A 9-month-old infant is brought to the emergency department by parents who report sudden onset of severe abdominal pain with intermittent crying episodes. Which assessment finding would be most characteristic of intussusception?

Intussusception is characterized by intermittent severe pain, currant jelly-like stools, and a sausage-shaped mass. The infant often draws knees to the chest during pain episodes. Other options are more typical of pyloric stenosis (projectile vomiting), peritonitis (rigid abdomen), or obstruction (high-pitched bowel sounds).

Understanding the Clinical Presentation of Intussusception

The classic triad of intussusception consists of intermittent severe abdominal pain, a palpable abdominal mass, and the passage of currant jelly-like stools. However, this complete triad is not always present, especially in the early stages. The condition occurs when a proximal segment of the intestine (the intussusceptum) telescopes into a distal segment (the intussuscipiens), leading to compromised venous return, bowel wall edema, and ultimately arterial obstruction. If left untreated, this progression results in mucosal ischemia, sloughing of tissue, and the classic dark, mucoid, blood-tinged stools [1].

Analysis of the Answer Choices

The correct answer is 3, as it captures two hallmark features of intussusception: the characteristic stool appearance and a specific pain response behavior.

* Option 1 (Projectile vomiting and visible peristaltic waves) is more characteristic of hypertrophic pyloric stenosis. In that condition, a non-bilious, projectile vomiting occurs typically in an infant aged 2 to 8 weeks, and visible gastric peristaltic waves may be seen moving from left to right across the epigastrium after feeding. This is a different pathophysiologic process involving a muscular, not telescoping, obstruction.

Option 2 (Rigid abdomen with rebound tenderness) indicates peritonitis, a late and serious complication. While intussusception can progress to peritonitis if bowel ischemia leads to perforation, this is not the most characteristic* initial finding. The presence of a rigid, tender abdomen with rebound tenderness suggests a surgical emergency from a perforated viscus or advanced strangulation, which represents a complication rather than the classic presentation of the condition itself [1].

* Option 3 (Currant jelly-like stools and drawing knees to chest) is the hallmark presentation. The "currant jelly" stool is a mixture of blood and mucus resulting from venous congestion and mucosal ischemia within the telescoped bowel segment [1, 3]. The intermittent, severe, crampy abdominal pain causes the infant to draw their knees up to the chest during episodes of colic. Between episodes, the infant may appear relatively normal or lethargic. This pattern of pain and the characteristic stool are highly specific for intussusception.

* Option 4 (High-pitched bowel sounds and abdominal distention) are general signs of a mechanical bowel obstruction. While intussusception is a cause of intestinal obstruction, these findings are not specific to it. They can be present in other conditions such as malrotation with volvulus or postoperative adhesions. The hallmark features in option 3 provide a more definitive clinical picture for intussusception.

Clinical Reasoning and Diagnostic Confirmation

When an infant presents with paroxysmal abdominal pain and drawing up of the legs, the nurse’s index of suspicion for intussusception should be high. The passage of a currant jelly-like stool is a late finding signifying mucosal necrosis, so its absence does not rule out the diagnosis. Early recognition is critical because non-operative management with ultrasound-guided hydrostatic or pneumatic reduction is highly effective and less invasive when performed promptly [2, 3]. Delays in diagnosis increase the risk of reduction failure, the need for surgical intervention, and the potential for bowel resection due to irreversible ischemia [2, 4]. The assessment finding of an infant drawing knees to the chest during pain episodes, coupled with a history or observation of currant jelly stools, should immediately prompt the nurse to prepare for diagnostic imaging, typically an abdominal ultrasound, which is the first-line diagnostic tool for confirming the "target sign" or "pseudokidney sign" of an intussusception [1].