Confusion is the inability to think with your usual speed or clarity. When confused, you have difficulty focusing your attention and may feel disoriented. Confusion interferes with your ability to make decisions.

Confusion may come on suddenly or gradually over time, depending on the cause. Some confused people may behave aggressively.

Many times, confusion is temporary. Other times it is permanent and not curable. Confusion is more common in the elderly, and often occurs during hospitalization.

Confusion may be caused by:

• Alcohol intoxication
• Low blood sugar
• Head trauma or head injury
• Concussion
• Fluid and electrolyte imbalance
• Nutritional deficiencies, particularly niacin , thiamine, Vitamin C, or Vitamin B-12
• Fever
• Sudden drop in body temperature (hypothermia)
• Low levels of oxygen (for example, from chronic lung disorders)
• Medications
• Infections
• Brain tumor
• Illness in an elderly person
• Sleep deprivation
• Seizures

A good way to test to see if a person is confused is to ask the person his or her name, age, and the date. If they are unsure or answer incorrectly, they are confused.

A confused person should not be left alone. To ensure a confused person's safety, physical restraints may be required in some situations. Try to keep the surroundings calm, quiet, and peaceful.

When visiting a person whose confusion is from a chronic disease, you should always introduce yourself each time you see them, no matter how well he or she once knew you. Placing a calendar and clock near the person can help keep him or her oriented. When taking care of someone who is confused, frequently remind the person of his or her location. Talk to him or her about current events and plans for the day.

For sudden confusion due to low blood sugar (for example, from diabetes medication), the person should drink a sweet drink or eat a sweet snack. If the confusion lasts longer than 10 minutes, call the doctor.

Call 911 if:

• Confusion has come on suddenly or is accompanied by other symptoms like headache, feeling dizzy or faint, rapid pulse, slow or rapid breathing, cold or clammy skin, uncontrolled shivering, or fever.
• Confusion has come on suddenly in someone with diabetes.
• Confusion came on following a head injury.
• The person becomes unconscious at any time.

If you have had ongoing confusion that came on gradually, call for an appointment with your doctor if you have never been evaluated for this problem.

The doctor will perform a physical examination and ask questions such as:

• Does the person get days and nights mixed up? Are they awake during their usual sleep time?
• Do they recognize people?
• Do they know where they are?
• Do they know the date and time?
• Can they answer questions appropriately?
• Is the person always confused?
• Are there repeated episodes?
• Is the confusion rapidly getting worse?
• Does the confusion come and go?
• Has there been any recent illness?
• Has there been a recent head injury?
• Is the person diabetic?
• Does the person have COPD, chronic bronchitis, or a similar lung disorder?
• What medications is the person taking?
• Has there been any exposure to other drugs or alcohol?

The physical examination will include a thorough evaluation of brain and nervous system function. Neurologic tests and cognitive tests may be performed. Tests such as an MRI of the head, blood and urine tests, and an EEG may be indicated, depending upon accompanying signs and symptoms.

• Obtain a regular amount of sleep
• Eat a balanced diet with plenty of vitamins and minerals.
• Don't drink alcohol in excess.
• Keep careful control of your blood sugar if you have diabetes.
• Quit smoking, which puts you at greater risk for lung diseases.

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Biem J. Out of the cold: management of hypothermia and frostbite. CMAJ. 2003; 168(3): 305-311.