A Rare Case of Acute Kidney Injury (AKI) WIth IGG-4 Related Disease (RD) Without Extra Renal Manifestations

Document Type

Conference Proceeding

Publication Date

4-2023

Publication Title

American Journal of Kidney Diseases

Abstract

Immunoglobulin G4 (IgG4) RD is an immune-mediated, inflammatory disease that can commonly involve the biliary and gastrointestinal organ systems1. The epidemiology is unknown with a predisposition in males2. Here we describe a rare case of IgG4 RD causing isolated AKI. A 70-year-old male with chronic kidney disease stage 3 secondary to type 1 diabetic nephropathy, hypertension, benign prostate hyperplasia, and coronary artery disease presented to the hospital. He was referred by his cardiologist due to elevated creatinine (Cr) of 6.24 mg/dL from a baseline of 1.4 mg/dL, with no improvement on repeat testing after discontinuing lisinopril and hydrochlorothiazide. He was admitted for further workup which revealed mild anemia, uremia of 86 mmol/L, serum bicarbonate, and potassium of 16 and 5.3 mmol/L respectively. Urine analysis showed ketonuria and proteinuria with no hematuria or casts. The urinary albumin to Cr ratio and complement C4 levels were low but C3 was normal. Autoimmune workup was negative. Renal ultrasound showed no hydronephrosis or renal calculus. This, including no improvement in Cr with foley catheter placement, ruled out post-renal cause. A failed trial of volume resuscitation ruled out pre-renal cause. Serum protein electrophoresis revealed a polyclonal increase in IgG4 with levels >300mg/dL. Renal biopsy revealed tubulointerstitial inflammation and increased IgG4 positive plasma cells (>20/high power field) which confirmed the diagnosis. He received a trial of intravenous furosemide for oliguria and was started on intermittent hemodialysis (IHD) for symptomatic uremia and volume overload. After diagnosis confirmation, he was started on 50 mg of prednisone daily for 4 weeks, which was tapered, and IHD thrice weekly outpatient until kidney function recovered. IgG4 RD nephropathy presents as an acute decline in kidney function, without any reversible cause or inciting factor. Elevated serum IgG4 levels should prompt further workup with a kidney biopsy even in the absence of extrarenal involvement3. Management includes supportive treatment and long-term steroids with close monitoring. Physicians should identify IgG4 disease based on serology, histology and radiological findings, even when there is no evidence of extrarenal disease

Volume

81

Issue

4(Suppl. 1)

First Page

S12

Comments

National Kidney Foundation Spring Clinical Meeting, April 11-15, 2023, Austin, TX

DOI

10.1053/j.ajkd.2023.01.043

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