What causes confusion?

Confusion may be associated with serious infections, some chronic medical conditions, head injury, brain or spinal cord tumor, delirium, stroke, or dementia. It can be caused by alcohol or drug intoxication, sleep disorders, chemical or electrolyte imbalances, vitamin deficiencies, or medications. It can also occur in the period following a seizure, called the postictal period, or as a result of hypothermia.

Common causes of confusion

Confusion may be caused by conditions including:

  • Anesthesia
  • Chemical or electrolyte imbalances
  • Chronic kidney disease (which includes any type of kidney problem such as kidney stones, kidney failure, and kidney anomalies)
  • Chronic liver disease (which includes any type of liver problem such as hepatitis, cirrhosis, and liver failure)
  • Chronic obstructive pulmonary disease (COPD, which includes emphysema and chronic bronchitis)
  • Congestive heart failure (deterioration of the heart’s ability to pump blood)
  • Dementia
  • Drug or alcohol intoxication
  • Medication side effects (recovery may take time after drug discontinuation)
  • Seizure disorders
  • Severe dehydration
  • Severe trauma
  • Sleep deprivation or disturbances
  • Vitamin deficiencies such as niacin, thiamine, vitamin B12, or vitamin C deficiency

Serious or life-threatening causes of confusion

In some cases, confusion may be a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting. These include:

  • Brain or spinal cord injury or tumor
  • Delirium
  • Drug or alcohol overdose
  • Encephalitis (inflammation and swelling of the brain due to a viral infection or other causes)
  • Heat stroke
  • Hypoglycemia (low blood sugar)
  • Kidney failure
  • Meningitis (infection of the membranes that cover the brain and spinal cord)
  • Hypothermia
  • Seizure
  • Sepsis (severe infection of the bloodstream)
  • Stroke

Questions for diagnosing the cause of confusion

To diagnose your condition, your doctor or licensed health care practitioner will ask you several questions related to your confusion including:

  • When did you first notice confusion?
  • Do you have any other symptoms?
  • Do you have any difficulty sleeping?
  • Did anything such as an injury or illness precede the symptoms?
  • Do you have any other medical conditions?
  • What medications are you taking? Are you taking any new medications?
  • Have you taken any street drugs?
  • Do you drink alcohol?

What are the potential complications of confusion?

Because confusion can be due to serious diseases, failure to seek treatment can result in serious complications and permanent damage. Once the underlying cause is diagnosed, it is important for you to follow the treatment plan that you and your health care professional design specifically for you to reduce the risk of potential complications including:

  • Difficulty swallowing
  • Paralysis or inability to move a body part
  • Permanent cognitive impairment
  • Permanent loss of sensation
  • Personality changes
  • Physical disability
  • Unconsciousness and coma


  1. NINDS dementia information page. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/dementias/dementia.htm.
  2. Confusion. Medline Plus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/ency/article/003205.htm.

What is confusion?

Confusion occurs when a person has difficulty understanding a situation or has disordered or unclear thoughts. It can be accompanied by memory loss, disorientation, or the inability to think quickly.

... Read more about confusionintroduction


What other symptoms might occur with confusion?

Confusion may accompany other symptoms, which vary depending on the underlying disease, disorder or condition. Symptoms that frequently affect the brain may also involve other body systems or disorders.

Infection symptoms that may occur along with confusion

Confusion may accompany symptoms related to infection including:

  • Enlarged lymph nodes Read more about confusionsymptoms

Medical Reviewer: William C. Lloyd III, MD, FACS Last Annual Review Date: Aug 9, 2013 Copyright: © Copyright 2014 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

This Article is Filed Under: Brain and Nerves