S2142 The Importance of Suspecting Intussusception as a Cause of Adult Bowel Obstruction

Abstract

Introduction: Adult intussusception is rare, accounting for 5% of all cases of intussusception, and 1%-5% of all intestinal obstruction. It is mostly idiopathic in children, but in adults, up to 90% are secondary to a pathologic process. We present a case of an elderly man who presented with bowel obstruction as a result of intussusception due to colonic adenocarcinoma. Case Description/Methods: A 73-year-old man presented with hypotension and tachycardia after large volume melena, and 4 days of colicky abdominal pain, anorexia and vomiting. He has a history of ESRD, multiple myeloma and GERD. Blood pressure was 97/64 mmHg & pulse was 123. He was pale, dehydrated, and had a distended, diffusely tender abdomen, without masses or guarding. Rectal exam revealed melanotic stool without masses. His hemoglobin was 8.1, lactate 2.7, and chest XRAY was normal. Patient was stabilized, GI was consulted, and he was admitted for hypotension due to massive GI bleed. Abdominal CTA showed bowel within bowel configuration, consistent with colonic/ileocolic intussusception from the hepatic to splenic flexure, with mesenteric bleeding inside the bowel loop, and fat stranding. Surgery emergently performed laparotomy, finding intussusception from cecum to transverse colon, with a cecal mass as the lead point. Mass resection and right hemicolectomy were done, after which he had a brief ICU stay and was eventually discharged. Pathology revealed a 3.7 cm well-differentiated adenocarcinoma with submucosal invasion (Figure). Discussion: Intussusception is the telescoping of a segment of bowel into the lumen of adjacent distal bowel. In children, it usually presents with cramping abdominal pain, bloody diarrhea and a palpable mass. In adults 19 - 90 yrs however, it may present atypically, and is a completely distinct entity, warranting a greater degree of attention, as it is commonly caused by tumors, ∼50% of which are malignant, most commonly primary colonic adenocarcinoma, followed by carcinoids, sarcomas and metastasis. Our patient presented with obstructive symptoms and rectal bleeding, which can be due to any form of bowel obstruction, making the suspicion of intussusception challenging, and often overlooked. It can be diagnosed with 58-100% accuracy with abdominal CT, and usually requires surgical treatment. Despite its rarity, intussusception should always be considered as a cause of bowel obstruction in adults, regardless of rectal bleeding, as it is significantly associated with cancer.Figure 1.: CT abdomen showing ileocecal intussusception with classic target sign on axial view (right), and bowel within bowel configuration on coronal view (right).