Primary hyperparathyroidism: Renal calcium excretion in patients with and without renal stone disease before and after parathyroidectomy

Abstract

The effect of parathyroidectomy on renal calcium excretion per 24 hours in patients with primary hyperparathyroidism with and without a history of renal stone disease was evaluated. Altogether, 91 patients operated on for primary hyperparathyroidism formed the study group for preoperative analysis. Of these patients, 42 were evaluated 1 to 3 years postoperatively. The median preoperative serum calcium level was 2.92 mmol/L, and it was the same for patients with or without renal stones. Preoperatively we found no differences in renal calcium excretion between patients with and without renal stone disease. The median renal calcium excretion was 6.80 mmol/24 hr. At 1 to 3 years after successful parathyroidectomy the group with renal stone disease had higher renal calcium excretion than the group without renal stones (p = 0.03). The reduced effect of parathyroidectomy on renal calcium excretion in the patients with renal stone disease indicates that factors not related to the hyperparathyroid state could contribute to disturbances in renal calcium excretion and hence stone formation. In conclusion, the pathologic basis for renal stone formation in patients with primary hyperparathyroidism might not be the hyperparathyroid state alone; stone formation could be related to other predisposing factors as well. Therefore, although parathyroidectomy can cure hyperparathyroidism, the curative effect on renal stone disease should be reconsidered.

Nephrolithiasis and Renal Calcifications in Primary Hyperparathyroidism

“…Overall, renal calcium excretion is reduced after PTX (18,37,38). However, in some (14,18) but not all (37) studies, an increased 24-h U-Ca has been found after PTX in patients with a history of nephrolithiasis.…”

“…However, in some (14,18) but not all (37) studies, an increased 24-h U-Ca has been found after PTX in patients with a history of nephrolithiasis. In a cohort of 42 patients who had successful PTX, reevaluation of 24-h U-Ca 1-3 yr after surgery showed a higher 24-h U-Ca in the group with renal stone disease compared with the patients without a history of renal stones (18).…”

“…However, in some (14,18) but not all (37) studies, an increased 24-h U-Ca has been found after PTX in patients with a history of nephrolithiasis. In a cohort of 42 patients who had successful PTX, reevaluation of 24-h U-Ca 1-3 yr after surgery showed a higher 24-h U-Ca in the group with renal stone disease compared with the patients without a history of renal stones (18). Similarly, in a standardized clinical workup of patients with renal stones, 24-h U-Ca after surgical cure for PHPT (n ϭ 105) was comparable to non-PHPT renal stone formers (n ϭ 2416) but significantly above 24-h U-Ca in a group of 260 healthy controls (14).…”

“…Because hypercalciuria is an important risk factor for nephrolithiasis, it is likely that the high renal calcium excretion contributes to an increased risk of renal stones. However, the impact of hypercalciuria on the risk of renal stones has so far not been entirely clarified because only some (15)(16)(17) but not all (6,18) studies have shown an increased renal calcium excretion in PHPT patients with renal stones compared with patients without renal stones. Similarly, it is unclear whether hypercalciuria is mainly attributable to an increased calcium release from bone, driven by excess PTH (resorptive hypercalciuria), or rather is linked to increased intestinal calcium absorption (absorptive hypercalciuria).…”

A Pilot Study to Examine the Management of Asymptomatic Hyperparathyroidism in Japanese Patients in Accordance with the Guidelines for Asymptomatic PHPT Proposed at the Third International Workshop in 2008

“…Combining these findings with the increased risk of fracture during daily life in men (8)(9)(10)(11), it may be necessary to review the current differences in the BMD T-score levels between men and women. The renal function is prone to compromise in patients with PHPT due to hypercalcemia and the presence of urinary tract stones, and an eGFR of <60 mL/min/1.73 m 2 (equivalent to CKD stage III) is one of the criterion included in the guidelines for PHPT management (12)(13)(14). In the present study, the mean eGFR was 79.9±26.7 mL/min (men: 74.9±24.9, women: 81.6±27.3), and the number of patients with an eGFR of <60 mL/min was only 17 (six men and 11 women).…”