Mechanism of metabolic alkalosis caused by pyloric obstruction

summary

* pyloric obstruction is the difficulty in passing pylorus, and the contents of stomach can not pass through, causing massive retention in the stomach. It is characterized by severe vomiting, which leads to malnutrition and electrolyte disturbance. The water electrolyte disorder caused by it is often dehydration, low potassium, low chlorine, metabolic alkalosis. The mechanism of its occurrence is mainly because the gastric juice is acidic and contains a large number of potassium ions and chloride ions. The loss of a large number of acids can lead to metabolic alkalosis. I will elaborate the specific mechanism of its occurrence in detail.

Mechanism of metabolic alkalosis caused by pyloric obstruction

First: the pyloric equivalent to the outlet of the stomach, corresponding to the cardia, is the narrowest part of the digestive tract, so prone to pyloric obstruction, the cause is mostly peptic ulcer, initially due to inflammatory stimulation caused by edema or smooth muscle contraction, repeated ulcer attack and healing can eventually lead to scar pyloric obstruction, this is irreversible.

Second, the body itself is weakly alkaline, pH is about 7.4, and its balance mainly depends on the acid-base balance. The occurrence of metabolic alkalosis is mainly excessive alkali or loss of acid. The mechanism of metabolic alkalosis caused by pyloric obstruction is mainly the latter, because the normal gastric juice is acidic, and its pH is about 2.0. In addition, gastric juice contains a lot of chloride ions, The loss of chloride ion can lead to compensatory alkali increase.

Third: * pyloric obstruction can lead to stomach contents passing through obstacles, and then a large amount of retention will eventually lead to severe vomiting. Such patients may have malnutrition due to difficulty in eating. Gastric juice contains a lot of water and electrolytes, the latter is mainly hydrogen ion, chloride ion and potassium ion. Frequent and severe vomiting can lead to the loss of these electrolytes, which can lead to dehydration, low potassium and low chloride alkalosis.

matters needing attention

If pyloric obstruction is temporary, that is, it is caused by edema or pyloric sphincter spasm, it can be relieved by gastrointestinal decompression and spasmolysis, but if it can not be relieved, it needs to consider scar pyloric obstruction, which is the absolute indication of operation, but the premise is to correct the patient's water electrolyte disorder.