What is a classic sign of intussusception in a child?

A classic sign of intussusception in a child is "currant jelly" stool. This distinctive type of stool results from the mixing of blood and mucus that occurs when part of the intestine telescopes into itself, leading to ischemia and subsequent bleeding. The appearance of the stool resembles jelly, often described as dark red or maroon in color, which serves as an important diagnostic clue for healthcare providers when evaluating a child presenting with abdominal pain and other gastrointestinal symptoms.

Severe abdominal pain is frequently seen in cases of intussusception, but it is more of a symptom rather than a unique sign that specifically points to this condition. While yellow-green vomiting can occur in various gastrointestinal issues, it is not exclusive to intussusception and can be seen in other conditions as well. Diarrhea is also a common symptom in many pediatric gastrointestinal disorders and does not specifically indicate intussusception. Thus, the presence of "currant jelly" stool is a hallmark feature that assists in identifying this particular medical emergency.