A Case of Severe Hypocalcemia Caused by Malabsorption Due to Partial Gastrectomy and Small Bowel Resection

• Type of Material: Article
• Authors: John O. Knight, Emory University; Lucia F. Cotten, Emory University; Thomas Ziegler, Emory University; Priyathama Vellanki, Emory University
• Language: English
• Date: 2021-09-01
• Publisher: Elsevier
• Publication Version: Final Published Version
• Copyright Statement: © 2021 AACE. Published by Elsevier Inc.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.aace.2021.04.002
• Title of Journal or Parent Work: AACE Clinical Case Reports
• Volume: 7
• Issue: 5
• Start Page: 323
• End Page: 326
• Grant/Funding Information: P.V. is supported in part by NIH/NIDDK K23 DK11324-01A1. The other authors have no multiplicity of interest to disclose.
• Keywords: ECF, extracellular fluid; D[1,25(OH)2D], 1,25-hydroxy vitamin D; PTH, parathyroid hormone; achlorhydria; D[25(OH)D], 25-hydroxy vitamin D; malabsorption; hypocalcemia; small bowel resection; gastrectomy
• Research Categories: Health Sciences, Nutrition; Biology, Microbiology

Abstract

Objective: Calcium is an essential mineral involved in the functioning of nearly every human cell. Calcium levels are regulated by dietary absorption, vitamin D status, and parathyroid hormone (PTH). This report describes a patient in whom childhood bowel resection and partial gastrectomy resulted in malabsorptive hypocalcemia in adulthood. Case Report: A 21-year-old man presented with syncope and a fall resulting in a right femoral neck fracture. His medical history included small bowel obstructions at age 9 requiring bowel resection, and at age 12 with gastric perforation and partial gastrectomy. Laboratory values showed calcium level of 4.9 mg/dL (8.9-10.3 mg/dL). PTH level was 273 pg/mL (12.0-88.0 pg/mL), 25-hydroxy-vitamin D was 28 ng/dL (30-100 ng/mL), and 1,25-dihydroxy-vitamin D was 54 pg/dL (18-72 pg/mL). Furthermore, magnesium and phosphorus levels were 2.1 mg/dL (1.5-2.6 mg/dL) and 4.4 mg/dL (2.4-4.7 mg/dL), respectively. Calcium levels improved to 9.5 mg/dL on 10% calcium gluconate drip but could not be maintained above 7 mg/dL on oral calcium carbonate supplementation, despite doses as high as 3750 mg three times daily with calcitriol 0.75 mcg twice daily. After switching from calcium carbonate to calcium citrate 3500 mg three times daily, the calcium level improved and was maintained between 8.3 and 9.0 mg/dL. Discussion: High calcium needs, other nutrient deficiencies, and response to calcium citrate versus calcium carbonate suggest malabsorption from achlorhydria and small bowel resection. Conclusion: This case emphasizes the gastrointestinal physiology in calcium homeostasis and highlights the recognition of hypocalcemia as a complication of gastric and bowel resection.