Consciousness - decreased
Alternative Names: Stuporous; Mental status - decreased; Loss of alertness; Decreased consciousness; Alertness - decreased; Changes in consciousness; Obtundation; Coma; Unresponsiveness
Decreased consciousness is reduced alertness or awareness.
A persistent coma is called vegetative state.
Causes of Consciousness - decreased
Many conditions can cause decreased consciousness, including:
- Alcohol intoxication
- Drug intoxication (particularly opiates, narcotics, sedatives, and anti-anxiety or seizure medications)
- 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
- Head trauma
- Heart failure
- Hypoglycemia (low blood sugar)
- Increased carbon dioxide levels (hypercarbia) often seen in emphysema
- Low blood pressure (hypotension)
- Metabolic disorders
- Thyroid or adrenal gland disorders
- Seizures such as those related to epilepsy
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.
When to Contact a Health Professional
See medical help if someone has unexplained, decreased consciousness. Call your local emergency number (such as 911) if normal consciousness does not return quickly.
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?
- 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
- 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.
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.
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.
Copyright 2011 A.D.A.M., Inc.