Decreased alertness is a state of reduced awareness.

A coma is a state of decreased alertness from which a patient cannot be awakened. A long-term coma is called a vegetative state.

See also:

• Delirium
• Dementia

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

Many conditions can cause decreased alertness, including:

• Chronic kidney disease
• Extreme tiredness or lack of sleep
• High blood sugar or low blood sugar
• Infection that is severe or involves the brain
• Liver failure
• Thyroid conditions that cause low thyroid hormone levels or very high thyroid hormone levels

Brain disorders or injury, such as:

• Dementia or Alzheimer's disease
• Head trauma
• Seizure
• Stroke

Injury or accidents, such as:

• Diving accidents and near drowning
• Heat stroke
• Very low body temperature (hypothermia)

Heart or breathing problems, such as:

• Abnormal heart rhythm (arrhythmia)
• Lack of oxygen (hypoxia) from any cause
• Low blood pressure (hypotension)
• Low sodium levels in the blood
• Severe heart failure
• Severe lung diseases
• Very high blood pressure

Toxins and drugs, such as:

• Alcohol abuse (binge drinking or damage from long-term alcohol use)
• Exposure to heavy metals, hydrocarbons, or toxic gases
• Overuse of drugs such as opiates, narcotics, sedatives, and anti-anxiety or seizure medications
• Side effect of almost any medicine, such as those used to treat seizures, depression, psychosis, and other illnesses

Review Date: 04/03/2011
Reviewed By: Jacob L. Heller, MD, MHA, Emergency Medicine, Virginia Mason Medical Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)