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Kidney Week

Abstract: SA-PO858

Monoclonal Gammopathy of Renal Significance Presenting as Cryoglobulinemic Glomerulonephritis

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: From Inflammation to Fibrosis

Authors

  • Botros, Shirley, Albany Medical College, Albany, New York, United States
  • Aydin-Ghormoz, Emmanuel Albert, Albany Medical College, Albany, New York, United States
  • Mehta, Swati, Albany Medical College, Albany, New York, United States
  • Hongalgi, Krishnakumar D., Albany Medical College, Albany, New York, United States
Introduction

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant plasma cell disorder characterized by serum monoclonal protein <3g/dL, clonal plasma cells <10% on bone marrow biopsy, and absence of end-organ damage. Treatment is not recommended. When monoclonal immunoglobulin causes kidney damage, monoclonal gammopathy of renal significance (MGRS) is diagnosed and treatment involves chemotherapy. We describe a patient with known MGUS presenting with AKI and cryoglobulinemic glomerulonephritis (CG) secondary to development of MGRS.

Case Description

A 73 year-old-man with CKD stage 3, type 2 DM, chronic microscopic hematuria, and MGUS presented with AKI. Previous CKD workup showed 0.5g/day proteinuria, positive ANA, low C4, positive rheumatoid factor, and negative dsDNA and ANCAs. He had elevated free kappa light chains on SPEP and bone marrow biopsy confirmed IgM MGUS. CKD and proteinuria were attributed to diabetic kidney disease. Work-up of chronic hematuria was unrevealing. He presented 8 month later with fatigue, dyspnea, epistaxis, lower extremity rash, and hematuria with Cr 2.2 mg/dL (baseline 1.7) and 24 hour urine protein 3.5g. Serology was positive for cryoglobulin and negative for Hepatitis B, C, and HIV. Kidney biopsy showed diffuse, focally crescentic mixed cryoglobulinemic glomerulonephritis, likely type II, with focal leukocytoclastic vasculitis, focal severe arteriosclerosis, and moderate to severe interstitial fibrosis and tubular atrophy. He underwent 5 sessions of plasmapheresis, IV rituximab, and induction with oral steroids. Symptoms resolved and Cr improved to 1.9 mg/dL at discharge. He continued steroid taper, rituximab, and started IVIG. At last follow-up, he had full resolution of symptoms with stable Cr of 1.8 mg/dL.

Discussion

This case describes a patient with known MGUS presenting with AKI and CG secondary to MGRS. Treatment was rapidly initiated with improvement in kidney function. CG can be caused by a variety of infections, autoimmune diseases, and hematologic malignancies. Identification of the underlying cause is important and guides treatment. Prompt nephrology referral and biopsy in MGUS patients with elevated creatinine, proteinuria, and hematuria allows for diagnosis of MGRS and initiation of therapy to preserve kidney function, avoid long term dialysis, and reduce mortality.