Case Presentation: A 54-year old male with dementia and chronic kidney disease presented to the emergency room with bilateral lower extremity swelling and blistering in lower legs and calves for several weeks duration. His initial vitals were within normal limits. Examination revealed multiple tense fluid filled bullae in medial lower leg to the foot on his right and left lower extremities (Figure). They were primarily located in the distribution of saphenous veins. He also had several erosions around the medial side of his right knee. Femoral pulses were palpable 2+, dorsalis pedis and posterior tibial pulses were only dopplerable. A venous Doppler ultrasound study showed extensive occlusive thrombus in the left common femoral, superficial femoral, greater saphenous, and popliteal veins. Heparin drip was initiated for the clot and a CT lower extremity was done to rule out necrotizing fasciitis given the amount of swelling. Imaging showed concern for phlegmasia dolens given extensive iliofemoral thrombosis and May-Thurner syndrome. Vascular surgery performed urgent mechanical thrombectomy of the left common iliac, external iliac, common femoral, and popliteal veins. Intravascular ultrasound (IVUS) confirmed aortic bifurcation compression on caval bifurcation as well as left common iliac vein compression between right common iliac and spine. Several wall stents were deployed at the left common and external iliac veins with post stent angioplasties due residual clot. He was discharged on apixiban for anticoagulation.
Discussion: Skin findings from extensive VTE and PCD are often nonspecific. Marked swelling and cyanosis of the limb can occur. More often, techniques such as ultrasonography are performed to evaluate venous status. We demonstrate one of the few cases where acute on chronic VTE, including blockage of a large proximal vein, led to formation of large bullae and blistering. It is hypothesized that this was due to change in venous return due to interstitial fluid hydrostatic pressure, and lead to separation of epidermal cells at level of the skin leading to these findings. The treatment strategy here is initially anticoagulation, then subsequent angioplasty and stenting if applicable; quick relief of the obstruction is key to avoiding future limb amputation.
Conclusions: May Thurner syndrome is a severe variant of venous thromboembolism (VTE) where the iliac vein is extrinsically compressed by the arterial system, vertebrae, other bony structures. Symptoms include extremity pain, swelling, venous insufficiency such as skin discoloration and ulceration. Phlegmasia Cerulea Dolens (PCD) is a severe complication of VTE where compartment syndrome can occur due to the swelling of the extremity. Here is an unusual case where an initial presentation of hemorrhagic bullae in the lower extremities was due to extensive VTE burden. We have learned anatomy that comprises May-Thurner syndrome leading to venous outflow obstruction, reviewed initial noninvasive vascular imaging for suspicion of phlegmasia, and described vascular interventions for extensive iliocaval venous clots.
