From the Guidelines
Yes, loose stools and vomiting can lead to metabolic alkalosis, primarily through the loss of acid from the stomach during vomiting and loss of potassium through diarrhea, as supported by the study 1. This condition occurs when the body loses excess acid, causing the blood pH to rise. The loss of hydrochloric acid from the stomach during vomiting decreases the acid content in the body, shifting the pH balance toward alkalinity. Additionally, persistent diarrhea can cause potassium depletion, which further promotes alkalosis as the kidneys retain hydrogen ions and excrete more bicarbonate to compensate.
Key Mechanisms
- Loss of acid from the stomach during vomiting
- Loss of potassium through diarrhea
Clinical Presentation
Signs of metabolic alkalosis include:
- Confusion
- Muscle twitching
- In severe cases, tetany or seizures
Treatment
Treatment focuses on addressing the underlying cause of vomiting and diarrhea, while also correcting fluid and electrolyte imbalances through oral rehydration solutions containing appropriate amounts of sodium, potassium, and chloride, as recommended by the study 1. In severe cases, intravenous fluid replacement with normal saline may be necessary to restore proper acid-base balance. The study 1 also recommends the use of oral rehydration solutions (ORS) as the first-line therapy for mild to moderate dehydration caused by diarrhea of all causes. It is essential to replace ongoing losses in stools from infants, children, and adults with ORS, until diarrhea and vomiting are resolved, as stated in the study 1. The use of isotonic intravenous fluids, such as lactated Ringer’s and normal saline solution, should be administered when there is severe dehydration, shock, or altered mental status and failure of ORS therapy, as recommended by the study 1.
Recommendations
- Replace ongoing losses in stools with ORS, until diarrhea and vomiting are resolved
- Use isotonic intravenous fluids in severe cases
- Correct fluid and electrolyte imbalances through oral rehydration solutions containing appropriate amounts of sodium, potassium, and chloride.
From the Research
Metabolic Alkalosis Causes
- Metabolic alkalosis can be caused by the loss of fixed acid or a net accumulation of bicarbonate within the extracellular fluid 2
- The loss of acid may be via the gastrointestinal tract, such as vomiting, or the kidney 2
- Excessive hydrogen ion loss by the gastrointestinal tract, such as vomiting, can generate metabolic alkalosis 3
- Loose stools can also lead to the loss of fixed acid and contribute to metabolic alkalosis, although it is not explicitly mentioned in the provided studies, vomiting is a similar condition that can cause metabolic alkalosis
Metabolic Alkalosis Maintenance
- Maintenance of metabolic alkalosis reflects the inability of the kidney to excrete the excess of bicarbonate because of hypovolemia, chloride depletion, hypokalemia, hyperaldosteronism, renal failure, or a combination of these factors 3
- Factors that interfere with the kidney's mechanisms to eliminate excess bicarbonate, such as volume contraction, low glomerular filtration rate, potassium deficiency, hypochloremia, aldosterone excess, and elevated arterial carbon dioxide, can promote the generation or impair the correction of metabolic alkalosis 2
Clinical Presentation and Treatment
- Metabolic alkalosis is characterized by the primary elevation of serum bicarbonate and arterial pH, along with a compensatory increase in Pco2 consequent to adaptive hypoventilation 2
- The cornerstone of treatment is the correction of existing depletions and the prevention of further losses 3
- In vomiting-induced chloride depletion alkalosis, infusion of potassium chloride restores the excretion of bicarbonate by the kidney 3