What is the most important step in managing a 15-month-old infant with abdominal discomfort, emesis, bloody mucous per rectum, and an obstructive pattern on abdominal film?

Management of Suspected Intussusception in a 15-Month-Old Infant

The most important step in managing this 15-month-old infant is barium enema (or air/hydrostatic enema), as this clinical presentation is classic for intussusception, and enema reduction is both diagnostic and therapeutic, potentially avoiding surgery and its associated morbidity. 1

Clinical Reasoning

This infant presents with the classic triad of intussusception:

• Abdominal discomfort with apparent colicky pain 2
• Vomiting 2
• Bloody mucous per rectum ("currant jelly" stools) 3
• Age-appropriate presentation (peak incidence 3 months to 3 years, most common at 5-9 months, but certainly occurs at 15 months) 2
• Obstructive pattern on abdominal film consistent with intestinal obstruction 2

The American College of Radiology specifically notes that intussusception "may be diagnosed clinically by crampy, intermittent abdominal pain sometimes progressing to bloody stools and lethargy" 2. While intussusception is "unusual in the first 3 months of life," it is the most common cause of intestinal obstruction in young children beyond this age 2, 1.

Why Enema Reduction is the Priority

Enema reduction (pneumatic or hydrostatic) serves dual purposes:

• Diagnostic confirmation of intussusception 1
• Therapeutic reduction that can resolve the obstruction non-operatively, avoiding surgical morbidity 1

Recent evidence demonstrates that fluoroscopy-guided pneumatic enema and ultrasound-guided hydrostatic enema are "equally dependable and safe techniques" with high success rates 1. This approach directly impacts mortality and morbidity by:

• Avoiding general anesthesia and laparotomy when successful 1
• Preventing bowel resection in reducible cases 1
• Allowing immediate surgical intervention if reduction fails 1

Why Other Options Are Insufficient as the Primary Step

Bowel rest and IV hydration (Option A): While supportive care with intravenous crystalloids, anti-emetics, and bowel rest should begin immediately 2, this alone does not address the underlying mechanical obstruction. The World Journal of Emergency Surgery guidelines emphasize that supportive treatment "must begin as soon as possible" but is adjunctive, not definitive 2. In intussusception, delayed definitive treatment increases the risk of bowel ischemia, perforation, and need for resection.

Intravenous antibiotics (Option B): Antibiotics are indicated when there are signs of bowel ischemia, perforation, or septic shock 2. While this infant is "slightly pale" suggesting possible hypovolemia, there is no mention of peritonitis, fever, or hemodynamic instability that would make antibiotics the priority over definitive diagnosis and treatment.

Immediate surgery (Option C): Surgery should be reserved for failed enema reduction, signs of perforation, or peritonitis 2, 1. Proceeding directly to surgery without attempting enema reduction exposes the child to unnecessary operative morbidity when 70-90% of intussusceptions can be successfully reduced non-operatively 1.

Recommended Management Algorithm

1. Immediate resuscitation: Establish IV access, begin fluid resuscitation with isotonic crystalloids, insert nasogastric tube for decompression, and correct electrolyte abnormalities 2

2. Confirm diagnosis with ultrasound if available: Ultrasound has "high diagnostic accuracy and lack of ionizing radiation" making it the preferred diagnostic modality 1

3. Proceed to enema reduction: Either fluoroscopy-guided pneumatic or ultrasound-guided hydrostatic enema 1

4. Surgical consultation standby: Have pediatric surgery immediately available in case of:

   • Failed reduction attempt 1
   • Signs of perforation during the procedure 1
   • Evidence of pathologic lead point 1

5. Post-reduction observation: Monitor for recurrence (occurs in 5-10% of cases) 1

Critical Pitfalls to Avoid

• Delaying definitive intervention: Prolonged conservative management increases risk of bowel necrosis and perforation 2, 4
• Missing contraindications to enema reduction: Free air (perforation) or peritonitis are absolute contraindications requiring immediate surgery 2
• Inadequate resuscitation before procedure: The infant's pallor suggests hypovolemia that must be corrected first 2
• Assuming all obstructions in this age group are intussusception: While most likely, other causes include malrotation with volvulus (though less common at 15 months), incarcerated hernia, or Meckel's diverticulum 2