Persistent Sciatic Artery Occlusion Presenting as Acute on Chronic Limb Ischemia in a Diabetic Elderly Male: A Rare Vascular Anomaly

Persistent sciatic artery (PSA) is a rare congenital vascular anomaly that can lead to limb-threatening ischemia when thrombosed. It is often misdiagnosed due to its rarity and overlapping symptoms with peripheral arterial disease (PAD). A 72-year-old male with a history of diabetes mellitus, hypertension, and ischemic heart disease presented with a 5-day history of progressive left lower limb weakness and calf pain exacerbated by walking over 200 meters. Examination revealed warmth of the limb, palpable left popliteal pulse, but absent dorsalis pedis and posterior tibial pulses. Duplex ultrasound revealed peripheral vascular disease with non-detectable flow in the distal posterior tibial artery (PTA)  and dorsalis paedis artery (DPA). Enoxaparin 60 mg twice a day and atorvastatin 40 mg were initiated, assuming acute on chronic limb ischemia. A subsequent CT angiogram revealed an occluded persistent sciatic artery with subacute thrombosis. This case highlights the importance of considering rare vascular anomalies like PSA in atypical presentations of limb ischemia. Early imaging with CT angiography is essential for diagnosis. Management may require anticoagulation, surgical intervention, or endovascular therapy depending on severity.