Kidney Week

Abstract: FR-PO697

Calcium Maldistribution: A Case of Calcium Nephrolithiasis, Aortic Calcification, and Osteopenia

Session Information

• Electrolytes and Cancer Trainee Case Reports
  November 08, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Trainee Case Report

• 402 Bone and Mineral Metabolism: Clinical

Authors

• Dalsan, Rochelle, Albert Einstein College of Medicine/Montefiore Medical Center , Bronx, New York, United States

Rochelle Dalsan,

• Sharma, Deep, Albert Einstein College of Medicine/Montefiore Medical Center , Bronx, New York, United States

Deep Sharma,

• Stern, Joshua M., Albert Einstein College of Medicine/Montefiore Medical Center , Bronx, New York, United States

Joshua M. Stern,

• Epstein, Eric J., Albert Einstein College of Medicine/Montefiore Medical Center , Bronx, New York, United States

Eric J. Epstein,

• Bushinsky, David A., University of Rochester School of Medicine and Dentistry, Rochester, New York, United States

David A. Bushinsky,

• Chen, Wei, Albert Einstein College of Medicine/Montefiore Medical Center , Bronx, New York, United States

Wei Chen,

Introduction

Epidemiologic studies show that patients with nephrolithiasis have a higher prevalence of aortic calcification and bone demineralization compared to those without nephrolithiasis. We present a case of calcium nephrolithiasis with concomitant aortic calcification and osteopenia.

Case Description

A 62-year-old post-menopausal woman was seen for evaluation of nephrolithiasis. She was a smoker, but had no significant past medical history. Work up revealed serum K 4.8 mEq/L, CO₂ 26 mEq/L, creatinine 0.8 mg/dL, calcium 9.6 mg/dL, phosphorous 3.9 mg/dL, intact parathyroid hormone 31 pg/mL, 25-hydroxy vitamin D 42 ng/mL and urinary pH ≥6.2 on all urinalyses (n=4), suggesting possible incomplete renal tubular acidosis. Stone analysis showed 100% calcium phosphate. Urine supersaturation showed marked hypocitraturia (235 mg/day) without hypercalciuria (153 mg/day). On computed tomography, she had numerous right kidney stones and significant abdominal aortic calcification [figure]. Dietary history revealed low calcium intake. Dual-energy x-ray absorptiometry (DEXA) was performed and showed osteopenia in the lumbar spine (T score: -2.3, Z-score: -0.7) and left femoral neck (T score: -1.4, Z-score: -0.2). As per Fracture Risk Assessment Tool, her 10-year fracture risk for a major osteoporotic fracture was 8.4%. Given above findings, we recommended smoking cessation, increasing dietary intake of calcium, fruits and vegetables, and to continue monitoring bone density.

Discussion

This is a case of calcium maldistribution, in which there was extraosseous deposition of calcium in the right kidney and aorta, and bone demineralization. The presence of nephrolithiasis and arterial calcification prompted us to perform a DEXA scan, which led to a more comprehensive treatment plan. More importantly, the case highlights an important need to better understand the pathophysiology underlying the maldistribution and extraosseous deposition of calcium.