True about pyloric stenosisa) Hypokalemiab) Hyponatremiac) Metabolic acidosisd) Hypochloremiae) Hypocalcemia
**Core Concept**
Pyloric stenosis is a clinical condition characterized by the narrowing of the pyloric canal, leading to gastric outlet obstruction. This obstruction results in the accumulation of gastric contents in the stomach, which in turn causes a series of metabolic disturbances.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of pyloric stenosis. The obstruction of the pyloric canal leads to vomiting, which is characterized by the loss of gastric contents rich in hydrochloric acid (HCl). The loss of HCl results in a decrease in chloride ions (Cl-) in the body, which is known as hypochloremia. This metabolic disturbance is a hallmark of pyloric stenosis.
**Why Each Wrong Option is Incorrect**
* **Option A:** Hypokalemia is a result of potassium loss due to vomiting, but it is not the most direct consequence of pyloric stenosis. While hypokalemia can occur, it is not as specific to the condition as hypochloremia.
* **Option B:** Hyponatremia can occur due to the loss of sodium ions in the vomited gastric contents, but it is not as directly related to pyloric stenosis as hypochloremia.
* **Option C:** Metabolic acidosis can occur in pyloric stenosis due to the loss of bicarbonate ions in the vomited gastric contents, but it is not as specific a consequence of the condition as hypochloremia.
* **Option E:** Hypocalcemia is not a direct consequence of pyloric stenosis. While electrolyte imbalances can occur, hypocalcemia is not as specifically related to the condition as hypochloremia.
**Clinical Pearl / High-Yield Fact**
Pyloric stenosis is a classic cause of hypochloremic metabolic alkalosis, which is characterized by a decrease in chloride ions and an increase in bicarbonate ions in the blood. This condition is often associated with vomiting and can be a life-threatening emergency if left untreated.
**Correct Answer:** D. Hypochloremia