Clinical Chemistry: Acidosis and Alkalosis

Clinical chemistry is a field in pathology concerned with the analysis of bodily fluids. During analysis of bodily fluids, a pathologist may find that a person is suffering from alkalosis (too much alkali, or base, in the bloodstream) or acidosis (too much acid in the bloodstream). Alkalosis and acidosis cause an imbalance in the bloodstream's acid-base ratio and can be life threatening if not treated.

Facts

• Blood pH has to stay within the range of 7.35 to 7.45 so that the body's metabolic processes and the delivery of oxygen to tissues function appropriately. The measurement of alkalinity or acidity in a compound is the solution's pH level. The pH scale ranges from 0 to 14. A value below seven means the solution is acidic and a value above seven means the solution is basic. A value of exactly seven indicates a solution that is neutral or equally acidic and basic--or basically water. Acidosis is an excess of acid in the blood, which causes the blood's pH to fall under 7.35. Alkalosis is an excess of alkali (base) in the blood, which causes the blood's pH to rise above 7.45.

Types

• There are two categories to acid-base disorders. Respiratory alkalosis/acidosis affects respiration and causes changes in the body's carbon dioxide concentration. Metabolic alkalosis/acidosis affects the body's concentration of bicarbonate. Lung diseases or conditions affecting normal breathing are the most common cause for respiratory imbalances, whereas metabolic disorder causes include kidney disease, severe vomiting and diseases affecting normal metabolism.

Structure

• The lungs and kidneys are the major organs involved in regulating the blood's pH level. The body's metabolism produces primarily carbonic acid (created from carbon dioxide and water), along with smaller quantities of lactic acid, ketoacids and other organic acids. Lungs dispel acid out of the body through the process of breathing. Whenever you breathe, you exhale carbon dioxide. Kidneys expel acids through urine. In addition, they regulate the bicarbonate (a base) in the bloodstream. Both the lungs and kidneys work around the clock to expel the acids and regulate the alkalis that the body generates.

Diagnosis

• Doctors use blood gas and electrolytes to diagnose alkalosis and acidosis. Blood gas is a group of tests that provide a snapshot of the blood's levels of oxygen and carbon dioxide along with the blood's pH. These results allow the calculation of the amount of bicarbonate present in the bloodstream. Electrolytes are four tests: sodium (Na+), potassium (K+), chloride (Cl-) and bicarbonate. The amount of these electrolytes present in the bloodstream can indicate either acidosis or alkalosis.

Treatment

• For both alkalosis and acidosis, the first course of treatment is always to neutralize the acid or base in the blood. Once the blood pH is normalized, the underlying cause is treated. If the underlying cause is lung disease, treatment can include bronchodilators to reverse airway obstruction, and oxygen if blood oxygen levels are low.