Abdominal aortic aneurysm presenting with intensive rectal bleeding

Introduction:Although hematochezia has many causes, it can be a sign of a serious problem. Most common causes are hemorrhoids and diverticulosis, both of which are relatively benign; however, it can also be caused by colorectal cancer. Not always the source of the bleeding is from GI tract; also, abdominal aneurysms and fistula can lead to such manifestations.Purpose: When the bleeding is unusual for a GI source, other sources must be evaluated and be found. Case report:A ۵۶-year-old man presented to the emergency department with an episode of rectal bleeding, melena, dizziness subsequently syncope and mild crampy abdominal pain. He had intermittent rectal bleeding for the last ۱۵ days. The bleeding became more intense in the last ۴ hours. He had nausea but no vomiting. He denied hematemesis or weight loss. He had no fever, chills, sweats, chest pain, shortness of breath or hematuria. He denied taking any anticoagulants or antiplatelet agents. He had an extensive smoking history, alcohol abuse and hypertension. The patient had previous history of an Aortoiliac aneurysm managed by an elective surgical intervention. On physical examination, vital signs were normal. Tilt test was positive. The abdomen was non tender without palpable masses, abnormal pulsations, or organomegaly. There was mild epigastric tenderness, but no rebound, guarding or peritoneal signs. Digital rectal examination revealed blood mixed with stool. No pathologic finding was reported in ECG and chest X-ray. Laboratory data indicated: Hb :۸,۵, pt:۱۴.۲, ptt: ۳۲, INR:۱.۱, WBC:۱۰.۲, PLT:۳۲۱, NA:۱۳۴, K:۴.۸ and Cr:۱.۶. The patient was resuscitated saline and packed red blood cells. Nasogastric tube was placed and gastric washing was done. His differential diagnosis included gastritis, ulcer disease, inflammatory bowel disease, and Meckel’s diverticulum. Endoscopic evaluation revealed a small erosion of the rectal mucosa. Colonoscopy revealed tarry stool in the right colon, diverticulosis of the left colon; no bleeding site was seen. Also, esophagogastroduodenoscopy revealed a large blood clot in the fundus and upper body of the stomach. ۲۴ hours later, the patient had recurrent bleeding. in repeated upper endoscopy, no source of bleeding could be found. Because of the sudden onset of profound hypotension with associated pain, which is unusual for a GI bleeding, a CT scan of the abdomen was performed to evaluate the patient’s aorta. The CT scan without contrast revealed a dilated infra-renal aorta with a hyperdense crescent to the right. The CT scan with i.v. contrast revealed a ۴.۰ cm infra-renal AAA with a bulge to the right, but without rupture, and with a small amount of contrast identified in the duodenum.The vascular surgeon elected to obtain an angiogram to differentiate upper GI bleeding versus PAEF. The angiogram revealed a ۴.۰-cm infrarenal AAA with a penetrating ulcer and a questionable fistula tract. Thus, an emergent exploratory laparotomy was performed confirming an aortoduodenal fistula, which required graft and repair of the duodenal fistula. The patient’s remaining hospital course was uncomplicated, and he was discharged home on the sixth postoperative day.Conclusion:Abdominal aortic aneurysms often grow slowly without noticeable symptoms, making them difficult to detect. Some aneurysms never rupture. Many start small and stay small. Others grow larger over time, sometimes quickly. Other symptoms include deep, constant pain in the abdomen, back pain or a pulse near the navel. Also, when the bleeding from GI tract can’t be justified by GI sources, CT scan must be performed and other sources like aortic aneurysm and fistula must be taken into consideration.