alkalosis

Alkalosis refers to a condition reducing hydrogen ion concentration of arterial blood plasma (alkalemia). Generally alkalosis is said to occur when pH of the blood exceeds 7.45. The opposite condition is acidosis.

Types

More specifically, alkalosis can refer to:

• Respiratory alkalosis
• Metabolic alkalosis

Causes

The main cause of respiratory alkalosis is 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,^{[citation needed]} both of which would lower blood pH.

Metabolic alkalosis can be caused by prolonged 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 vice versa, a delicate balance is created between these two conditions.

Complications

Metabolic alkalosis is usually accompanied with hypokalemia, causing e.g. muscular weakness, myalgia, and muscle cramps (owing to disturbed function of the skeletal muscles), and constipation (from disturbed function of smooth muscles).

It may also cause hypocalcemia. As the pH of blood increases, the protein in the blood becomes more ionised into anions. This causes the free calcium present in blood to bind strongly with protein. If severe, it may cause tetany (alkalotic tetany).

See also

• Acidosis
• Acid-base physiology
• Acid-base homeostasis
• milk-alkali syndrome
• Mixed disorder of acid-base balance

References

• International Union of Pure and Applied Chemistry. "alkalosis". Compendium of Chemical Terminology Internet edition.

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