever and acute infection, particularly in children
  • Previous delirium episodes
  • Visual or hearing impairment
  • Poor nutrition or dehydration
  • Severe, chronic or terminal illness
  • Multiple medical problems or procedures
  • Treatment with multiple drugs
  • Alcohol or drug abuse or withdrawal

A number of medications or combinations of medications can trigger delirium, including some types of:

  • Pain medications
  • Sleep medications
  • Allergy medications (antihistamines)
  • Medications for mood disorders, such as anxiety and depression
  • Parkinson's disease medications
  • Drugs for treating spasms or convulsions
  • Asthma medications

Delirium may have more than one cause, such as a medical condition and medication toxicity.

Aug. 15, 2012