Pediatric fibromuscular dysplasia presenting with acute right lower extremity limb ischemia requiring endovascular treatment and amputation – a case report

A 13-month-old female presented with acute right lower extremity discoloration, pain, and inability to bear weight. Examination revealed a purple/red limb with absent pulses and no Doppler signal. Imaging demonstrated aneurysmal dilation of the superior and inferior mesenteric arteries and right common iliac artery thrombosis with absent distal flow. Anticoagulation with a heparin infusion was initiated. During anesthesia for MRA of the head, neck, and body to evaluate vasculopathy, she developed a renovascular hypertensive crisis. Her limb worsened in appearance with progressive mottling, prompting left axillary access for thrombectomy and thrombolysis catheter placement which was effective. Aortogram and selective renal and visceral arteriograms revealed beaded appearance of the renal arteries suggesting fibromuscular dysplasia (FMD). Given demarcation of her ischemic right lower extremity, she underwent a right through-knee amputation. Pathology from the specimen confirmed extensive arteriopathy consistent with fibromuscular dysplasia. Persistent wound breakdown and lack of pulsatile flow required revision to an above-knee amputation with skin grafting and eventually revision amputation. She recovered well and is now ambulatory with a prosthesis. She remains on long term anticoagulation, antihypertensive therapy for renovascular hypertension, and beta blockade to possibly reduce visceral aneurysm rupture risk. This case illustrates a rare, severe presentation of FMD and underscores the need for prompt multidisciplinary evaluation and coordinated management.