A CLINICAL STUDY OF THE HYPERCALCIURIA

HYPERFUNCTION OF PARATHYROID IN THE PATIENTS WITH CALCIUM NEPHROLITHIASIS

Abstract

Oral calcium tolerance test (OCTT) by modified Pak's method was done in 74 patients (55 males, 19 females) with calcium-nephrolithiasis. Depending on the results of urinary calcium-creatinine ratio (Ca/Cr), these patients were able to be classified into 3 distinct subgroups as follows: In the group 1 (33cases), fasting urinary Ca/Cr was higher than control group (normal men) and these patients were presumed to be hypercalciuric on the basis of such as primary hyperparathyroidism (PHPT) or renal hypercalciuria (RH). In the group 2 (18 cases), fasting urinary Ca/Cr was normal but after oral Ca loading (Ca 1.0g) it was elevated to higher range, and this group was defined as a group with absorptive hypercalciuria (AH). In the group 3 (23 cases), both urinary Ca/Cr were normal and this group was defined as normocaliciuric.
In these patients, level of serum Ca (S-Ca), serum C-terminal parathyroid hormone (S-PTH), and except few cases serum ionized Ca (S-Ca⁺⁺) were examined. As expected, the cases, one or more such blood studies were high level (S-Ca>10.0mg/dl, S-PTH>1.0ng/ml, S-Ca⁺⁺>4.50mg/dl), were the patients of group 1 with OCTT. In the group 2 and 3, these blood studies were almost normal.
However, the results of these blood studies in 33 patients of group 1 were variable but were able to be classified into 3 types with mainly level of S-Ca and S-Ca⁺⁺ as follows: (A) S-Ca high (B) S-Ca normal and S-Ca⁺⁺ high (C) S-Ca, S-Ca⁺⁺ normal. And the cases, high level of S-PTH, were found in the patients with type A or B.
The patient of type A (8 cases) were diagnosed as PHPT, type B (12 cases) suspected as RH and type C (8 cases) as crossover to group 1 of AH (in the other 5 cases of group 1, level of S-Ca were normal but level of S-Ca⁺⁺ not examined).
Type A and B were suspected to be hyperparathyroidism and parathyroid function were normal in the patients of type C. So scintigram for parathyroid was done in 18 cases with group 1 patients (type A-8, type B-8, type C-2) and in 16 cases without 2 cases of type C abnormal concentration at parathyroid gland were found. And operative parathyroid exploration was done in these patients with positive findings.
Except one case of type A, abnormal parathyroid glands were found in 15 cases and diagnosed as adenoma (8 cases) and primary hyperplasia (7 cases) histologically. 5 of 7 patients (PHPT suspected) of type A were having adenoma and 5 of 8 of type B (RH suspected) were hyperplasia.
We could not define whether these patients such as type B (fasting urine Ca/Cr high, S-Ca normal, S-Ca⁺⁺ high) were normocalcemic “primary” hyperparathyroidism or “secondary” hyperparathyroidism caused by primary renal Ca leak.
But ratio of renal Ca reabsorpton (% TR-Ca) was tend to be lower than normal men in normocalcemic group 1 patients.