Vasculitis Mimic Clinic: Challenges with Arteriopathy

Summary: Background: Vasculitis is inflammation of a blood vessel that may lead to endothelial injury and subsequent thrombosis. Hepatic artery thrombosis seldomly occurs in patients without orthotopic liver transplantation, however vasculitides are a known cause of this rare pathology. A diagnostic challenge occurs when a thrombosis or non-inflammatory arterial condition mimics vasculitis. Case: A 67-year-old female presented to the emergency department from her primary care provider’s office with right upper quadrant abdominal pain. Ten days prior, the patient had severe diarrhea with epigastric abdominal pain. Over the initial week, the pain progressed to the right upper quadrant and radiated to the mid-thoracic region and was associated with night sweats and anorexia. Patient presented to an outside emergency department where a right upper quadrant ultrasound showed nonspecific mild gallbladder wall thickening. She was discharged to primary care for a general surgery referral for non-emergent cholecystectomy. At her primary care provider’s office, the patient was hypertensive and continued to have constant epigastric and right upper quadrant abdominal pain. She denied any fevers or vomiting, but endorsed poor oral intake prompting transfer to the emergency department for further imaging. Initial complete blood count and comprehensive metabolic panel were unremarkable. A CT abdomen and pelvis with contrast revealed enlargement of the distal common hepatic artery with an abrupt transition to a poorly opacified proper hepatic artery, consistent with a hepatic artery thrombosis. The patient was anticoagulated and admitted for vascular surgery evaluation to work up the etiology of the thrombosis. The patient is a previously healthy veteran, with a past medical history of well-controlled hyperlipidemia, hypertension, urge incontinence, chronic pain, and vasomotor symptoms of menopause on oral estradiol. On the following day, a three phase liver CT demonstrated diffuse wall thickening and irregularity throughout the superior mesenteric artery, proper and common hepatic artery, and right hepatic artery consistent with vasculitis (Figure 1). Given these findings, the hospital team suspected medium vessel vasculitis was the etiology of the hepatic artery thrombosis and rheumatology was consulted. The patient denied any personal or family history of any rheumatologic conditions and denied any rashes, mouth ulcers, joint pain, Raynaud’s phenomenon, pleuritic chest pain, or jaw claudication. Laboratory studies including ANA, anti-dsDNA, anti-SS-A/B, anti-Sm, anti-centromere, anti-Jo-1, anti-Scl-70, ANCA, as well as rheumatoid factor, ESR, and CRP were obtained. All assays were within normal limits except a mildly elevated CRP of 3.5 and ESR of 22. Hypercoagulability and malignancy workups were also negative. With unrevealing laboratory findings and in the absence of systemic features such as skin or kidney involvement, there was low suspicion of polyarteritis nodosa or Behcet disease. Furthermore, it was thought that an acute thrombosis may have caused the vessel structure changes seen on CT versus a non-inflammatory, non-atherosclerotic arteriopathy such as fibromuscular dysplasia or segmental arterial mediolysis. The patient’s pain significantly improved following the initiation of anticoagulation, and she was discharged from the hospital in stable condition. Six weeks later, a follow up three phase liver CT showed no complete vessel occlusion with interval decrease in arterial wall thickening and perivascular soft tissue. However, there was persistent irregularity of the superior mesenteric artery, proper and common hepatic artery, and right hepatic artery with segments of marked luminal narrowing as well as areas of aneurysmal dilation. Discussion: This case demonstrates a causality dilemma of a hepatic artery thrombosis with imaging characteristic of vasculitis. Hepatic artery thrombosis rarely occurs in patients without liver transplantation and it was prematurely presumed that vasculitis was the cause in this patient. There are several conditions without vascular inflammation that can mimic vasculitis as well as vessel changes that may be seen in the setting of acute thrombosis. For this patient, serial CT scans are being performed for surveillance as she undergoes further workup for her arteriopathy. Conclusion: Irregular tapering and stenosis on arterial imaging is characteristic of vasculitis, but is non-diagnostic. Prompt identification of mimickers of vasculitis will prevent unnecessary testing and immunosuppressive therapy.