Severe Renal Impairment in a Patient with Recent Rheumatoid Arthritis Diagnosis following Methotrexate Initiation: A Case Report.

Rheumatoid arthritis (RA) is a chronic autoimmune disease frequently treated with immunosuppressive agents such as methotrexate (MTX). Although MTX is generally well-tolerated, it can lead to adverse effects, including renal impairment. We present a case of a patient with newly diagnosed RA who developed severe renal impairment shortly after initiating MTX therapy. A 50-year-old male with recently diagnosed RA presented with vomiting, skin itching, mouth ulcers, and a pruritic rash, all occurring shortly after starting MTX treatment. These symptoms led to acute kidney injury (AKI), necessitating hemodialysis. The patient's symptoms and laboratory findings were indicative of ANCA-associated small-vessel vasculitis with a picture of rapidly progressive glomerulonephritis (RPGN). Treatment included discontinuation of MTX, hemodialysis, immunosuppressive therapy with corticosteroids and cyclophosphamide, and patient education. This case emphasizes the need for close monitoring of RA patients initiated on MTX therapy and prompt evaluation of renal function. Clinicians should be vigilant for signs of renal impairment and be prepared to initiate appropriate interventions, including discontinuation of MTX and consideration of immunosuppressive therapy, to optimize patient outcomes. Further research is warranted to understand better the mechanisms underlying renal complications in RA patients receiving MTX treatment.