Ruptured Isolated Common Iliac Artery Aneurysm Masquerading as Renal Colic

Urinary stone disease is a common problem globally. Ureteric colic typically presents with flank pain and hematuria. However, several conditions may give a similar clinical picture. Hence, imaging studies are essential to make the diagnosis of urinary stone disease and evaluate for possible complications. We present the case of a 64-year-old man who presented with severe left flank pain radiating to the groin for two days. In his first visit to the emergency department, he was prescribed conservative treatment, but it failed to give any clinical improvement. The patient does not have a previous history of urinary stone disease. He had a long-standing history of hypertension, diabetes mellitus, dyslipidemia, and coronary artery disease. Further, he had a 30 pack-years history of smoking. Upon examination, the abdomen was soft and lax with generalized tenderness. Subsequently, a non-contrast computed tomography scan for the kidneys, ureters, and bladder was performed, which demonstrated a large high attenuation fluid seen in the left side of the retroperitoneum. The scan was then repeated after the administration of intravenous contrast and showed an aneurysmal dilatation of the left common iliac artery with surrounding hematoma. The patient was taken for an emergency laparotomy for evacuation of the hematoma and graft repair of the aneurysm. The patient tolerated the operation without complications. The present case highlights the importance of considering the wide differential diagnoses of flank pain in emergency settings. Physicians should keep a high index of suspicion for aneurysmal disease when they encounter patients with risk factors for arterial wall degeneration.