Decreased consciousness may result from a multitude of conditions including intoxication (drug, alcohol, or toxin), metabolic abnormalities, seizure activity (epilepsy), central nervous system diseases and conditions, head trauma, shock, decreased oxygen (hypoxia), and decreased blood pressure (hypotension).

Decrease in consciousness, unconsciousness, and coma almost always require medical evaluation (with the possible exception of alcohol intoxication, simple fainting, or a previously recognized seizure disorder).

Persistent coma is called vegetative state.

• head trauma
• extreme fatigue or sleep deprivation
• seizure activity
• stroke (CVA)
• heart failure
• arrhythmia
• diabetic coma (diabetic hyperglycemic hyperosmolar coma)
• hypoglycemia
• ketoacidosis
• head injury
• drug intoxication (for example, from analgesics, anticonvulsants, antihistamines, benzodiazepines, digoxin, ethanol (see ethanol overdose), heavy metals, hydrocarbons, barbiturates, insulin, lithium, organophosphates, phencyclidine, phenothiazines-oral, salicylates - oral, or tricyclic antidepressants)
• electrolyte abnormality (hypernatremia, hypercalcemia)
• infection

In the event of a seizure (in someone else), loosen clothing, lay the person flat, and protect the person from injury by moving furniture and other objects out of the area. Although frightening, seizures are rarely harmful.

For decreased consciousness caused by seizures (epilepsy), carry a Medic-Alert bracelet or pendant stating that you have a seizure disorder (in case you have a seizure in the future). Avoid any circumstance that has previously triggered a seizure.

For decreased consciousness due to a known medical condition or for unexplained decrease in consciousness consult your physician.
Follow prescribed treatment.

• unexplained, decreased consciousness occurs or is observed in someone else. Call 911 (or your local emergency number) if normal consciousness does not return quickly.

The medical history will be obtained and a physical examination performed. The physical examination will include a detailed examination of the cardiovascular and nervous system.

Medical history questions documenting decreased consciousness in detail may include:

• time pattern
  • When did it occur?
  • How long did the episode last?
  • Has it ever happened before?
    • How often?
    • Did the person behave the same way on previous episodes?
• associated conditions
  • Does the person have known epilepsy or seizure disorder?
  • Does the person have diabetes mellitus?
  • 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 also present?

Diagnostic tests that may be performed include:

• blood studies (such as CBC or blood differential measurement of electrolytes)
• CT scan or MRI of the head
• ECG
• EEG
• X-rays of the chest
• urinalysis

For seizure disorders, medications may be ordered. Surgery may be required to remove any tumor, scar, or abscess if one is causing epilepsy. Psychotherapy or counseling to understand and live with a seizure disorder may be recommended.