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Kidney Week

Abstract: PO0314

Vitamin C, CKD, and Roux-en-Y; A Dangerous Combination

Session Information

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Schmidt, Darren W., University of New Mexico School of Medicine, Albuquerque, New Mexico, United States
  • Messias, Nidia Cordeiro, Arkana, Little Rock, Arkansas, United States
  • Shaffi, Saeed Kamran, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States
Introduction

Patients who have undergone bariatric procedures can be at increased risk for acute kidney injury (AKI) due to oxalate nephropathy; therefore, it is important that there is an awareness of other risk factors for this condition in this patient population. In particular, high doses of vitamin C should be avoided.

Case Description

A 74-year-old female, who had a Cr of 0.8 mg/dl a year prior, with a history of Roux-en-Y gastric bypass surgery in 2016, recurrent nephrolithiasis, and an atrophic right kidney was advised to go to the hospital after outpatient laboratory data revealed a Cr of 8.7 mg/dl. The patient had been taking Vitamin C 1000 mg daily. An initial evaluation did not reveal an etiology of AKI and her renal function did not improve with 48 hours of IV fluids. Hemodialysis was initiated for uremic symptoms. The patient underwent a biopsy (Figure 1) which showed severe acute tubular injury, mild interstitial fibrosis and tubular atrophy, and significant tubular calcium oxalate crystal deposition. At the time of discharge, she had poor creatinine clearance and remained on hemodialysis.

Discussion

AKI related to oxalate nephropathy can be viewed as a confluence of pre-disposing conditions, risk factors, and exposures. Any single case may have one or more of these issues; this case is remarkable in that it encompasses multiple factors: 1. A pre-existent history of calcium oxalate stones, 2. A markedly atrophic right kidney, with a suspicion of chronic kidney disease and a reduced excretory capacity, 3. Prior Roux-en-Y gastric bypass resulting in increased absorption of oxalate, 4. Supplemental vitamin C intake, 5. Pyridoxine deficiency which limits the body’s ability to “detoxify” oxalate. Unfortunately, oxalate nephropathy is associated with poor renal outcomes; therefore, patients with multiple risk factors for this condition should be appropriately counseled and closely monitored.

Figure 1: H & E stain