Hypercalciuria may cause hematuria in children. Abnormalities in renal tubular function have been reported in patients with idiopathic renal hypercalciuria.
Twenty four-hour excretion rates of calcium are an important part of evaluation of any stone, hematuria, etc. The definition of hypercalciuria, however. is not simple. Some disagreement concerning normal values has arisen from previous studies,
perhaps
because of the differences between study populations in race, age, , ethnic background, or diet. We therefore decided to measure the urinary excretion of calcium in Korean children.
The subjects. Grouped in 5 different ages, were 158 patients in the pediatric ward of Severance hospital. Age and case number in each group were as follows:
Ⅰ(neonatal period), 57 cases;
Ⅱ(infancy, 1~11 months), 21 cases;
Ⅲ(early childhood, 1~5 yrs), 20 cases;
Ⅳ(late childhood, 6~11 yrs), 39 cases;
Ⅴ(puberty, 12~15 yrs), 21 cases.
The determinations of the values for 24 hour urine calcium were made by the O-CPC method, creatinine by the Jaffe Rate method, sodium by ion selective electrode (ISE), and magnesium by Magnored dye calormetry.
Factor analysis for the statistical correlation between 24-hour excretion rates of calcium and age, urine volume, and urine sodium was made.
@ES the following results were obtained;
1) the mean level of 24-hour urinary calcium excretion (mg/24hr) was 0.26±0.29(SD) in I, 8.97±13.8 inⅡ, 33.1±42.8 inⅢ, 94.18±85.73 inⅣand 146.4±171.5 inⅤ. There was a statistically significant (p<0.01) difference
inⅠvsⅡ,vsⅢ,andⅢvsⅣ,but
not inⅣvsⅤ.
2) The mean level of 24-hour urine Ca/Cr ratio was 0.03±0.10 inⅠ, 1.28±2.68 inⅡ, 0.19±0.23 inⅢ, 0.22±0.21 inⅣ, and 0.17±0.13 inⅤ.
There was a statistically significant difference inⅠvsⅡ, but not inⅡvsⅢ,ⅢvsⅣvsⅤ.
3) The mean level of 24-hour excretion rate oif calcium by body weight (mg/kg/24hr) was 0.08±0.09 inⅠ, 1.29±1.46 inⅡ, 2.35±3.18 inⅢ, 3.73±3.29 inⅣ, and 3.61±4.30 inⅤ.
There was a statistically significant difference inⅠvsⅡ, but not inⅡvsⅢ,ⅢvsⅣ, andⅣvsⅤ.
4) the twenty-four-hour excretion rate of calcium by boidy weight (mg/kg/24hr) highly correlated with age and 24-hour urine Ca/Cr ratio, but poorly correlated with urine volume and sodium excretion rate.
In coinclution, the above results suggest that a large study must be done to get a normal range of urinary calcium excretion rate and to define the hypercalciuria in Korean children.
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