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Kidney Week

Abstract: TH-PO554

IgG4 Nephritis, When Rising Creatinine Is Not a Progression of CKD

Session Information

  • Trainee Case Reports - I
    October 25, 2018 | Location: Exhibit Hall, San Diego Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Trainee Case Reports

  • 1902 CKD (Non-Dialysis): Clinical, Outcomes, and Trials

Author

  • Kruger gomes, Larissa, University of Connecticut Internal Medicine residency, Farmington, Connecticut, United States
Introduction

Immunoglobulin G4 (IgG4) is a rare disease with a diagnosis dependent on high clinical suspicion, specially when a single organ is affected. We present a case of IgG4 tubulointerstitial nephritis (TIN) and discuss when to suspect this disorder.

Case Description

A 64-year-old male with history of type 1 diabetes and chronic kidney disease with a creatinine (Cr) baseline of 1.2mg/dL, was referred to clinc after having an increase of Cr to 3.3mg/dL over 4 months. There were no recent changes in medications or sickness. Blood pressure and diabetes were under control with an HBA1C of 7.3% and microalbuminuria of 33mcg. Urinalysis (UA) showed 2-4 red blood cells and a protein/cr ratio of 800mg/g. Due to the unlikelihood of rapid progression of diabetic nephropathy, investigation for acute kidney injury with serology and renal ultrasound were pursued. Results were significant for low C3 and C4 and a rising Cr of 3.5mg/dL. Consequently, a kidney biopsy was done, revealling diffuse TIN with a dense plasma cell infiltrate with a high proportion of IgG4 cells and tubular basement membrane immunocomplex deposits. IgG4 levels were 683.5 mg/dL. With the diagnosis of IgG4 TIN, patient was started on prednisone 40 mg daily. After 1 month, the patient’s Cr was 2.3mg/dL and after 4 months, 1.9mg/dL with IgG4 levels of 118 mg/dL. Patient is currently off prednisone and is being monitored for recurrence.

Discussion

IgG4-related kidney disease has higher prevalence among older men and it is usually related to extra renal disease, with sole renal impairment in 2-12% of cases. The pattern of intrinsic disease is most commonly TIN but can also be membranous. Patients can present with worsening of baseline CKD, making it important to add IgG4 disease in your differential. Igg4 disease should be suspected in patients with rising Cr and signs of tubular injury, but no white blood cells on UA neither obvious pharmacological or infectious etiology. Low complement levels and normal ESR/CRP are suggestive of IgG4 disease, however, to fit the diagnosis, biopsy findings of TIN with >10 igG4positive plasma cells/hpf in addition to one of the clinical criteria of elevated igG4 and igG levels, specific imaging findings or extra renal disease must be present. Steroids are first line treatment and remission is achieved in 82% of cases. Rituximab is indicated in refractory cases. Patients with higher GFRs tend to respond well to treatment.