Abstract: TH-PO643

A Case of Rapidly Progressive Glomerulonephritis Secondary to Monoclonal Gammopathy

Session Information

Category: Nephrology Education

  • 1302 Fellows and Residents Case Reports

Authors

  • Beltran Melgarejo, Diego Andres, Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Al-Sheyyab, Ahmed, Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Sanghani, Neil S., Vanderbilt University Medical Center, Nashville, Tennessee, United States
Background

Proliferative glomerulonephritis with monoclonal IgG deposition (PGNMID) is characterized by monoclonal glomerular deposits staining for a single light-chain isotype and a single heavy-chain subclass. It is more common in white female adults and usually presents with hematuria, nephrotic range proteinuria, and renal failure. Evidence of dysproteinemia is seen in only ~30% of the cases.

Methods

A 74 y/o Caucasian man with history of hypertension presented with a rash and rapidly progressive glomerulonephritis (RPGN). Physical exam revealed severe hypertension, trace lower extremity edema, and a non-blanching purpuric rash in all 4 extremities. The rest of his exam was normal.
Lab results showed a serum creatinine (SCr) of 4.5 mg/dl (baseline 1 mg/dl), hematuria, and nephrotic range proteinuria. C3 and C4 were normal. There was no hemolysis or thrombocytopenia. ANA, AntiDNA, ANCA, antiGBMAb, cryoglobulins, and HCV/HBV/HIV serologies, were negative. Immunofixation electrophoresis did not show a monoclonal protein in the serum or urine. Kappa (κ) and lambda (λ) serum light chains were mildly elevated but κ/λ ratio was normal. Skin biopsy demonstrated superficial perivascular dermatitis suggestive of a drug eruption or urticaria.
Renal biopsy revealed endocapillary proliferation, cellular crescents, and fibrinoid necrosis. There was granular mesangial and pseudo-linear capillary loop staining by IF with monoclonal IgG λ (2-3+), C3 (3+) and C1q (1-2+), IgG3 (3+) and IgG4 (1-2+), with trace IgG1 and IgG2. Subendothelial and mesangial deposits without specific substructure were seen on EM.
Pulse steroids resulted in stabilization of SCr and resolution of skin rash, but were discontinued due to delirium. Rituximab was started with further improvement in SCr to 3.7mg/dl.

Conclusion

PGNMID is a monoclonal gammopathy that resembles an immune-complex GN. This case highlights RPGN and possibly skin involvement as atypical presentations of this condition. Renal biopsy with particular attention to light chain and IgG subclass restriction is key to confirm the diagnosis. Though no treatment guidelines are available, the severity of renal involvement might guide immunosuppressive choice. Pulse steroids and rituximab could be a potential effective treatment for this pathology.