Co-Presentation of Giant Cell Arteritis and Granulomatosis with Polyangiitis: A Case Report and Review of Literature.

BACKGROUND Systemic vasculitis can present with a multitude of symptoms involving multiple organ systems. Clinicians should avoid anchoring bias and be cognizant that different types of vasculitides can be present in the same patient and that the diagnosis of one should not preclude the subsequent diagnosis of another. CASE REPORT A 67-year-old woman was referred for evaluation of episodes of epistaxis and recurrent severe sinusitis. Her physical examination showed nasal congestion and purpuric rash on the lower extremities. CT of the sinuses showed severe mucosal thickening. ANCA serologies were positive with a c-ANCA titer of 1: 5120 and anti-proteinase-3 (anti-PR3) antibodies of 1061 units. Serum creatinine was elevated at 1.32 mg/dL (GFR of 40.62 ml/min). Urine analysis showed proteinuria and hematuria. The patient declined treatment initially, but while awaiting kidney biopsy she developed episodes of headache and blurry vision. She underwent right temporal artery biopsy 4 days later, which confirmed the diagnosis of GCA. The biopsy showed characteristic histopathology findings and she was started on 60 mg of prednisone daily. The kidney biopsy showed pauci-immune crescentic glomerulonephritis (PICGN) consistent with ANCA-associated vasculitis. We identified all the cases of co-presentation of GCA and GPA in the literature and summarized their clinical features in this report. CONCLUSIONS Astute clinicians should be cognizant of overlapping and atypical presentations of vasculitides to avoid delayed diagnosis and errors in management.