24-hour urinary calcium in primary hyperparathyroidism
| Autor: | Carrie E. Black, Andrew C. Urquhart, Richard L. Berg |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Parathyroidectomy
Adult Male medicine.medical_specialty endocrine system diseases medicine.medical_treatment Urology chemistry.chemical_element Parathyroid hormone Calcium Sex Factors Internal medicine Medicine Humans Hypercalciuria Letters Vitamin D Aged Retrospective Studies Community and Home Care Calcium metabolism Aged 80 and over Familial hypocalciuric hypercalcemia business.industry Age Factors General Medicine Middle Aged medicine.disease Hyperparathyroidism Primary Urinary calcium Endocrinology chemistry Parathyroid Hormone Female business Primary hyperparathyroidism |
| Zdroj: | Clinical medicineresearch. 11(4) |
| ISSN: | 1554-6179 |
| Popis: | The normal physiology of calcium metabolism is complex and depends on many factors such as renal function, diet, and age. When this normal metabolism is disrupted, it can acutely lead to hypercalcemia, which causes an increase in urinary calcium excretion through mediation of the calcium sensing receptor (CaSR) in the kidney. Hypercalciuria has been used as a diagnostic marker and indicator for parathyroidectomy in patients with primary hyperparathyroidism (PHPT). Urinary calcium excretion as a function of serum calcium was demonstrated more than 50 years ago.1 However, it is not clear if 24-hour urine calcium levels correlate with preoperative total serum or ionized calcium, parathyroid hormone (PTH), and vitamin D in patients with primary hyperparathyroidism. The 24-hour urinary sample, in addition to serologic studies, has historically been part of the standard diagnostic evaluation for patients suspected of PHPT. The use of 24-hour urine studies in PHPT has served two primary functions: elevated urinary calcium was thought to be a risk factor for nephrolithiasis, and 24-hour urine calcium studies have been used to distinguish asymptomatic PHPT from familial hypocalciuric hypercalcemia (FHH). However, guidelines published in the Journal of Clinical Endocrinology and Metabolism in 2009 no longer recommend hypercalciuria as a criterion for parathyroid surgery.2 The omission of urinary calcium in the updated guidelines for PHPT stems from new perspectives on the pathogenesis of nephrolithiasis. In the absence of nephrolithiasis, hypercalciuria alone is not considered to be an indication for surgery for PHPT; however, other surgeons still regard urinary calcium excretion of >400 mg an indication for surgery.2,3 The other role for urinary calcium studies in the workup of hypercalcemia is to rule out FHH, which is caused by a mutation that inactivates the CaSR, a G protein-coupled receptor expressed in the parathyroid gland and renal tubule. Patients with FHH typically present with hypercalcemia, normal to mildly elevated PTH, and hypocalciuria.4–6 If there is a strong suspicion for FHH, the presence of the mutation in the CaSR gene can be detected using readily available polymerase chain reaction techniques. FHH is an asymptomatic, benign disease; thus, it is important to make the distinction from PHPT, since parathyroidectomy is not indicated in this condition.7,8 For most patients presenting in our practice for evaluation of parathyroidectomy in the setting of primary hyperparathyroidism, a 24-hour urinary calcium level is obtained during the preoperative workup. Given the changing guidelines, with urinary calcium levels no longer a criterion for parathyroidectomy, we questioned the need for 24-hour calcium levels in patients with PHPT and wondered whether the urine calcium levels could be predicted from the elevated serum calcium levels. Therefore, we sought to determine if there was a correlation between 24-hour urinary calcium levels and serum and urinary laboratory markers relevant in this disease process. |
| Databáze: | OpenAIRE |
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