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Metabolic alkalosis: Difference between revisions
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{{Infobox medical condition | <section begin="clinical biochemistry" />{{Infobox medical condition | ||
| name = Metabolic alkalosis | | name = Metabolic alkalosis | ||
| definition = A process increasing pH due to metabolic process | | definition = A process increasing pH due to metabolic process | ||
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=== Contraction alkalosis === | === Contraction alkalosis === | ||
Loss of fluid which is rich in sodium chloride but low in bicarbonate concentration may cause a form of metabolic alkalosis called contraction alkalosis. The bicarconate concentration increases not because of increased bicarbonate but because of decreased bicarbonate-poor volume (concentration = solute/volume). Contraction alkalosis is usually not significant to cause alkalaemia alone and is therefore usually one etiology of multiple. | Loss of fluid which is rich in sodium chloride but low in bicarbonate concentration may cause a form of metabolic alkalosis called contraction alkalosis. The bicarconate concentration increases not because of increased bicarbonate but because of decreased bicarbonate-poor volume (concentration = solute/volume). Contraction alkalosis is usually not significant to cause alkalaemia alone and is therefore usually one etiology of multiple. | ||
<section end="clinical biochemistry" /> | |||
=== Bartter syndrome and Gitelman syndrome === | === Bartter syndrome and Gitelman syndrome === | ||
Bartter syndrome is a disorder of the renal tubule (tubulopathy) and a genetic disorder where the Na-K-2Cl cotransporter in the thick ascending loop is impaired. This is the same cotransporter that loop diuretics inhibits, so Bartter syndrome mimics chronic loop diuretic treatment. | Bartter syndrome is a disorder of the renal tubule (tubulopathy) and a genetic disorder where the Na-K-2Cl cotransporter in the thick ascending loop is impaired. This is the same cotransporter that loop diuretics inhibits, so Bartter syndrome mimics chronic loop diuretic treatment. | ||
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Both syndromes cause hypokalaemia, metabolic alkalosis, and a reduction in plasma volume. As a result, there is increased activity of [[RAAS]] with [[secondary hyperaldosteronism]]. | Both syndromes cause hypokalaemia, metabolic alkalosis, and a reduction in plasma volume. As a result, there is increased activity of [[RAAS]] with [[secondary hyperaldosteronism]]. | ||
<section begin="clinical biochemistry" /> | |||
== Types == | == Types == | ||
One may distinguish between two types of metabolic alkalosis depending on whether administration of chloride is effective in the treatment. Chloride-responsive metabolic alkalosis occurs due to vomiting, contraction alkalosis, and diuretics. Chloride-resistant metabolic alkalosis occurs due to hypokalaemia, hyperaldosteronism, Bartter syndrome, and Gitelman syndrome. | One may distinguish between two types of metabolic alkalosis depending on whether administration of chloride is effective in the treatment. Chloride-responsive metabolic alkalosis occurs due to vomiting, contraction alkalosis, and diuretics. Chloride-resistant metabolic alkalosis occurs due to hypokalaemia, hyperaldosteronism, Bartter syndrome, and Gitelman syndrome. | ||
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The cause of metabolic alkalosis is often apparent by the anamnesis. If not, rare causes like hyperaldosteronism and genetic syndromes should be sought. Measurement of urine chloride may be helpful to narrow down the causes. Chloride-responsive metabolic alkalosis has a urine chloride concentration < 20 mmol/L, while chloride-resistant type has a concentration > 40 mmol/L. | The cause of metabolic alkalosis is often apparent by the anamnesis. If not, rare causes like hyperaldosteronism and genetic syndromes should be sought. Measurement of urine chloride may be helpful to narrow down the causes. Chloride-responsive metabolic alkalosis has a urine chloride concentration < 20 mmol/L, while chloride-resistant type has a concentration > 40 mmol/L. | ||
<section end="clinical biochemistry" /> | |||
== Management == | == Management == | ||
As metabolic alkalosis is not a disease of itself but rather a consequence, the underlying disease must be identified and treated. This will reverse the metabolic alkalosis. | As metabolic alkalosis is not a disease of itself but rather a consequence, the underlying disease must be identified and treated. This will reverse the metabolic alkalosis. | ||