Respiratory Alkalosis

What is this Condition?

Respiratory alkalosis is a condition marked by a decrease in the partial pressure of carbon dioxide of less than 35 millimeters of mercury, which is due to alveolar hyperventilation. Uncomplicated respiratory alkalosis leads to a decrease in hydrogen ion concentration, which causes elevated blood pH. Hypocapnia (decreased carbon dioxide in the blood) occurs when the elimination of carbon dioxide by the lungs exceeds the production of carbon dioxide in the cells.

What Causes it?

Causes of respiratory alkalosis fall into two categories:

o pulmonary: pneumonia, interstitial lung disease, pulmonary blood vessel disease, and acute asthma

o nonpulmonary: anxiety, fever, aspirin toxicity, metabolic acidosis, central nervous system disease (inflammation or tumor), sepsis, liver failure, and pregnancy.

What are its Symptoms?

The cardinal sign of respiratory alkalosis is deep, rapid breathing, possibly more than 40 breaths per minute. This hyperventilation usually leads to light-headedness or dizziness, agitation, numbness and tingling around the mouth, wrist and foot spasms, twitching, and weakness. Severe respiratory alkalosis may cause irregular heart­beats, seizures, or both.

How is it Diagnosed?

This condition is diagnosed by arterial blood gas analysis, which measures the level of oxygen, carbon dioxide, and other gases in the blood.

How is it Treated?

Treatment is designed to eradicate the underlying condition, for example, removal of ingested toxins, treatment of fever, and treatment of central nervous system disease. In severe respiratory alkalosis, the person may be instructed to breathe into a paper bag, which helps relieve acute anxiety and increases carbon dioxide levels.

How is it diagnosed?

Typical clinical features with appropriate lab data and X-ray findings suggest sarcoidosis. A positive Kveim-Siltzbach skin test supports the diagnosis. In this test, the person receives an injection of an antigen prepared from spleen or lymph node tissue from people with sarcoidosis. If the person has active sarcoidosis, granuloma develops at the injection site in 2 to 6 weeks. This reaction is considered positive when removal and analysis of skin tissue at the injection site shows discrete epithelioid cell granuloma.

Other relevant diagnostic tests include:

o chest X-ray

o removal and analysis of lymph node, skin, or lung tissue

o pulmonary function tests

o blood tests and arterial blood gas studies.

A negative tuberculin skin test, fungal serologies, and sputum cultures for mycobacteria and fungi, as well as negative biopsy cultures, help rule out infection.