Segmental arterial mediolysis: a rare cause of an acute abdomen.

Segmental arterial mediolysis (SAM) is a nonatherosclerotic, noninflammatory and nonimmune arteriopathy of unknown aetiology. We present the case of a 43-year-old male who presented to the emergency department with abdominal pain. A computed tomography of abdomen and pelvis showed a narrow, hypodense superior mesenteric artery after the origin, raising the possibility of thrombus or vasculitis. He was commenced on rivaroxaban and steroids. He subsequently presented with an acute abdomen in a collapsed state. Repeat imaging of his abdomen and pelvis revealed an ischaemic ileal segment and caecum. He required an emergency laparotomy with resection of the ischaemic segment and formation of a double-barrelled stoma. SAM is an important diagnosis for clinicians and radiologists to be aware of, given the risks of life-threatening haemorrhage and acute organ ischaemia. This is a commonly overlooked cause of abdominal pain, where an early diagnosis with lifestyle modifications may prevent disease progression and subsequent development of life-threatening complications.