A 5-year-old girl presented to the emergency department with diffuse, predominantly periumbilical, colicky abdominal pain worsening for two days. The patient appeared uncomfortable on examination.
Abdominal ultrasonography was performed to exclude ileocolic intussusception, and an intussusception was visualized in the left flank. Real-time, physician-directed ultrasonography demonstrated that the intussusception was small, measuring 1.8 cm in diameter and likely represented a small bowel-small bowel intussusception. No right lower quadrant or midline ileocolic intussusception was seen.
Given the high degree of clinical concern by the emergency department, the patient underwent further imaging with a contrast-enhanced CT scan of the abdomen and pelvis that demonstrated a markedly dilated and hyperemic appendix with a small appendicolith and a small quantity of pelvic free fluid, consistent with acute appendicitis.
Small bowel-small bowel intussusceptions occur when a jejunal or ileal loop telescopes into the adjacent bowel. Prognosis and treatment are significantly different from ileocolic intussusception. Pure small bowel intussusceptions may be multiple and transient, and are associated with multiple additional evidence of intra-abdominal pathology.
Small bowel-small bowel intussusceptions may present a diagnostic dilemma within the emergency department. They are often idiopathic, but can be seen after upper respiratory infection including otitis media and rhinitis, rotavirus vaccination, enteric and nonenteric adenovirus infection, bacterial enteritis, in the setting of Henoch-Schönlein purpura, or due to pathological mechanical lead point such as a Meckel's diverticulum, duplication cyst, or a small bowel lymphoma. Small bowel intussusceptions present in a broader age category than ileocolic intussusceptions and can be seen in adults. Small bowel intussusception can be differentiated on ultrasound from ileocolic intussusception by its transient nature, smaller diameter, and decreased quantity of fat within the intussusceptum.
Approximately two-thirds of small bowel intussusceptions are transient and self-limiting, but surgical reduction may be required in some cases. Reduction enemas have no effect on small bowel intussusceptions but are not contraindicated if there is a diagnostic dilemma between small bowel and ileocolic intussusception. Most of the self-limited, self-resolving cases were noted to change in appearance within minutes under real-time ultrasonography. The presence of a visualized pathological lead point or small bowel intussusception longer than 3.5 cm are statistically significant predictors of which patients would ultimately require surgery.
As in our case, in the presence of symptomatology discordant with the imaging findings, diagnostic workup should be continued when a short small bowel intussusception is seen so any underlying cause or alternative diagnosis can be excluded.Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.