The Hidden Threat: Chronic Urinary Retention and Thromboembolism in Underlying May-Thurner Syndrome.

May-Thurner syndrome (MTS) is characterized by the formation of an intravenous scar or venous "spur" resulting from chronic pulsatile compression of the left common iliac vein (LCIV) by the right common iliac artery (RCIA) against the fourth or fifth lumbar vertebral body. This pulsatile compression creates a flow-limiting stenosis of the LCIV, leading to increased intravenous pressure in the veins draining the left lower extremity (LLE). Consequently, this elevated venous pressure manifests as a spectrum of chronic symptoms including unilateral LLE edema, pain, tenderness, warmth, skin inflammation, and discoloration, along with pelvic symptoms such as sensation of fullness and dyspareunia. Furthermore, MTS significantly elevates the risk of venous thromboembolism characterized by LCIV deep vein thrombosis (DVT) and potentially fatal pulmonary embolism (PE). Treatment options for MTS range from anticoagulant therapy to, in severe cases, operative intervention. Herein, we present a case of a 79-year-old male with MTS who experienced a near-fatal DVT that led to PE, compounded by a chronically distended urinary bladder, necessitating immediate operative removal of the PE.