A 3-year-old boy is brought to the emergency department due to abdominal pain. The pain began several hours ago and comes and goes. During these episodes, he holds his belly, screams, and draws up his legs. He has had nonbloody, nonbilious vomiting 3 times since the last painful episode. Between the episodes, the patient has no pain and is playful. His last bowel movement was yesterday and was normal. Two weeks ago, he had gastroenteritis that resolved after 3 days. He otherwise has no chronic medical conditions and takes no medications. Temperature is 37.2 C (99 F), blood pressure is 95/50 mm Hg, and pulse is 100/min. Abdominal examination shows a soft abdomen that is tender with voluntary guarding to palpation at the right upper and lower quadrants. Rectal examination reveals no fissures or hemorrhoids. The remainder of the examination is normal. Ultrasound of the abdomen is shown in the image below:
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Which of the following is the best next step in management of this patient?
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This patient has intussusception, the telescoping of one bowel segment into another. Intussusception is the most common cause of intestinal obstruction in children age 6-36 months. The ileocolic junction is most frequently involved, with invagination of the ileum into the colon. Most children have no identifiable lead point. However, a preceding viral infection (eg, gastroenteritis) is common and may lead to intussusception due to inflamed intestinal lymphatic tissue (eg, Peyer patches) serving as a lead point.
Intussusception classically presents with severe, periodic abdominal pain associated with drawing the legs up toward the abdomen. Emesis may follow episodes of abdominal pain and is initially nonbilious but may become bilious as the obstruction persists. Ongoing obstruction can also compromise circulation, causing mucosal ischemia, occult bleeding, and, if untreated, grossly bloody currant jelly stools. On occasion, the intussusception is palpable as a sausage-shaped abdominal mass. Although the ileocecal junction is normally located in the right lower quadrant, the invagination of the ileum into the colon often causes the mass to be found in the right middle or upper abdomen.
A target sign on ultrasound is diagnostic of intussusception and should prompt immediate treatment with an air or water-soluble contrast enema. Retrograde pneumatic (ie, air enema) or hydrostatic (ie, contrast enema) pressure reduces the telescoped bowel in most cases. Laparotomy is indicated if enema reduction is ineffective, if a pathological lead point is identified, or if the patient has signs of perforation (eg, free air on x-ray, rigid abdomen) (Choice C).
(Choice B) Although CT scan can identify intussusception, it cannot reduce the obstruction and would expose the patient to significant radiation. CT scan is indicated only if the ultrasound is unrevealing or if there is concern for pathological lead points.
(Choice D) HIDA scan is used to assess biliary pathology (eg, gallstones), which can cause intermittent right upper quadrant pain that is typically associated with eating. This patient's ultrasound is classic for intussusception.
(Choice E) Technetium-99m pertechnetate scan (ie, Meckel scan) can detect gastric mucosa, which is often present in Meckel diverticula, a potential lead point usually seen in recurrent intussusception. This patient is experiencing a first episode, and reduction of the acute intussusception is the priority.
Educational objective:
Intussusception presents in children age 6-36 months with periodic abdominal pain. A target sign on ultrasound should prompt reduction with air or water-soluble contrast enema.