Features of pyloric stenosis
**Core Concept**
Pyloric stenosis refers to the narrowing of the pyloric channel, which is the passage that connects the stomach to the small intestine. This narrowing causes gastric outlet obstruction, leading to symptoms such as vomiting, abdominal distension, and weight loss in infants. The pathophysiology involves hypertrophy of the pyloric muscle and thickening of the pyloric mucosa, which impedes the normal flow of gastric contents into the small intestine.
**Why the Correct Answer is Right**
The correct answer is associated with the clinical presentation of pyloric stenosis. The key features include projectile vomiting, which is a characteristic symptom, and a palpable olive-shaped mass in the right upper quadrant of the abdomen. This mass is due to the hypertrophied pyloric muscle. Another important feature is the presence of gastric peristaltic waves, which are visible as a "tiger's roar" or "pulsion" of the abdominal wall. These waves are a result of the stomach's attempt to overcome the obstruction at the level of the pylorus.
**Why Each Wrong Option is Incorrect**
**Option A:**
- This option is incorrect because pyloric stenosis is not typically associated with a palpable gastric mass. The pyloric mass is usually felt in the right upper quadrant, not the epigastrium.
**Option B:**
- This option is incorrect because pyloric stenosis is not typically associated with acute abdominal pain. While infants with pyloric stenosis may have some discomfort, the classic presentation is more insidious, with symptoms developing over several weeks.
**Option C:**
- This option is incorrect because pyloric stenosis is not typically associated with a palpable liver or spleen. The liver and spleen are not directly involved in the pathophysiology of pyloric stenosis.
**Option D:**
- This option is incorrect because pyloric stenosis is not typically associated with a palpable kidney mass. The kidneys are not directly involved in the pathophysiology of pyloric stenosis.
**Clinical Pearl / High-Yield Fact**
A key clinical feature to remember is the presence of gastric peristaltic waves, which are a result of the stomach's attempt to overcome the obstruction at the level of the pylorus. These waves can be visible as a "tiger's roar" or "pulsion" of the abdominal wall.
**Correct Answer:**
(Insert the correct letter from the options provided)