Abstract: PUB208
Rare Coexistence of Membranous Nephropathy and Interstitial Nephritis in Renal Sarcoidosis Without Proteinuria
Session Information
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Aslam, Ahsan, Indiana University School of Medicine, Indianapolis, Indiana, United States
- Safdar, Faryal, Indiana University Indianapolis Richard M Fairbanks School of Public Health, Indianapolis, Indiana, United States
- Guo, Shunhua, Indiana University School of Medicine, Indianapolis, Indiana, United States
Introduction
Renal disease is an uncommon presentation of sarcoidosis. When present,the most common renal manifestation is abnormal serum creatinine and pyuria: diagnostic of tubulointersitial nephritis. Glomerular disease usually presents with proteinuria, with secondary membranous nephropathy being the most common.
Case Description
A 46-year-old African American woman with a history non-Hodgkin lymphoma and CVID was seen in the office for abnormal serum creatinine. Over the preceding 11 months, her serum creatinine had progressively increased from a baseline of 0.91 mg/dL to 1.71 mg/dL. This was accompanied by sterile pyuria, indicated by 11-20 white blood cells in her urine.There was no proteinuria.
A kidney biopsy was performed to investigate these findings. Biopsy revealed diffuse non-necrotizing granulomatous inflammation within the interstitium, along with moderate tubular atrophy and interstitial fibrosis. Additionally, immunofluorescence showed granular deposits of IgG, C3, kappa, and lambda light chains in the glomerular capillary walls. Electron microscopy further identified scattered subepithelial electron-dense deposits, consistent with early-stage membranous nephropathy. Notably, testing for PLA2R antibodies in biopsy and serum was negative and patient was deemed to have secondary MN.
She was previously evaluated by pulmonology for an elevated Angtiotensin converting enzyme (ACE) level and her CT chest did not show any evidence of sarcoidosis.Given these findings, a diagnosis of renal sarcoidosis was established.She was started on high-dose prednisone (60 mg daily) for 2 months, followed by a taper . Her repeat urine analysis by 4 weeks showed resolution of pyuria and her serum creatinine stabilized at 1.78 mg/dL.
Discussion
Our case highlights that findings of a secondary MN can rarely be seen in the absence of overt proteinuria in sarcoidosis involving the kidney.It also shows that an elevated ACE level could predate the development of an overt renal sarcoidosis.