Venous thromboembolism (VTE) is a common diagnosis in the emergency department, affecting approximately 600,000 to 900,000 individuals per year in the United States, encompassing both deep vein thrombosis (DVT) and pulmonary embolism (PE) [1,2]. When approaching the workup and management of lower extremity swelling and suspected VTE, an emergency medicine physician is tasked with generating a comprehensive differential diagnosis, assessing for established risk factors such as recent surgery, prolonged immobilization, or malignancy, and performing a thorough vascular examination to determine the appropriate diagnostic pathway. There are validated clinical decision tools, such as the Wells Score for DVT and PE [[3], [4], [5]] and D-dimer testing [[3], [4], [5]], that aid emergency medicine physicians in determining pretest probability and whether to pursue advanced imaging; however, not all patients present with classic risk factors or typical presentations.

May-Thurner syndrome (MTS) is a venous compression syndrome in which the left common iliac vein is compressed between the lower lumbar spine and the right common iliac artery [6]. While most cases remain asymptomatic, it can cause severe morbidity in symptomatic individuals, most commonly deep vein thrombosis and post-thrombotic sequelae [6]. MTS is twice as common in women as it is in men, most often seen between 30 and 50 years of age, and accounts for approximately 2–5 % of all DVT cases [7]. The condition is exceedingly rare in the elderly population, making atypical presentations particularly challenging to recognize.

When clinical presentation is inconsistent with typical VTE presentations, particularly when there is pronounced asymmetric lower extremity swelling favoring the left side, emergency physicians should consider additional vascular imaging. The diagnosis requires specialized imaging, with intravascular ultrasound considered the gold standard, as it provides real-time, high-resolution images of the vein lumen and quantifies the degree of stenosis or obstruction [6,8].

We report on an elderly male with multiple comorbidities who presented to our emergency department with progressive bilateral leg swelling and shortness of breath, ultimately found to have extensive bilateral deep venous thrombosis with concomitant pulmonary embolism in the setting of May-Thurner syndrome, a diagnosis that requires prompt recognition and specialized intervention.