Vomiting causing hypokalaemia

Causes vomiting via a number of different pathways

 

Hypovolaemia

Vomiting triggers the release of aldosterone to try and increase the blood pressure. Aldosterone enhances the reabsorption of sodium and water in the kidneys at the expense of potassium excretion.

Metabolic Alkalosis

Vomiting leads to the loss of acid - leading to alkalosis. Metabolic alkalosis prompts the kidneys to excrete bicarbonate to restore acid-base balance. As kidneys excrete bicarbonate potassium is also excreted.

Gastric Fluid

Gastric fluid itself contains a little potassium which would contribute to the hypokalaemia