Abstract
In VLBW infants, we studied the theses that in early neonatal hypocalcemia, 1)serum PTH would rise, 2)serum CT would decline, and in response to IV Ca infusion, 3)serum PTH would be lowered, 4)serum CT would rise. Fifteen AGA infants, gestation <32 wks., bt.wt. < 1500 gms. were enrolled in the study. In 8 infants whose serum Ca declined <6.0 mg/dl, changes in serum Ca,Mg,P,PTH,CT and blood iCa were evaluated at 8 ±4 hrs.(baseline), when serum Ca declined to < 6.0 mg/dl (pre-Ca), immediately post-infusion of 18 mg/kg of Ca++ as Ca gluconate (post-Ca). Serum Ca declined from 7.9 ± 0.6 baseline (mean ± s.e.) to 5.2 ±0.2 mg/dl, pre-Ca, p < 0.025, and rose to 9.17 ± 0.74 mg/dl post-Ca, p< 0.025 and 7.1 ± 0.5 mg/dl at 8 hr.post-Ca. Whole blood iCa declined from 4.82 ± 0.24 to 3.72 ± 0.19 mg/dl pre-Ca, p < 0.025, and rose to 6.68 ± 0.32 post-Ca, p< 0.025 and 4.12 ± 0.21 mg/dl at +8 hr. post-Ca. Serum Mg and P did not change significantly. Serum PTH (RIA, mid-molecule, N 29 to 85) rose from 116 ± 17 to 204 ± 34 p mol/l pre-Ca, p< 0.01 and declined to 149 ± 22 post-Ca, p < 0.01, and was 187 ± 28 p mol/l at +8 post-Ca. Serum CT (RIA, adult N 32 to 102) was 751 ± 150, 738 ± 115, 895 ± 206 and 551 ± 94 pg/ml at these times, p < 0.005 vs. term infant values, changes not significant. Thus, in infants < 32 wks. gestation, serum PTH rises in early neonatal hypocalcemia and is suppressed by IV Ca infusion; serum CT is markedly elevated and is not lowered in early neonatal hypocalcemia, and does not rise further in response to IV Ca infusion in VLBW infants. We suggest that hypercalcitonemia occurs in VLBW infants, and serum CT concentrations are unresponsive to changes in serurn Ca.
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Venkatarannan, P., Blick, K., Fry, H. et al. 1550 MARKEDLY ELEVATED SERUM CALCITONIN (CT) REFRACTORY TO SERUM CA CHANGES AND CARESPONSIVE SERUM PARATHYROID HORMONE (PTH) IN HYPOCALCEMIC VERY LOW BIRTH WEIGHT (VLBW) INFANTS. Pediatr Res 19, 369 (1985). https://doi.org/10.1203/00006450-198504000-01574
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DOI: https://doi.org/10.1203/00006450-198504000-01574