Abstract: PO0313
Unexplained AKI: Never "Brush" Off the Role of a Renal Biopsy
Session Information
- AKI: Clinical Case Reports
November 04, 2021 | Location: On-Demand, Virtual Only
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 103 AKI: Mechanisms
Authors
- Shah, Chintav, University of Arkansas for Medical Sciences, Fayetteville, Arkansas, United States
- Rodby, Roger A., Rush University Medical Center, Chicago, Illinois, United States
- Ghaffar, Umbar, University of Arkansas for Medical Sciences, Fayetteville, Arkansas, United States
Introduction
Anti-Brush Border Antibody Disease (ABBAD) is a rare condition typically seen in elderly individuals and presents with acute kidney injury (AKI) and sub-nephrotic proteinuria. Patients often progress rapidly to ESKD despite treatment.
Case Description
A 73-y/o man with a PMH of HTN, a-fib and CKD (serum creatinine SCr 1.5 mg/dl 4 mo ago and 2.3 mg/dl 2 mo ago) was found to have a SCr of 3.2 mg/dl. His medications were tamsulosin, apixaban, losartan and metoprolol tartrate. He denied NSAID usage. His vital signs were normal and his physical exam was unremarkable. His urinalysis was significant for 2+ protein without blood. He had an elevated urine protein/Cr ratio at 1.5 g/g. Serological and infectious workups were negative. A renal ultrasound was normal. A renal biopsy demonstrated 50% global sclerosis with remaining glomeruli normal. There was moderate interstitial fibrosis and tubular atrophy. The immunofluorescence and electron micrographs are shown in Fig 1a and 1b. Specific IF staining for lipoprotein-related protein 2 (LRP2) was positive in the tubular basement membrane (TBM), consistent with a diagnosis of ABBAD. Because of his advanced age he was treated with 60 mg of prednisone alone with no improvement.
Discussion
ABBAD occurs from formation of IgG antibodies against low density lipoprotein-related protein 2 (LRP2) megalin which deposit on the tubular BM of the PCT. Because it is so rare, (<20 cases) little is known about the treatment with rare responses to prednisone and cytotoxic agents. It is unknown if rituximab is effective. ABBAD can recur in a renal transplant. Early diagnosis and aggressive immunotherapy would seem prudent. This approach requires a low renal threshold for biopsy in AKI. It is however unknown if early treatment can alter the typical abysmal renal outcome.
1a) IF showing segmental staining with IgG along the tubular basement membrane.
1b) EM showing electron dense deposits along the tubular basement membrane.