974 Paget-Schroetter Syndrome in A Young Fitness Enthusiast with A Negative D-Dimer. Highlighting the Balance Between Clinical Suspicion and Diagnostic Modalities

This case illustrates an athletic 22-year-old, who presented to the hospital with a 3-week history of spontaneous right arm ache, discolouration and swelling. His blood tests were normal, with a negative D-dimer (<150ng/ml). He underwent a CT venogram for suspicion of venous obstruction which was unremarkable. However due to a high clinical suspicion, an ultrasound doppler was performed. This identified the presence of axillary-subclavian thrombosis which in conjunction with other clinical and radiological parameters confirmed the diagnosis of Paget-Schroetter Syndrome (PSS). Our patient was commenced on anticoagulation as the venous obstruction was suspected to be sub-acute with clinical suggestion of collateral formation. Unfortunately, his symptoms failed to resolve over a 6-month period, and he underwent an elective right rib resection with right subclavian bypass using the great saphenous vein with good outcome post-operatively. PSS is a rare manifestation of venous thoracic outlet syndrome (TOS) commonly seen in young, healthy, athletic individuals. Despite the high effectiveness of D-Dimers in ruling out acute thrombotic process and the accuracy of dedicated CT angiography in excluding vascular thrombotic events, both tests proved inconclusive in this particular case. This latter observation highlights the importance of the clinical context, and risk profiling in guiding results interpretation.