Consciousness - decreased

• Alternative Names

  Stuporous; Mental status - decreased; Loss of alertness; Decreased consciousness; Alertness - decreased; Changes in consciousness; Obtundation; Coma; Unresponsiveness

• Considerations

  A persistent coma is called vegetative state.

• Common Causes

  Many conditions can cause decreased consciousness, including:

  • Alcohol intoxication
  • Drug intoxication (particularly opiates, narcotics, sedatives, and anti-anxiety or seizure medications)
  • Arrhythmia
  • Brain disorders
  • Central nervous system diseases
  • Lack of oxygen (hypoxia)
  • Abnormal blood sugars (diabetic coma)
  • Electrolyte or mineral imbalance
  • Exposure to heavy metals or hydrocarbons
  • Extreme fatigue or sleep deprivation
  • Ketoacidosis
  • Head trauma
  • Heart failure
  • Hypoglycemia (low blood sugar)
  • Increased carbon dioxide levels (hypercarbia) often seen in emphysema
  • Infection
  • Low blood pressure (hypotension)
  • Metabolic disorders
  • Thyroid or adrenal gland disorders
  • Seizures such as those related to epilepsy
  • Shock
  • Stroke
• Home Care

  A decrease in consciousness almost always require a doctor's attention, except perhaps when due to alcohol intoxication, simple fainting, or a previously recognized seizure disorder.

  See the article on seizures for tips on how to care for a person who is having a seizure.

  Persons with epilepsy or other seizure disorder should carry a Medic-Alert bracelet or pendant describing their condition. Such individuals should avoid situations that have previously triggered a seizure.

• Call your health care provider if

  See medical help if someone has unexplained, decreased consciousness. Call your local emergency number (such as 911) if normal consciousness does not return quickly.

• What to expect at your health care provider's office

  Most often, a person with decreased consciousness will be evaluated in an emergency room setting.

  The doctor will perform a physical examination. The exam will include a detailed look at the cardiovascular, respiratory, and nervous systems.

  The health care team will ask questions about the person's medical history and symptoms, including

  • Time pattern
    • When did the decreased consciousness occur?
    • How long did it last?
    • Has it ever happened before? If so, how many times?
    • Did the person behave the same way on previous episodes?
  • Medical history
    • Does the person have known epilepsy or seizure disorder?
    • Does the person have diabetes?
    • Has the person been sleeping well?
    • Has there been a recent head injury?
  • Other
    • What medications does the person take?
    • Does the person habitually use alcohol or drugs?
    • What other symptoms are present?

  Tests that may be done include:

  • Complete blood count or blood differential
  • Electrolyte panel
  • CT scan or MRI of the head
  • ECG (electrocardiogram)
  • EEG (electroencephalogram)
  • Chest x-ray
  • Urinalysis
  • Toxicology panel

  Treatment depends on the underlying cause of the decreased consciousness. How well a person does depends on the cause of the condition. The longer the person has a decreased or altered level of consciousness, the worse the outcome.

• References

  Blok BK, Newman TM. Syncope. In: Tintinalli JE, Kelen GD, Stapczynski JS, Ma OJ, Cline DM, eds. Emergency Medicine: A Comprehensive Study Guide. 6th ed. New York, NY: McGraw-Hill; 2004:chap 52.

  Huff JS. Altered mental status and coma. In: Tintinalli JE, Kelen GD, Stapczynski JS, Ma OJ, Cline DM, eds. Emergency Medicine: A Comprehensive Study Guide. 6th ed. New York, NY: McGraw-Hill; 2004:chap 259.

  Kirsch TD. Head injury. In: Tintinalli JE, Kelen GD, Stapczynski JS, Ma OJ, Cline DM, eds. Emergency Medicine: A Comprehensive Study Guide. 6th ed. New York, NY: McGraw-Hill; 2004:chap 255.

Review Date: 4/21/2009

Reviewed By: Jacob L. Heller, MD, Emergency Medicine, Virginia Mason Medical Center, Seattle, Washington, Clinic. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.