Calcium Mediates the Phosphaturia in Hypercalcemia of Malignancy

Issac Sachmechi, Veronica Jedlovsky, George Schussler

Abstract


Background: Humoral hypercalcemia of malignancy (HHM) is claimed to be caused by circulating parathyroid hormone like peptide (PTHrP) that shares several of the cardinal biochemical and skeletal histological features with hyperparathyroidism (HPT). Both syndromes are characterized by hypercalcemia from increased renal tubular reabsorption of filtered calcium, increased urinary cyclic AMP, renal phosphate wasting and hypophosphatemia, in contrast to low 1,25(OH)2D levels, metabolic alkalosis, and uncoupled bone formation-resorption rate in HHM. The aim of the study was to reassess if phosphaturia of HHM can be attributed to hypercalcemia rather than to humoral effect of PTHrP.

Methods: A prospective study was conducted at Mount Sinai Services at Queens Hospital Center, NY.

Results: Nine (four females and five males) out of 20 patients with hypercalcemia of malignancy documented having elevated PTHrP, normal renal function, and low PTH levels were finalized for the study. Serum calcium, phosphate, creatinine, albumin, and PTHrP concentration were determined. On the initiation of hydration, 24 h urine for creatinine, calcium and phosphorous were also collected. Blood and urine tests were repeated after serum calcium levels had been decreased by at least 1.5 mg/dL. All patients received vigorous intravenous hydration with normal saline at 200 cc/h. After the first 24 h, small doses of furosemide were given to two out of nine patients for 48 - 72 h. Hydration has shown statistically significant decrease in serum calcium concentration (13.9 ± 2.1 to 10.8 ± 1.48 mg/dL; P < 0.001) and increase in tubular reabsorption of phosphate (TRP) (69.54±8.16% to 77.85±12.24%; P < 0.01). However, PTHrP levels have shown no statistically significant difference on hydration therapy.

Conclusion: Improvement of hypercalcemia by hydration reverses phosphaturia without reducing PTHrP levels. It is being proposed that in HHM, PTHrP can lead to hypercalcemia from uncoupled bone formation-resorption rate through a local autocrine or paracrine action produced by bony micrometastases that could not be demonstrated radiologically, rather than from PTHrP’s humoral effect.




J Endocrinol Metab. 2017;7(2):55-60
doi: https://doi.org/10.14740/jem402w

 


Keywords


Hypercalcemia of malignancy; Parathyroid hormone like peptide; Phosphaturia; Tubular reabsorption of phosphate

Full Text: HTML PDF
 
Home     |     Log In     |      About     |      Search     |      Current     |      Archives     |      Submit      |     Subscribe


 

     

Aims and Scope

Current Issues

Conflict of Interest

About Publisher

Editorial Board

Archives

Copyright

Company Profile

Editorial Office

Misconduct and Retraction

Permissions

Company Registration

Contact Us

Abstracting and Indexing

ICMJE

Ownership

Instructions to Authors

Access

Declaration of Helsinki

Contact Publisher

Submission Checklist

Reprints

Terms of Use

Company Address

Submit a Manuscript

Open Access Policy

Privacy Policy

Browse Journals

Publishing Fee

Publishing Policy

Disclaimer

Recent Highlights

Peer-Review Process

Publishing Quality

Code of Ethics

Advertising Policy

Manuscript Tracking

Advanced Search

For Librarians

Careers

Publishing Process

Publication Frequency

For Reviewers

Propose a New Journal

       
       

Journal of Endocrinology and Metabolism, bimonthly, ISSN 1923-2861 (print), 1923-287X (online), published by Elmer Press Inc.     
The content of this site is intended for health care professionals.
This is an open-access journal distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License, which permits unrestricted
non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Creative Commons Attribution license (Attribution-NonCommercial 4.0 International CC-BY-NC 4.0)


This journal follows the International Committee of Medical Journal Editors (ICMJE) recommendations for manuscripts submitted to biomedical journals,
the Committee on Publication Ethics (COPE) guidelines, and the Principles of Transparency and Best Practice in Scholarly Publishing.

website: www.jofem.org   editorial contact: editor@jofem.org
Address: 9225 Leslie Street, Suite 201, Richmond Hill, Ontario, L4B 3H6, Canada

© Elmer Press Inc. All Rights Reserved.

DECLARATION: THIS JOURNAL SITE OUTLOOK IS DESIGNED BY THE PUBLISHER AND COPYRIGHT PROTECTED. DO NOT COPY!