Granulomatosis with Polyangiitis: Role of Nephrologist in Management of a Rare Systemic Disease

Introduction: Granulomatosis with polyangiitis (GPA) is a rare form of systemic vasculitis primarily affecting the upper respiratory tract, lungs, and kidneys and associated with antineutrophil cytoplasmic antibodies (ANCA). This case highlights the importance of the nephrologist in the interdisciplinary management of GPA with a multisystemic presentation. Case Description: A 39-year-old African American female presented with a saddle nose deformity and chest pain. A computed tomography (CT) scan revealed mediastinal lymphadenopathy, numerous lung masses, and total obstruction of the nares. A nasal biopsy showed pyogenic granuloma. Serum creatinine (SCr) was 0.59 mg/dl. Anti-proteinase 3 titers were positive (1:160). Urine studies showed microhematuria and low-grade proteinuria with a urine protein:creatinine ratio (UPC) of 0.85. A kidney biopsy showed pauci-immune focal necrotizing glomerulonephritis, consistent with ANCA-associated vasculitis. Corticosteroids and rituximab were initiated by nephrology. A month later, SCr increased to 2.86 mg/dl. She developed severe headaches, periorbital edema, and vision changes, leading to the diagnosis of dacryocystitis. A lacrimal gland biopsy showed marked acute inflammation due to histiocytosis, plasma cells, and lymphocytes. Pulse steroids and rituximab were re-administered, followed by steroid tapering per the PEXIVAS protocol and the addition of avacopan. Though renal function improved, she had worsening orbital symptoms. She received another cycle of pulse-dose steroids and two doses of cyclophosphamide, with improvement in eye and nasal symptoms. At her most recent visit, SCr was 0.86 mg/dl and UPC was 0.45. Continued immunosuppression with rituximab for 18–24 months, along with avacopan, was planned. Discussion: A multidisciplinary team including nephrology, rheumatology, pulmonology, and ophthalmology managed the patient. The nephrologist played a crucial role in diagnosing the disease with a renal biopsy (performed when normal renal function and only mild abnormalities in urine were present) and initiating immunosuppression. Successful management of this complex case exemplifies the invaluable contribution of the nephrologist as part of the interdisciplinary team navigating the challenges posed by systemic GPA.