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A Patient With Metabolic Alkalosis

So you think about metabolic alkalosis and there are actually 2 stages. There's the acute phase, also called the generation phase. For example, a person who has just started vomiting or who is undergoing nasogastric suctioning. The second stage is the maintenance phase where the kidneys, for some reason, are unable to get rid of the excessive bicarbonate...

So let us elaborate on this. If you take GI issues such as excessive vomiting or nasogastric suctioning or congenital chloride diarrhea and VIPomas, what happens over there is, there is a loss of hydrogen ions and chloride ions, of course. And of course, there is loss of volume. With the loss of hydrogen ions one can get alkalosis…

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 Alkalotics Anonymous: Severe Metabolic Alkalosis

The differential diagnosis for severe metabolic alkalosis can be divided into disorders that cause either acid loss or base gain. Acid loss can be a consequence of vomiting, diarrhea, diuretic use, or volume contraction. States of mineralocorticoid excess also result in impaired excretion of bicarbonate and net acidification of urine. Exogenous base gain can occur with use of absorbable antacids containing sodium bicarbonate or calcium carbonate or with administration of agents containing anion components that are metabolized to bicarbonate, such as citrate or acetate. While ingestion of calcium-based antacids, alone or with large amounts of dairy or milk, as in the now-defunct Sippy diet for treatment of ulcers, tends to produce hypercalcemia and alkalosis, sodium-based antacids produce alkalosis without hypercalcemia.

 Metabolic Alkalosis

HCO3 levels below 40 are usually asymptomatic. Levels above 50 can however cause a number of serious complications including severe hypoventilation, decreased cardiac contractility and output, arrhythmias and seizures. Another important concept to keep in mind is that metabolic alkalosis requires both of: 1) an initiation factor, and 2) a maintenance factor that prevents the kidney from correcting the imbalance by excreting excess HCO3.

Articles of Interest

Approach to metabolic alkalosis

Metabolic alkalosis is a common disorder, accounting for half of all acid-base disturbances in hospitalized patients. It is the result of an increase in bicarbonate production, a decrease in bicarbonate excretion, or a loss of hydrogen ions. Most causes of metabolic alkalosis can be divided into 4 categories: chloride depletion alkalosis, mineralocorticoid excess syndromes, apparent mineralocorticoid excess syndromes, and excess alkali administration. Treatment is usually supportive and based on cause of the alkalosis.

Chapter 14. Metabolic Alkalosis

The development of metabolic alkalosis is a two step process: generation and maintenance.

Diagnosis Of And Causes Of Metabolic Alkalosis

The management of metabolic alkalosis depends primarily on the underlying etiology and on the patient’s volume status. Direct treatment of the alkalosis itself (eg, administration of acidic intravenous solutions) may be indicated in some cases.

Management of metabolic alkalosis

A good article on metabolic alkalosis in ICU was published by Webster and Kulkarni in 1999. According to them, treatment of metabolic alkalosis consists of three essential components. Correct the aetiology of the bicarbonate retention (eg. the volume deficit), correct the source of chloride loss (be it diarrhoea or NG drainage) and correct co-existing electrolyte abnormalities (eg. potassium and magnesium).

Metabolic alkalosis

Most cases of metabolic alkalosis don't require specific therapy directed at immediately reducing the bicarbonate. Instead, resolving the underlying cause is generally sufficient.

Metabolic Alkalosis Part 1

In order for a patient to have a persistent metabolic alkalosis TWO ‘problems’ have to occur: first the patient has to develop a problem or condition that causes a metabolic alkalosis, and then a second problem that maintains the metabolic alkalosis. All the ‘problems’ are associated with significant electrolyte derangements. For that reason, many have suggested to think about metabolic alkalosis as mainly a disorder of electrolytes that is accompanied by an increase in the number of bicarbonate molecules and the pH of the extracellular fluid.

Metabolic Alkalosis Part 2

A chloride deficit is the most common maintaining process for human patients with a metabolic alkalosis, and this is probably true for veterinary patients also. Because electroneutrality has to be maintained in the body, chloride is lost with a cation, which means in most cases the patient will lose NaCl, KCl, or HCl. Similar to HCl deficit, KCl deficit results in gain of bicarbonate in the extracellular fluid compartment. Let’s consider a patient on furosemide (a loop diuretic that causes loss of potassium in the urine, and is one of the differentials for a hypochloremic metabolic alkalosis).

Pathophysiology, Evaluation, and Management of Metabolic Alkalosis

The pathogenesis of chronic metabolic alkalosis includes two derangements, generation of metabolic alkalosis via gain of alkali or loss of acid and maintenance of metabolic alkalosis by increased tubular HCO3− reabsorption (failure of the kidneys to excrete excess alkali). Metabolic alkalosis is the most common acid-base disorder in hospitalized patients, particularly in the surgical critical care unit. Mortality increases as pH increases.

Severe Metabolic Alkalosis from Acute Baking Soda Ingestion Presenting with Acute Respiratory Failure and Ischemic Stroke

Baking Soda (Sodium Bicarbonate) is a salt composed of sodium and bicarbonate ions. It is a widely available household product used for cooking, baking, personal care and cleaning purposes. It has long been used also as a home remedy for heartburn and indigestion, and also misused as an agent to “beat a urine drug test” and to treat urinary infections.

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Anesthesia Key

Metabolic acidosis gets all the headlines, but metabolic alkalosis is the most common acid-base disorder in hospitalized patients. The prevalence of metabolic alkalosis can be attributed to three factors: (a) common etiologies (e.g., diuretic therapy), (b) a tendency for the alkalosis to be sustained (thanks to chloride), and (c) failure to identify and correct the factors that maintain the alkalosis.

EMCrit Project

If the serum bicarbonate is elevated (>28 mM), this alone reveals a metabolic alkalosis.

Milk-Alkali Syndrome

Milk-alkali syndrome (MAS) consists of hypercalcemia, various degrees of renal failure, and metabolic alkalosis due to ingestion of large amounts of calcium and absorbable alkali. This syndrome was first identified after medical treatment of peptic ulcer disease with milk and alkali was widely adopted at the beginning of the 20th century. With the introduction of histamine2 blockers and proton pump inhibitors, the occurrence of MAS became rare; however, a resurgence of MAS has been witnessed because of the wide availability and increasing use of calcium carbonate, mostly for osteoporosis prevention.

Life in the Fastlane

Avoid hyperventilation as this worsens the alkalaemia