Introduction: Inferior vena cava (IVC) thrombosis is associated with high morbidity. Common causes include the presence of an IVC filter, malignancy, congenital abnormalities, thrombophilia, or trauma. Delayed treatment may lead to post-thrombotic syndrome or pulmonary embolism with potentially fatal outcome (1, 2).

Case report: 44-year-old male with no significant medical history presented to the emergency department with acute pain in the left groin and swelling of the left leg. Duplex ultrasound showed slow flow in the dilated left common femoral vein, with absent respiratory flow modulation, suggesting a proximal obstruction. Computed tomography (CT) venography revealed narrowing in the suprarenal segment of the IVC with intraluminal calcification and stenosis of the right renal vein, accompanied by formed venous collaterals, suggesting unrecognized prior thrombosis. Partial thrombosis of the infrarenal IVC and complete thrombosis of left iliac veins was also noted, along with bilateral lobar pulmonary embolism with no signs of right heart strain (Figure 1). Upon admission, the patient was immediately started on low molecular weight heparin. Further workups for thrombophilia, malignancy and urological pathology returned negative. Detailed history revealed that he was an ultra-distance trail runner, a factor that may have contributed to thrombosis via dehydration and endothelial injury. Given the favorable clinical course he was discharged with a recommendation for long-term anticoagulation with rivaroxaban. Follow-up at 2 months showed normalization of D-dimers and sonographic improvement. After 5 months, CT venography revealed significant recanalization of affected vessels, and the patient was in excellent clinical condition, without venous claudication or leg swelling (Figure 2).

Conclusion: IVC thrombosis is an under-recognized condition, commonly associated with malignancy or thrombophilia. Abdominal trauma, microtrauma, and dehydration related to intense physical exertion, particularly in athletes, can also contribute to its development. Current guidelines for IVC thrombosis management are limited, but anticoagulation remains essential, while interventional treatment may be considered depending on the disease severity (2, 3).