Arterial Thrombosis as an Uncommon Presentation of Granulomatosis with Polyangiitis: A Case Report.

Introduction: Granulomatosis with polyangiitis (GPA) is a primary vasculitis usually affect predominantly small vessels and also medium-sized blood vessels with diverse manifestation. The incidence of Granulomatosis with Polyangiitis (GPA) is estimated at 10–20 cases per million people in Europe and North America, with higher in the UK (11.3/million/year). It occurs in the aged 40–60 years with male predominance. It usually involves upper and lower respiratory with renal system. Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is associated with a greater risk of developing venous and arterial thrombosis. GPA and Rheumatoid arthritis (RA) may overlap in some cases, which is also rare. Lower limb ischemia due to medium-sized arteries is a rare manifestation in GPA. This report in medical literature extremely rare that provides valuable in diagnosis, management. Case Summary: We present a case of a 33 years old male who presented with poly arthralgia, fever, purpuric skin rash, and hemoptysis for a few weeks and later presented with sudden onset limb claudication. Physical examination revealed a purpuric skin rash on both lower limbs and palms, joint tenderness, and absent pulsation on the popliteal, dorsalis pedis (ADP), and posterior tibial arteries of the left lower extremity. Investigations showed anemia with high ESR and CRP levels, microscopic hematuria, elevated D-dimer levels, and Rheumatoid factor (RF) positivity in high titers. CT of chest revealed cavitary lesions. C-ANCA and Anti-proteinase 3 (PR3) antibody titers were positive. Duplex ultrasound and computed tomography (CT) angiography of the left lower limb revealed absent arterial flow distal to the popliteal artery. So, the patient was diagnosed as organ threatening GPA and treated with steroids, heparin, and intravenous rituximab and was discharged with outpatient rheumatology follow-up. Conclusion This unusual presentation of GPA presenting with arterial thrombosis and high titers of RF positivity. The report contributes to clinical awareness, helps in earlier recognition of similar cases, and gives the importance of considering systemic vasculitis in unexplained arterial thrombosis.