411. Granulomatosis with Polyangiitis presenting with typical features of Giant cell arteritis

Presentation of Case: A 63-year-old female presented with PMR with CRP 37mg/L and ESR 80mm/hr. Prednisolone 15mg resulted in a marked response. On weaning prednisolone to 10mg she developed headaches, scalp tenderness, jaw claudication and diplopia prompting an increase of prednisolone to 60mg. Diagnostic testingTemporal artery biopsy was in keeping with GCA (Fig. 1A&B). Her headaches settled, but she developed rhinnorhoea, epistaxis, vasculitic rash and shortness-of-breath. Urinalysis demonstrated no casts. Chest-Xray revealed right-sided consolidation (Fig. 1C) and CT sinuses confirmed mucosal thickening (Fig. 1D). Inflammatory markers remained elevated ESR 39mm/hr and CRP 59mg/L with a normal creatinine 71µmol/L [62-124]. Differentail and final diagnsosis C-ANCA was positive with PR3 114 IU/ml [0-3.1] confirming the diagnosis of GPA. Nasal biopsy demonstrated inflammation without granulomatous changes. She received prednisolone 1mg/Kg and intravenous Cyclophosphamide. Azathioprine maintenance was initiated once she was in remission. Discossion of management Our case highlights GPA can present with features typical of GCA. This is important as the treatment and prognosis are different with systemic steroids usually sufficient to treat GCA, but GPA requires additional Cyclophosphamide or Rituximab therapy. Conclusion: Large vessel vasculitis [LVV] can be a feature of GPA and may affect aorta, subclavians or carotid arteries. LVV often presents at the time of initial diagnosis of GPA, but may precede or occur after the GPA diagnosis [1, 2]. Disclosures: Non