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Kidney Week

Abstract: SA-PO056

What to Do When It RAINs?

Session Information

Category: Acute Kidney Injury

  • 102 AKI: Clinical, Outcomes, and Trials

Authors

  • Upadrista, Pratap Kumar, Northwell Health, New Hyde Park, New York, United States
  • Sharma, Purva D., Northwell Health, New Hyde Park, New York, United States
Introduction

Recurrent Acute Interstitial Nephritis (RAIN) is a poorly studied condition, associated with adverse kidney outcomes. Treatment options for RAIN are not well established, making management more challenging. Systematic approach for ruling out underlying causes and prompt diagnosis and treatment are of paramount importance to salvage kidneys. However, no precise cause can be identified in many cases. Here, we present a case of idiopathic RAIN that was successfully treated with MMF.

Case Description

A 70 Y/O F with Hx of DM, HTN, HLD came to ED with fever of ~ 2 weeks, low back ache, chills, and malaise. She was on Metformin, Losartan, HCTZ and Omeprazole. Physical examination was unremarkable. On presentation, she had anemia (Hb 9.8 gm/dL), AKI with a Scr of 4.0 mg/dL (baseline Scr 6 weeks ago was 0.9 mg/dl) and BUN of 40mg/dL. UPCR was 0.6 g/g. Blood & urine cultures were negative. Hepatitis B & C serologies were negative and SPEP was normal. A kidney biopsy was suggestive of AIN, presumed to be due to PPI. Omeprazole was stopped and she was started on prednisone 1mg/kg/day (80mg/d), her creatinine started to improve with a nadir of 1.6 mg/dl and prednisone was slowly tapered off over 2 months. Off prednisone, for a month, her creatinine worsened to 2.75 mg/dL. Other causes of AKI were ruled out, and she was restarted on prednisone at 0.75mg/kg/d for AIN recurrence. Creatinine improved to 1.25mg/dL and prednisone tapered off. However, 3 weeks later, she again developed AKI (Scr 1.6mg/dL). Due to 2nd recurrence of AIN, we looked for systemic disorders. IgG, ANA, ENA profile & ANCA were negative. CT chest and abdomen was negative for malignancy. Repeat protein electrophoresis, FLC ratio were normal. PET-CT ruled out any inflammation. She was started on MMF 500mg BID as steroid sparing agent for idiopathic recurrent AIN. Her creatinine stabilized at 1.26 mg/dL and repeat UA was negative for proteinuria and hematuria. She has remained stable for the last 9 months on this regimen.

Discussion

RAIN needs thorough work up. Its management options are not standardized. MMF, Azathioprine, CNI and Rituximab have been tried with some success. Biomarkers to diagnose and prognosticate AIN like CXCL-9, TNF-α, IL-9 are under consideration. We aim to highlight the management of idiopathic RAIN with MMF as steroid sparing agent with good outcome. We need more studies to establish guidelines to effectively manage this entity.