Chapter 27: Surgical Intensive Care Unit
A 55-year-old African American man with a history of hypertension, a 30-pack-year history of smoking, alcohol use, and peripheral vascular disease was complaining of nausea, vomiting, abdominal pain, and melanic stools. Two weeks ago, he had an endovascular repair of his abdominal aortic aneurysm. In the emergency department (ED), his vital signs were blood pressure (BP) of 90/60 mmHg, heart rate (HR) of 122 beats/min, respiratory rate (RR) of 22 breaths/min, oxygen saturation of 95% on room air, and temperature of 97.8°F. His physical examination was unremarkable except for a tender, distended abdomen. He had a CT of the abdomen and pelvis which showed inflammatory stranding and gas between the aorta and the small intestine.
What is the most common area of involvement with this disease?
The patient has an aortoenteric fistula, which is an abnormal connection between the aorta and the gastrointestional tract. It is considered primary when the abnormal connection is caused by compression of the abdominal aortic aneurysm against the gastrointestinal tract (usually the duodenum). It is considered secondary when the abnormal connection is due to erosion of a prosthetic aortic graft into the intestinal tract. The pathogenesis of a secondary aortoenteric fistula includes the following: mechanical pulsation of the aortic graft against the intestine, failure to suture all aortic layers, failure to separate the graft from the intestine, and endoleak., Aortoenteric fistulas can also occur in the stomach (choice B), large intestine (choice C), and cecum (choice D).
Diagnosis is difficult, and the triad of abdominal mass, gastrointestinal bleeding, and abdominal pain occurs only in 10% to 12% of patients. Other presentations include thrombosis with ischemia, weight loss, and sepsis. Gastrointestinal bleeding may temporarily cease (known as a “sentinel bleed’) and then be followed by severe decompensation. Computed tomography angiography without oral contrast has been suggested as the first-line imaging modality, with sensitivity and specificity as high as 94% and 85%, respectively. Ectopic gas adjacent to or in the aorta, bowel thickening, discontinuation of the aortic wall, and contrast extravasation into the bowel lumen can suggest an aortoenteric fistula. Fifty percent of diagnostic laparotomies are falsely negative.
Treatment includes resuscitation, tissue debridement, intestinal repair or resection, ostomy, and revascularization. This is achieved via open aortic repair or endovascular aneurysm repair.
A 55-year-old African American man with a history of hypertension, a 30-pack-year history of smoking, alcohol use, and peripheral vascular disease was complaining of nausea, vomiting, abdominal pain, and melanic stools. Two weeks ago, he had an endovascular repair of his abdominal aortic ...