Gastroenterology · Pediatric GI Emergencies
The facts most likely to be tested
Intussusception typically presents in infants aged 6 to 36 months with intermittent, colicky abdominal pain causing the child to draw their legs toward the chest.
The classic physical exam finding is a sausage-shaped mass in the right upper quadrant or epigastrium accompanied by emptiness in the right lower quadrant known as the Dance sign.
Stool findings often progress to currant jelly stool, which represents a mixture of mucus and sloughed mucosa resulting from venous congestion and ischemia.
The diagnostic modality of choice is an abdominal ultrasound, which classically demonstrates the target sign or doughnut sign representing concentric layers of the bowel.
An air-contrast enema or water-soluble contrast enema serves as both the diagnostic and therapeutic intervention for stable patients.
The most common pathologic lead point in older children is Meckel diverticulum, whereas in infants, it is often lymphoid hyperplasia following a viral infection.
Immediate surgical consultation is required if the patient presents with signs of peritonitis, shock, or evidence of bowel perforation on imaging.
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A 9-month-old male is brought to the emergency department by his parents due to episodes of inconsolable crying followed by periods of lethargy. The mother notes that the infant pulls his knees to his chest during these episodes. On physical examination, the infant appears pale and a sausage-shaped mass is palpated in the right upper quadrant. A digital rectal exam reveals currant jelly stool on the gloved finger.
What is the most appropriate next step in the management of this patient?
Air-contrast enema
The patient presents with the classic triad of intussusception; in a hemodynamically stable patient without signs of perforation, an air-contrast enema is the gold standard for both diagnosis and reduction.
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Etiology / Epidemiology
Most common in infants 6-36 months; often follows a viral infection (hypertrophied Peyer patches).
Clinical Manifestations
Colicky abdominal pain, currant jelly stool, and a sausage-shaped mass.
Diagnosis
Air contrast enema is both diagnostic and therapeutic; ultrasound shows target sign.
Treatment
Air enema is first-line; peritonitis or perforation are absolute contraindications.
Prognosis
High success rate with reduction; 10% recurrence rate; monitor for bowel necrosis.
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Epidemiology & Etiology
Peak incidence occurs between 6 and 36 months of age. In older children, consider a pathologic lead point such as Meckel's diverticulum, lymphoma, or Henoch-Schönlein purpura. Most cases in infants are idiopathic, likely triggered by viral-induced lymphoid hyperplasia.
Pertinent Anatomy
The most common site is the ileocolic junction. The proximal bowel (intussusceptum) telescopes into the distal bowel (intussuscipiens), leading to venous congestion and edema.
Pathophysiology
Telescoping of the bowel causes venous obstruction and mucosal edema, resulting in the classic currant jelly stool (sloughed mucosa and blood). If untreated, this progresses to arterial compromise, ischemia, and eventually bowel perforation.
Clinical Manifestations
Patients present with sudden onset of intermittent, severe colicky pain causing the infant to draw legs to the chest. Physical exam reveals a sausage-shaped mass in the RUQ and an empty RLQ (Dance sign). Bilious vomiting and lethargy are late-stage signs of obstruction and shock.
Diagnosis
Abdominal ultrasound is the initial imaging of choice, demonstrating the target sign or pseudokidney sign. The air contrast enema is the gold standard for both diagnosis and reduction, providing higher safety than barium.
Treatment
Perform air enema reduction under fluoroscopic guidance for stable patients. Peritonitis, shock, or free air on X-ray are absolute contraindications to enema and mandate emergent surgical consultation. If enema fails or perforation occurs, surgical reduction is required.
Prognosis
Successful reduction carries an excellent prognosis. Parents must be counseled on a 10% recurrence rate, typically within the first 24-48 hours. Monitor closely for signs of sepsis or peritonitis post-reduction.
Differential Diagnosis
Gastroenteritis: usually associated with diarrhea and fever, lacks sausage mass
Meckel's diverticulum: painless hematochezia is more common than obstruction
Appendicitis: RLQ tenderness and guarding, not episodic pain
Volvulus: presents with bilious vomiting and signs of malrotation
Henoch-Schönlein purpura: associated with palpable purpura and joint pain