POLYARTERITIS NODOSA: A CASE REPORT OF ISOLATED LARGE BOWEL INVOLVEMENT AND SURGICAL INTERVENTION

Objectives:

Introduction:

Polyarteritis nodosa (PAN) is a necrotizing vasculitis commonly affecting small and medium-sized vessels. Though most cases are managed medically, we present the case of a patient requiring surgery for ischemic colitis secondary to polyarteritis nodosa.

Methods: Clinical

Case:

A 26-year-old woman presented with six weeks of left lower quadrant pain, diarrhea, and mucoid bloody stools. Blood work was significant for CRP of 27.7 and a white blood cell count (WBC) of 16,000. Colonoscopy showed diffuse circumferential ulceration and necrotic lining from the sigmoid colon to the splenic flexure. Biopsies showed focal, acute inflammation, ulceration, and fibropurulent exudates. A subsequent CTA (image 1) revealed left colonic wall thickening, hypoenhancement, and multiple inferior mesenteric artery aneurysms, concerning for vasculitis. Ensuing laboratory workup including Antinuclear Antibody (ANA), Antineutrophilic-Cytoplasmic Antibody (ANCA), Cytomegalovirus (CMV), histoplasma, treponemal, hepatitis panel returned negative.

Worsening abdominal pain, left-sided peritonitis, tachycardia, and rising WBC necessitated an exploratory laparotomy. Intraoperatively, the descending and sigmoid colon had a woody appearance. The patient underwent a colectomy from the proximal descending colon to the upper rectum with an end-colostomy. Surgical pathology showed active and healed necrotizing arteritis with ischemic ulcers. Small and medium-sized vessel walls were thickened with areas of necrosis, internal elastic lamina disruption, and inflammatory infiltrates in the media. Overall, this was consistent with polyarteritis nodosa.

The patient improved significantly within one day of surgery and was discharged on postoperative day 4 on steroid taper. She was started on Mycophenolate mofetil for PAN management postoperatively.

Results:

Discussion:

PAN can involve various organ systems, with GI involvement frequently implicating the gallbladder and small bowel. Isolated colonic involvement is a rare manifestation of PAN, and is represented in our case.

Clinically, GI-associated PAN can mimic inflammatory bowel disease and ischemic colitis related to hypoperfusion. Timely diagnosis is critical due to complications, including perforation, hemorrhage, ulceration, and obstruction. The medical management of PAN involves high-dose steroids and immunosuppressive agents. Surgical intervention is an infrequent treatment of PAN; however, an acute abdomen requires urgent resection of the affected bowel. As evidenced by this case, there is no specific laboratory test for PAN. Biopsies can identify features consistent with PAN and are the gold standard for definitive diagnosis.

Conclusion:

Conclusion:

Although PAN can affect the GI tract, this case is a unique presentation of isolated large intestinal involvement that initially resembled IBD and was treated with both medical and surgical interventions.