A previously healthy infant presents with a recurrent episode of abdominal pain. The mother says that the child has been passing an altered stool after episodes of pain, but gives no history of vomiting or bleeding per diagnosis -rectum. Which of the following is the most likely diagnosis –
The infant in question has:


Recurrent episodes of abdominal pain
Passing of altered stools after episodes of pain
No vomiting or bleeding per rectum.


Most common presentation of rectal polyps and Meckel's diverticulum is painless rectal bleeding (option a & c are ruled out)
Necrotizing enterocolitis is seen in premature infants and is manifested in neonatal period. Symptoms progress from abdominal distension, vomiting, lethargy, poor feeding to passage of grossly bloody stool and features of shock (option d is excluded)
Now we are left with intussusception. Most common presentation is recurrent abdominal pain (Paroxysmal clock pain offer severe).
The absence of history of bleeding per rectum is creating some confusion here.
However, the altered stool should raise the suspicion of intussusception because intussusception typically presents with "currant jelly- stool" (altered stool) representing a mixture of blood, mucus and stool.
So, amongst the given options, best answer is intussusception.
Rectal Polys
Intussuception
Meckel's Diverticulum
Necrotizing Enterocolitis