The impending abdominal aortic aneurysm rupture diagnostic dilemma: a case of misleading symptoms and concurrent life-threatening conditions

BACKGROUND: Symptomatic non-ruptured abdominal aortic aneurysm (AAA) is a diagnosis of exclusion. In this case report, we faced two vascular challenges: (1) establishing a diagnosis of impending rupture and (2) restructuring the intervention plan and timing after a second abdominal emergency was diagnosed and treated. CASE REPORT: A 72-year-old male presented to the emergency department with left lower quadrant abdominal pain lasting over 12 hours. Clinical assessment revealed a pulsatile midline abdominal mass and abdominal discomfort on palpation, without signs of peritoneal irritation. The patient was haemodynamically stable, and laboratory findings showed leucocytosis and elevated C-reactive protein. Abdominal computed tomography angiography revealed an infrarenal AAA measuring 85mm with features of impending rupture, and no findings suggestive of an alternative diagnosis. The patient was admitted to the vascular ward with the aim of intervening at the first elective opportunity, but worsening abdominal pain in association with hypotension prompted an emergent decision. Open surgical repair was chosen based on the aneurysm's anatomical features - a short neck (13 mm) with severe infrarenal angulation (approximately 90°). Intraprocedural bowel mobilisation revealed transmural ischaemia extending from the transverse colon to the mid-rectum. Collaboration with general surgery was arranged, and the patient underwent a Hartmann procedure. The patient subsequently underwent endovascular aortic repair (EVAR) 10 days after the first procedure. CONCLUSION: Ischaemic colitis is a recognised complication of major vascular surgery, particularly after AAA repair. In our case, the aetiology of colonic ischaemia was unclear, but it likely resulted from a state of hypoperfusion in a patient with atherosclerotic disease and poor collateral circulation. The patient presented with two life-threatening conditions, although only one was diagnosed in advance.