1662 Colonic Obstruction Leading to a Diagnosis of Polyarteritis Nodosa

Abstract

INTRODUCTION: Polyarteritis Nodosa (PAN) is a rare systemic necrotizing vasculitis that preferentially affects medium-sized arteries. Patients may present with systemic symptoms or with isolated organ involvement. PAN may involve the gastrointestinal (GI), renal, cardiac, musculoskeletal, skin and central nervous systems. When the GI tract is involved, abdominal pain is the most common presentation, thought secondary to transmural necrotizing inflammation of the mesenteric vessels leading to bowel ischemia. The small bowel is the most common site of involvement. Ischemic mucosal ulceration, bowel infarction and perforation can result. Case reports in the pediatric literature and a retrospective case series have described PAN causing severe GI strictures leading to intestinal obstruction. We report a rare case of PAN leading to a colonic obstruction. CASE DESCRIPTION/METHODS: A 36-year-old-male was admitted to the hospital with nausea, vomiting, abdominal pain and reduction in the passage of stool and gas for the previous 5 months. Computerized topography of the abdomen and pelvis demonstrated colonic dilatation and obstruction at the level of the sigmoid colon. A flexible sigmoidoscopy was performed and identified severe stenosis at the recto-sigmoid junction, 25 cm from the anal verge. This area could not be traversed with an upper endoscope or an ultrathin endoscope. Given the near complete obstruction of the sigmoid colon, exploratory laparotomy was performed, which revealed a sigmoid stricture with densely adherent loops of small bowel. Sigmoidectomy with en bloc small bowel resection was performed. Pathology demonstrated mucosal ulceration with transmural inflammation and injury of the medium-sized vessels. Some of the medium-sized vessels in the mesentery had evidence of acute injury, while others appeared to be in the healing state with obliteration and recanalization of the lumen. This admixture of early and late lesions was felt consistent with PAN. The patient was discharged with GI, surgery and rheumatology follow up. DISCUSSION: PAN is a rare systemic vasculitis that can present with a wide range of symptoms including abdominal pain, nausea, vomiting, GI bleeding, diarrhea and weight loss. Intestinal stricture due to bowel ischemia can occur with resultant obstruction. The small intestine is the most common site of ischemia in the GI tract. As such the differential diagnosis of intestinal strictures should include chronic ischemia from systemic vasculitis.