Acidosis is excessive blood acidity caused by an overabundance of acid in the blood or a loss of bicarbonate from the blood (metabolic acidosis), or by a buildup of carbon dioxide in the blood that results from poor lung function or slow breathing (respiratory acidosis).
• Blood acidity increases when people ingest substances that contain or produce acid or when the lungs do not expel enough carbon dioxide.
• People with metabolic acidosis have nausea, vomiting, and fatigue and may breathe faster and deeper than normal.
• People with respiratory acidosis have headache and confusion, and breathing may appear shallow, slow or both.
• Tests on blood samples show there is too much acid.
• Doctors treat the cause of the acidosis.
If an increase in acid overwhelms the body's pH buffering systems, the blood will become acidic. As blood pH drops, the parts of the brain that regulate breathing are stimulated to produce faster and deeper breathing. Breathing faster and deeper increases the amount of carbon dioxide exhaled.
The kidneys also try to compensate by excreting more acid in the urine. However, both mechanisms can be overwhelmed if the body continues to produce too much acid, leading to severe acidosis and eventually coma.
Major Causes of Respiratory Acidosis and Alkalosis
Respiratory acidosis develops when the lungs do not expel carbon dioxide adequately, a problem that can occur in diseases that severely affect the lungs (such as emphysema, chronic bronchitis, severe pneumonia, pulmonary edema, and asthma). Respiratory acidosis can also develop when diseases of the brain or of the nerves or muscles of the chest impair breathing. In addition, people can develop respiratory acidosis when their breathing is slowed due to over sedation from opioids (narcotics) or strong drugs that induce sleep (sedatives).
• Lung disorders, such as emphysema, chronic bronchitis, severe asthma, pneumonia, or pulmonary edema
• Sleep-disordered breathing
• Diseases of the nerves or muscles of the chest that impair breathing, such as Guillain-Barré syndrome or amyotrophic lateral sclerosis
• Overdose of drugs such as alcohol, opioids, and strong sedatives
Respiratory alkalosis
• Anxiety
• Aspirin
• Fever
• Low levels of oxygen in the blood
• Pain
Symptoms
People with mild metabolic acidosis may have no symptoms but usually experience nausea, vomiting, and fatigue. Breathing becomes deeper and slightly faster (as the body tries to correct the acidosis by expelling more carbon dioxide). As the acidosis worsens, people begin to feel extremely weak and drowsy and may feel confused and increasingly nauseated. Eventually, blood pressure can fall, leading to shock, coma, and death.
The first symptoms of respiratory acidosis may be headache and drowsiness. Drowsiness may progress to stupor and coma. Stupor and coma can develop within moments if breathing stops or is severely impaired, or over hours if breathing is less dramatically impaired.
Diagnosis : The diagnosis of acidosis generally requires the measurement of blood pH in a sample of arterial blood, usually taken from the radial artery in the wrist. Arterial blood is used because venous blood contains high levels of bicarbonate and thus is generally not as accurate a measure of the body's pH status.
To learn more about the cause of the acidosis, doctors also measure the levels of carbon dioxide and bicarbonate in the blood. Additional blood tests may be done to help determine the cause.
Acidosis may also be treated directly. If the acidosis is mild, the administration of intravenous fluids may be all that is needed. Rarely, when acidosis is very severe, bicarbonate may be given intravenously. However, bicarbonate provides only temporary relief and may cause harm—for instance, by overloading the body with sodium and water.
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