Korean Journal of Nephrology 1989;8(2):334-344.

혈액 투석 요법 환자에 있어서의 이온화 칼슘에 대한 임상적 평가

정병천 , 박찬현 , 강종명 , 박한철

Abstract

Abnormal calcium metabolism is invariably present in patients with advanced chronic renal failure. It is the major cause of uremic osteody strophy and it is also often related with anemia, myopathy, myocardiopathy and other manifestations. In human plasma, about a half of the calcium is present as free, ioned form and the rest as bound to plasma protein or complexed with other anions. Of th.e, only ionized calcium plays a key role in regula- tion of parathyroid hormone secretion. It's measurement has been, however, difficult and impractical for a rou- tine laboratory. Extrapolation from total calcium con- tent is often misleading, because the level of total cal- cium is altered by blood pH, protein, albumin, sodium and etc. In order to establish the relationship between total calcium and ionized calcium, a study was conducted in uremic patients. To mininized various factors, only 80 uremic patients, stable on regular hemodialysis, were chosen as the study material. A clinical study on uremic hyperparathyrodism was also conducted comparing with 37 health control. The results were as follows; 1) Compared with healthy control, the dialyzed group showed significantly higher levels of serum creatinine, phosphate and alkaline phosphatase. Levels of were 9.07 and 4.26 mg/dl in control group, and 8.39 and 3.88 mg/dl in dialyzed group (P<0.001, P<0.001 respectively). Mean values of parathyoid hormone were 0.24 ng/ml in control group and 3.55 ng/ml in dialyzed group (P <0. 005). 2) In dialyzed group, alkaline phosphatase and par- athyroid hormone levels were high at the beginning of hemodialysis and formed a plateau at one year after hemodialysis. There was a wide variation of parathyroid hormone levels, generally high within a narrow range of ionized calcium levels and these two markers were statistically unrelated. Parathyroid hormone levels were statistically related with alkaline phosphatase levels but not with total calcium, ionized calcium, or with the products of these and phosphate, repectively. 3) In dialyzed group, inoized calcium levels were not significantly related with pH, CO, content, total protein and albumin. On the other hand total calcium was significantly related with total protein, albumin, pH, and CO, content. In about one third of the patients, there was significant discordance between ionized calcium and total calcium. These data suggest that in assessing uremic metabo- lism, measurement of ionized calcium is undispensable. Extrapolation from total calcium is inaccurate. Most of the regular hemodialysis patients showed high parathyr- oid hormone levels with low serum total and ionized calcium. The parathyroid hormone levels were related best with alkaline phosphatase.