Abstract: TH-PO649

Acute Interstitial Nephritis in the Setting of Fibrillary Glomerulonephritis: Case Report and Review of Literature

Session Information

Category: Nephrology Education

  • 1302 Fellows and Residents Case Reports

Authors

  • Suvarnasuddhi, Khetisuda, Brown University , Providence, Rhode Island, United States
  • Sharif, Sairah, Brown University , Providence, Rhode Island, United States
Background

Fibrillary glomerulonephritis (FGN) is a rare primary glomerular disease that presents with hypertension, proteinuria, microscopic hematuria and variable renal failure. It is often associated with hepatitis C virus (HCV). We report a case of FGN along with acute interstitial nephritis (AIN) in patient with HCV who had response to therapy.

Methods

A 61 year old Caucasian male with past history HCV (viral load PCR 979330IU/ml), HTN, chronic kidney disease (baseline creatinine (Cr) 1.2 mg/dL), and hemorrhagic stroke presented for evaluation of hypotension and fatigue. He was found to have urinary tract infection secondary to Proteus and Enterococcus started on piperacillin/tazobactam; later de-escalated to amoxicillin/clavulanate. Course complicated by acute kidney injury (AKI). Initial etiology of AKI thought to be pre-renal azotemia from poor oral intake and ischemia from hypotension. Urine sediment revealed few muddy brown casts, WBCs> 100/HPF, RBCs >100/HPF, and few dysmorphic RBCs. Serologies were negative for autoimmune diseases, and C3 and C4 were normal. Renal ultrasound showed increased echogenicity of renal cortex; and no hydronephrosis. AKI worsened and Cr peaked at 4.3mg/dL. Due to worsening AKI renal biopsy was performed that showed on light microscopy (LM) mesangial expansion, interstitial nephritis, mild interstitial fibrosis and tubular atrophy, electron microscopy (EM) demonstrated numerous random fibrils average 15nm identified as FGN. Patient was started on steroids for interstitial nephritis, and plan to start outpatient HCV therapy. His SCr improved to 1.7 in about 2 weeks from steroid initiation.

Conclusion

FGN is found in about 1% renal biopsies. It typically presents in the fifth to sixth decade. There maybe background of HCV, polyclonal gammopathy, and/ or lymphoproliferative disorders. The LM is heterogenous usually membranoproliferative, or mesangioproliferative, or diffuse proliferative GN. EM (EM) shows randomly oriented fibrils about 20nm in diameter. Optimal therapy is not known but corticosteroids and immunosuppressants have been tried with little success. About half of patients progress to dialysis. To the best of our knowledge this is the first case of FGN with AIN reported that showed response to corticosteroids.