PTH-Related Protein Assays in Advanced Kidney Disease: Implications for Evaluation of Hypercalcemia
Hypercalcemia is a common and potentially serious electrolyte abnormality that is often observed in patients with chronic kidney disease (CKD). When malignancy is considered, parathyroid hormone-related protein (PTHrP) levels are often measured. PTHrP is produced by cancer cells and mimics the effec...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Hindawi Limited
2023-01-01
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| Series: | Case Reports in Nephrology |
| Online Access: | http://dx.doi.org/10.1155/2023/6678658 |
| _version_ | 1797672831963627520 |
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| author | Jobira A. Woldemichael Andres D. Pirela Barry I. Freedman |
| author_facet | Jobira A. Woldemichael Andres D. Pirela Barry I. Freedman |
| author_sort | Jobira A. Woldemichael |
| collection | DOAJ |
| description | Hypercalcemia is a common and potentially serious electrolyte abnormality that is often observed in patients with chronic kidney disease (CKD). When malignancy is considered, parathyroid hormone-related protein (PTHrP) levels are often measured. PTHrP is produced by cancer cells and mimics the effects of parathyroid hormone (PTH) to elevate serum calcium concentrations. The amino and carboxy termini of PTHrP are of functional relevance. C-terminal PTHrP levels accumulate with CKD and can be elevated in normocalcemic CKD patients who lack malignancy. The existence of amino (N)-terminal and carboxy (C)-terminal PTHrP assays and how their concentrations are impacted by CKD are reviewed herein. The case of a patient on maintenance hemodialysis who developed prolonged hypercalcemia with elevated PTHrP concentrations is presented. The workup revealed suppressed intact PTH, low 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D levels. The initial PTHrP assay returned elevated. However, it was unappreciated that it was the C-terminal assay and the patient underwent an unnecessary search for malignancy. A subsequent N-terminal PTHrP assay returned within the normal range. Many commercial labs run the C-terminal PTHrP assay as their first-line test. This can lead to inaccurate differential diagnoses in hypercalcemic patients with CKD. We emphasize the need to specifically request N-terminal PTHrP assays in patients with advanced kidney disease when humoral hypercalcemia of malignancy is suspected. |
| first_indexed | 2024-03-11T21:35:54Z |
| format | Article |
| id | doaj.art-843999ddd4724f4db23da6f4f9685b90 |
| institution | Directory Open Access Journal |
| issn | 2090-665X |
| language | English |
| last_indexed | 2024-03-11T21:35:54Z |
| publishDate | 2023-01-01 |
| publisher | Hindawi Limited |
| record_format | Article |
| series | Case Reports in Nephrology |
| spelling | doaj.art-843999ddd4724f4db23da6f4f9685b902023-09-27T00:00:02ZengHindawi LimitedCase Reports in Nephrology2090-665X2023-01-01202310.1155/2023/6678658PTH-Related Protein Assays in Advanced Kidney Disease: Implications for Evaluation of HypercalcemiaJobira A. Woldemichael0Andres D. Pirela1Barry I. Freedman2Department of Internal MedicineDepartment of Internal MedicineDepartment of Internal MedicineHypercalcemia is a common and potentially serious electrolyte abnormality that is often observed in patients with chronic kidney disease (CKD). When malignancy is considered, parathyroid hormone-related protein (PTHrP) levels are often measured. PTHrP is produced by cancer cells and mimics the effects of parathyroid hormone (PTH) to elevate serum calcium concentrations. The amino and carboxy termini of PTHrP are of functional relevance. C-terminal PTHrP levels accumulate with CKD and can be elevated in normocalcemic CKD patients who lack malignancy. The existence of amino (N)-terminal and carboxy (C)-terminal PTHrP assays and how their concentrations are impacted by CKD are reviewed herein. The case of a patient on maintenance hemodialysis who developed prolonged hypercalcemia with elevated PTHrP concentrations is presented. The workup revealed suppressed intact PTH, low 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D levels. The initial PTHrP assay returned elevated. However, it was unappreciated that it was the C-terminal assay and the patient underwent an unnecessary search for malignancy. A subsequent N-terminal PTHrP assay returned within the normal range. Many commercial labs run the C-terminal PTHrP assay as their first-line test. This can lead to inaccurate differential diagnoses in hypercalcemic patients with CKD. We emphasize the need to specifically request N-terminal PTHrP assays in patients with advanced kidney disease when humoral hypercalcemia of malignancy is suspected.http://dx.doi.org/10.1155/2023/6678658 |
| spellingShingle | Jobira A. Woldemichael Andres D. Pirela Barry I. Freedman PTH-Related Protein Assays in Advanced Kidney Disease: Implications for Evaluation of Hypercalcemia Case Reports in Nephrology |
| title | PTH-Related Protein Assays in Advanced Kidney Disease: Implications for Evaluation of Hypercalcemia |
| title_full | PTH-Related Protein Assays in Advanced Kidney Disease: Implications for Evaluation of Hypercalcemia |
| title_fullStr | PTH-Related Protein Assays in Advanced Kidney Disease: Implications for Evaluation of Hypercalcemia |
| title_full_unstemmed | PTH-Related Protein Assays in Advanced Kidney Disease: Implications for Evaluation of Hypercalcemia |
| title_short | PTH-Related Protein Assays in Advanced Kidney Disease: Implications for Evaluation of Hypercalcemia |
| title_sort | pth related protein assays in advanced kidney disease implications for evaluation of hypercalcemia |
| url | http://dx.doi.org/10.1155/2023/6678658 |
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