Case Presentation: A 54-year-old female presented with painful swelling in the left lower extremity. She had a similar complaint over 30 years ago when she was on oral contraceptives and was eventually diagnosed with a deep venous thrombosis(DVT) in the left leg. Vitals showed an oral temperature of 36.7degree celsius , heart rate of 76, Blood pressure of 129/88 , respiratory rate of 18 while saturating at 99 on room air. An ultrasound showed a DVT in all the deep veins of the left leg.She was started on a heparin drip. The following day , she developed vaginal bleed and investigations confirmed endometrial cancer. She was discharged home on coumadin. She presented 8 months later with recurrent painful swelling of the left lower limb while her INR was therapeutic at 2.4. An ultrasound and later a CT confirmed that she had a DVT in left femoral and iliac veins which appeared to have increased in size since the last time. This prompted the search for an alternate cause for recurrent DVT at the same site. A venogram showed chronic occlusion of the left common iliac vein at the site of crossing over from right iliac artery . Angiogram revealed a patent right iliac artery. This established the diagnosis of May Thurner Syndrome. She underwent a left common femoral vein endarterectomy and bypass to profunda with iliocaval stenting .
Discussion: May Thurner syndrome involves an aberrant right common iliac artery compressing the left common iliac vein against the lumbar spine. Its incidence is about 20-50 % of left lower extremity DVTs. It is often missed as patients have other risk factors explaining the DVT such as OCPs , prolonged travel or as in the current case , malignancy. Such patients often develop chronic , recurrent DVTs and its ensuing complications. It can be a challenging diagnosis to make with conventional investigations. The gold standard test is a venogram which can also be therapeutic if endovascular therapy is employed. A CT venogram is as accurate as an intra venous ultrasound in delineating the compression of the iliac vein and is often sufficient to make a diagnosis and planning a possible intervention. Treatment involves removal of the thrombus either by chemical thrombolysis or surgical thrombectomy followed by angioplasty with stent placement to maintain patency.The recurrence of symptoms with thrombus extension while on a therapeutic INR aroused suspicion about the diagnosis in our patient. The vascular surgery team performed the venogram as a CT venogram did not prove to be very useful given the extensive thrombosis and presence of collaterals. Once it was surgically repaired she has remained symptom free for over 3 months and counting.
Conclusions: Hospitalists who encounter recurrent left lower extremity DVT must entertain the diagnosis of May Thurner Syndrome even if other risk factors for DVT are present.