Respiratory Alkalosis

Alternate Names
hyperventilation-induced alkalosis

Definition of Respiratory Alkalosis

Alkalosis describes an imbalance of chemistry in the body in which the amount of alkali (base) in the body fluids and cells compared to the amount of acid is increased..It may be due to breathing too fast, which is called respiratory alkalosis.

What is going on in the body?

The kidneys and lungs work together to keep the level of acid and base in the body in a delicate balance. The kidneys can get rid of acid in the urine and the lungs can get rid of acid in the form of carbon dioxide gas. Many different conditions can cause the lungs to breathe out more carbon dioxide than usual.

What are the signs and symptoms of the condition?

An individual with respiratory alkalosis breathes harder and faster than normal. If a person is breathing fast to get rid of extra acid in the body, this is usually the only symptom. If the level of acid is normal in the body, respiratory alkalosis may cause:

• light-headedness or dizziness
• numbness or tingling, especially in the hands, feet, and mouth
• uncontrollable muscle spasms, which only occur in severe cases

The underlying cause may also result in symptoms.

What are the causes and risks of the condition?

There are many things that can cause an abnormal buildup of acids in the body. Examples include dehydration, infection, not getting enough oxygen, certain toxins, and kidney problems. Respiratory alkalosis in these cases is called a "compensating" respiratory alkalosis because it is a normal reaction to bring the body's acid-base balance back to normal or near normal.

Cases in which the balance is abnormally shifted to the "base" or alkali side of normal may be caused by:

• anxiety
• brain damage, such as head injury or a stroke
• certain medications, such as aspirin
• pregnancy, which usually causes only mild cases
• liver failure, such as cirrhosis
• inflammation or tumors in the central nervous system

What can be done to prevent the condition?

Anxiety is one of the more common causes of abnormal fast breathing. It can be treated with psychotherapy and medication to prevent a person from hyperventilating. Aspirin and other medications should be taken only as directed.

Another cause of respiratory alkalosis is exposure to high altitudes. At higher altitudes, the low pressure causes a person to have to breathe faster to get enough oxygen, but he or she "blows off" carbon dioxide at a faster rate than usual in the process, resulting in respiratory alkalosis. The symptoms of fast breathing can be prevented with medications taken before a climb. Climbing slowly can also prevent symptoms, as it gives the body time to adjust.

How is the condition diagnosed?

The condition may be suspected from the history and examination. The diagnosis is made by an arterial blood gas test. This test measures the balance of acid and base in the blood and determines if the cause of the imbalance is breathing too fast.

What are the long-term effects of the condition?

There are generally no long-term effects to respiratory alkalosis. The underlying cause of the condition may, however, have quite serious effects. For example, the underlying cause may be brain damage.

What are the risks to others?

There are no risks to others, as this condition is not contagious.

What are the treatments for the condition?

In a compensating respiratory alkalosis, the cause of the extra acid load in the body needs to be treated. If the condition is caused by anxiety, the person can try putting a paper bag over his or her mouth. By rebreathing the air in the paper bag, the person may be able to stop the attack of fast breathing. Sedatives may also be needed to calm the person.

What are the side effects of the treatments?

Sedatives can cause drowsiness, allergic reactions, and other side effects, depending on the medication used.

What happens after treatment for the condition?

The person's life after treatment depends on the underlying cause. For example, if the underlying cause is brain damage, a person may need lifelong treatment. If the underlying cause can be fixed, no further treatment is needed.

How is the condition monitored?

Regular arterial blood gases may be used to monitor respiratory alkalosis. Any new or worsening symptoms should be reported to the healthcare professional.