Case Presentation: A 57 y/o Caucasian woman with undifferentiated connective tissue disease (UCTD), hypertension, and hyperlipidemia, presented to the emergency department for worsening dyspnea and nasal congestion. She was diagnosed with COVID-19 and treated with Paxlovid. A week later, she developed chest and left upper quadrant abdominal pain that were unresponsive to antacids and pain medications. She returned to the hospital where CT imaging showed celiac axis vasculitis with associated splenic artery thrombosis and splenic infarcts. Labs were significant for ESR 103, CRP 71, negative ANCA, negative troponins, negative acute hepatitis panel, AST 27, ALT 140, and Cr 1.0. She was treated with high dose steroids, methotrexate and apixaban. With improvement of her symptoms, she was discharged with rheumatology follow-up. She returned to the hospital a week later with recurrence of her chest pain, described as severe, sharp and aching. Acute coronary syndrome and pulmonary embolism were ruled out. CTA head, neck, abdomen and pelvis were obtained. Findings were significant for undulating contours of the proximal right vertebral artery and proximal left internal carotid artery (ICA), and distal right cervical ICA 3mm aneurysm, in addition to proximal celiac artery changes along with thickening of common hepatic, proper hepatic, and splenic arteries. Vascular surgery and rheumatology were consulted, agreeing that her symptoms were not related to a vasculitis but to fibromuscular dysplasia (FMD). Methotrexate was stopped, and prednisone was tapered off. Aspirin was started.
Discussion: FMD is a non-inflammatory arterial disease that affects small and medium sized arteries, commonly the renal and carotid arteries. Although this patient had celiac axis involvement, FMD affecting large arteries is rare. Manifestations including stenosis and aneurysms are often found, leading to the “string of beads” characterization on angiographic imaging. It is typically found in women between the ages of 20 to 60 years old. Due to its likelihood of affecting multiple vessels and its high morbidity, all patients are recommended to undergo screening with imaging from head to pelvis. FMD has been termed a “pseudo-vasculitis,” as they can both present with multivessel involvement, aneurysms, stenosis, or dissection, leading to end organ damage. As vasculitis is an inflammatory condition, patients often present with fever, elevated inflammatory markers or thrombocytopenia, that are not commonly found with FMD. The patient’s rheumatologic history also contributed to a misdiagnosis, although it is uncommon for UCTD to cause vasculitis.
Conclusions: FMD can be mistaken for vasculitis. Misdiagnosis is significant leading to treatment delays and poor patient outcomes. Steroids and immunosuppression used for the treatment of vasculitis can harm the vascular wall, increasing the risk of arterial dissection or rupture. Long-term management of FMD is not well defined. Dissections are medically managed with antiplatelets and blood pressure control.
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