| Theme |
Hypoparathyroidism and Related Problems in Dialysis Patients |
| Title |
Reference value and clinical significance of PTH measurement in chronic renal failure |
| Author |
Kiyoshi Tanaka |
Department of Medicine and Clinical Science, Graduate School of Medicine, Kyoto University |
| Author |
Issei Tanaka |
Department of Medicine and Clinical Science, Graduate School of Medicine, Kyoto University |
| Author |
Akira Sugawara |
Department of Medicine and Clinical Science, Graduate School of Medicine, Kyoto University |
| Author |
Kazuwa Nakao |
Department of Medicine and Clinical Science, Graduate School of Medicine, Kyoto University |
| [ Summary ] |
Circulating PTH levels can be measured by several assay methods in patients with renal osteodystrophy (ROD). Selection of the method and interpretation of the results are dependent on our understanding of the pathophysiology of ROD. Most attention, until recently, was paid to secondary hyperparathyroidism in ROD. However, recent studies have revealed the presence of adynamic bone unrelated to aluminum toxicity in ROD, of which hypoparathyroidism is the underlying mechanism. Thus PTH-C and HS-PTH, which are of adequate sensitivity only to detect PTH elevations, may be insufficient diagnostic methods in ROD. Intact PTH measurement, which is adequately sensitive for detecting lower PTH levels, must be taken into account. Regarding the reference value of PTH in chronic renal failure (CRF), altered tissue responsiveness to PTH must also be considered. Thus, it has been reported that bone in CRF has decreased responsiveness to PTH, and that the PTH receptor number is down-regulated in CRF. Therefore, an attempt to lower circulating PTH into the "normal" range, as defined for non-dialysis subjects, may induce hypoparathyroidism and hence adynamic bone. Although determination of the reference value for PTH in CRF awaits further study on ROD, including adynamic bone, it is prudent to measure the intact PTH value and to maintain it at a "higher than normal" value to avoid hypoparathyroidism and adynamic bone. |