|Classification and external resources|
Alkalosis refers to a condition reducing hydrogen ion concentration of arterial blood plasma (alkalemia). In contrast to acidosis (serum pH 7.35 or lower), alkalosis occurs when the serum pH is higher than normal (7.45 or higher). Alkalosis is usually divided into the categories of respiratory alkalosis and metabolic alkalosis or a combined alkolosis.
Respiratory alkolosis is caused by hyperventilation, resulting in a loss of carbon dioxide. Compensatory mechanisms for this would include increased dissociation of the carbonic acid buffering intermediate into hydrogen ions, and the related excretion of bicarbonate, both of which lower blood pH. Hyperventilation-induced alkalosis can be seen in several deadly central nervous system diseases such as strokes, certain cancers, or Rett syndrome.
Metabolic alkalosis can be caused by repeated vomiting, resulting in a loss of hydrochloric acid with the stomach content. Severe dehydration, and the consumption of alkali are other causes. It can also be caused by administration of diuretics and endocrine disorders such as Cushing's syndrome. Compensatory mechanism for metabolic alkalosis involve slowed breathing by the lungs to increase serum carbon dioxide, a condition leaning toward respiratory acidosis. As respiratory acidosis often accompanies the compensation for metabolic alkalosis, and viceversa, a delicate balance is created between these two conditions.
Signs and symptoms
Metabolic alkalosis is usually accompanied with low blood potassium level, causing, e.g., muscular weakness, muscle pain, and muscle cramps (from disturbed function of the skeletal muscles), and muscle spasms (from disturbed function of smooth muscles).
It may also cause low blood calcium levels. As the blood pH increases, blood transport proteins, such as albumin, become more ionized into anions. This causes the free calcium present in blood to bind more strongly with albumin. If severe, it may cause tetany.
- Acid-base physiology
- Acid-base homeostasis
- milk-alkali syndrome
- Mixed disorder of acid-base balance
- IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "alkalosis".