Association of Granulomatosis with Polyangiitis and Rheumatoid Arthritis: A Rare Overlap Syndrome

Background: Granulomatosis with polyangiitis (GPA) is a type of antineutrophilic cytoplasmic antibodies (ANCA) associated vasculitis that primarily involves upper respiratory tract, lungs and kidneys. It is a rare disease and its association with rheumatoid arthritis is even rarer. Early recognition of such overlaps enables more timely diagnosis and may have impact on disease outcome. Case presentation: Here we report a case of 29-year-old female, known case of rheumatoid arthritis (RA) since 2019, presented in February 2023 with complaint of fever and cough for 20 days. On evaluation, patient was having deranged renal function tests. Chest Xray revealed multiple thick wall cavities and nasal cavity examination showed thick crusting. Based on these findings GPA was suspected and antineutrophilic cytoplasmic antibodies directed against proteinase 3 (PR3 ANCA) levels and kidney biopsy was planned. PR3 ANCA levels were raised and kidney biopsy revealed pauci-immune glomerulonephritis. In view of RPGN rituximab therapy was started along with prednisolone. Conclusion: ANCA associated vasculitis (AAV) associated with RA may be a rare form of an AAV autoimmune overlap. Its recognition can lead to timely antibody screening of patients with the relevant clinical scenario and a more rapid initiation of appropriate management.