Temporary Confusion or Decreased Alertness

Many health problems cause confusion or decreased alertness. It is not unusual for a person who is sick to be sleepy or confused when he or she wakes up. But extreme sleepiness may be a symptom of a more serious health problem.

Confusion may range from mild to severe. Symptoms of confusion may include:

• Jumbled or disorganized thoughts.
• Unusual, bizarre, or aggressive behavior.
• Having trouble solving problems or doing tasks that used to be easy for you.
• Not knowing where you are or not recognizing family members or familiar items.
• Firmly held but false beliefs (Reference delusions Opens New Window).
• Seeing, hearing, feeling, smelling, or tasting things that are not really there (Reference hallucinations Opens New Window or illusions).
• Unfounded suspicions that others are after you or want to harm you (paranoia).

Decreased alertness occurs when a person is not fully awake, aware of, or able to respond normally to his or her external environment. Decreased alertness may also mean that a chronic illness has gotten worse.

A sudden change in the mental state or level of consciousness may be caused by:

• A head injury. Serious head injuries may cause injuries to the brain.
• Decreased or blocked blood flow to the brain. This may occur during a Reference transient ischemic attack (TIA) Opens New Window or a Reference stroke Opens New Window.
• A seizure disorder (Reference epilepsy Opens New Window).
• A disease, such as a brain tumor or problems from Reference diabetes Opens New Window.
• Environmental factors, such as Reference dehydration Opens New Window, cold temperature exposure (hypothermia), and heatstroke.
• Medicines and alcohol or drug abuse or withdrawal.
• Infection, especially an infection of the nervous system.
• Shock that is caused by infection that has spread throughout the blood and tissues (Reference sepsis).
• Heart problems, such as a Reference heart attack Opens New Window, an irregular heart rhythm (Reference arrhythmia Opens New Window), or Reference heart failure Opens New Window.
• Thyroid problems, such as Reference hyperthyroidism Opens New Window.
• Low oxygen levels from Reference chronic obstructive pulmonary disease (COPD) Opens New Window, Reference pulmonary embolism (PE) Opens New Window, or altitude sickness.
• Reference Metabolism Opens New Window problems from liver or kidney failure.

Other problems that may lead to confusion or decreased alertness include:

• Decreased hearing or vision.
• Reference Electrolyte imbalances Opens New Window, such as low levels of sodium and potassium in the blood.
• Low blood sugar (Reference hypoglycemia Opens New Window) or high blood sugar (hyperglycemia).
• Malnutrition and vitamin deficiencies.
• Sleep problems, such as the inability to fall asleep or stay asleep (Reference insomnia Opens New Window) or Reference sleep apnea Opens New Window.

A complete medical examination may be needed before the cause of your confusion or decreased alertness can be diagnosed. Treatment depends on the cause of the problem. Contact your doctor for an exam if you are having problems with confusion or decreased alertness.

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This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Reference Terms of Use. Reference How this information was developed to help you make better health decisions.