A infant on top feeding develops distension of abdomen & bleeding per rectum. He recently recovered from acute upper respiratory tract infection. What is probable diagnosis:
**Core Concept**
Intussusception is a medical emergency characterized by the invagination of one segment of the intestine into another, leading to intestinal obstruction and potentially severe complications such as ischemia, necrosis, and perforation. This condition typically presents with abdominal distension, vomiting, and bloody stools.
**Why the Correct Answer is Right**
The likely mechanism in this infant is that the acute upper respiratory tract infection led to a viral gastroenteritis, which caused the intestines to become inflamed and edematous. This, in turn, led to the telescoping of the ileum into the adjacent colon, resulting in intussusception. The bloody stools are a result of the mucosa being pinched off, leading to ischemia and ulceration. The abdominal distension is due to the obstruction caused by the intussusception.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not take into account the recent history of acute upper respiratory tract infection and its potential link to a viral gastroenteritis.
**Option B:** This option is incorrect because it is a rare cause of intussusception and would not typically present with a history of acute upper respiratory tract infection.
**Option C:** This option is incorrect because it is a condition that typically presents in older children and adults, and would not typically be associated with a recent history of acute upper respiratory tract infection.
**Clinical Pearl / High-Yield Fact**
Intussusception is a classic example of a "lead point" lesion, where a pathologic process such as a polyp or tumor causes the invagination of the intestine.
**Correct Answer:** C. Intussusception