Abstract: FR-PO833
Diet-Induced Oxalate Nephropathy: Eating Too Much "Healthy" Food
Session Information
- Health Maintenance, Nutrition, Metabolism - II
November 03, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Health Maintenance, Nutrition, and Metabolism
- 1500 Health Maintenance, Nutrition, and Metabolism
Authors
- Landry, Alexander Pete, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Triozzi, Jefferson Lorenzo, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Fogo, Agnes B., Vanderbilt University Medical Center, Nashville, Tennessee, United States
- McCall, Natalie Nesmith, Vanderbilt University Medical Center, Nashville, Tennessee, United States
Introduction
Oxalate nephropathy is an intrinsic kidney disease characterized by kidney tubular injury via the deposition of calcium oxalate crystals with initial acute tubular injury that can progress to scarring and eventually to end-stage kidney disease. This condition may be caused by primary hyperoxaluria (genetic), enteric hyperoxaluria (in the setting of fat malabsorption), and ingestions (foods high in oxalate, ethylene glycol toxicity). We present a case of "healthy" diet-induced oxalate nephropathy.
Case Description
A 57-year-old man with type II diabetes mellitus, hypertension, urinary retention requiring indwelling urinary catheterization, and psychiatric comorbidities including obsessive compulsive disorder presented to nephrology clinic with acute kidney injury. He reported a diet consisting of obsessive compulsive eating behavior. He reported heavy ingestion of foods presumed to be healthy, including oranges, assorted nuts, turkey, and up to 5 protein bars at a time. Vital signs and physical exam were unremarkable. Serum creatinine was 2.1 mg/dL (baseline 1.2 mg/dL) with a bland urinalysis without hematuria or proteinuria. Serologic work-up was unremarkable. A kidney biopsy revealed numerous calcium oxalate crystals associated with diffuse acute tubular injury, diagnostic of oxalate nephropathy.
Discussion
Oxalate nephropathy is an intrinsic kidney disease characterized by deposition of calcium oxalate crystals in the kidney tubules. Excessive consumption of foods high in oxalate or its precursors can cause acute or chronic kidney disease. In this case, the ingestion of oranges, nuts, turkey slices, and protein bars may have led to oxalate nephropathy. Vitamin C (ascorbic acid) found in citrus fruits is a precursor to oxalate. However, vitamin C supplementation is more commonly reported as a cause because it is more bioavailable. Nuts are also a high oxalate food, with almonds, Brazil nuts, and pine nuts holding the highest oxalate content. Finally, high protein intake may increase oxalate excretion in the urine. Patients with acute oxalate nephropathy typically recover kidney function and have a better prognosis than those with chronic disease. In this case, the patient reduced his intake of high oxalate foods and increased fluid intake to 2 liters of water daily. Thereafter he had progressive improvement of kidney function back to baseline.