Journal Article•
Neonatal hypocalcemia in low birth weight infants
TL;DR: Biochemical determinations showed that, in hypocalcemic infants, there were lower serum total calcium values at 8 hours of life, prior to the actual development of hypocalcemia at 29 hours, and three signs were significantly related to hypocalCEmia, namely, twitching of one or more extremities, high-pitched cry, and hypotonia.
Abstract: During an 8-month period, 37 of 124 infants (29.8%) admitted to a low birth weight (LBW) nursery developed hypocalcemia at a mean age of 29 hours. Ten factors were associated with hypocalcemia, three of which appear particularly relevant: (1) low gestational age (32 weeks or less) with appropriate birth weight, (2) low oral calcium intake, (3) correction of acidosis with NaHCO3. Biochemical determinations showed that, in hypocalcemic infants, there were: (1) lower serum total calcium values at 8 hours of life, prior to the actual development of hypocalcemia at 29 hours; (2) elevated serum phosphorus values; (3) acidotic values in the first hours of life, corrected to normal values at the time of hypocalcemia, and (4) lower serum protein values at 8 hours of life. Three signs were significantly related to hypocalcemia, namely, twitching of one or more extremities, high-pitched cry, and hypotonia.
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TL;DR: Critical areas for future research on the nutritional requirements specific for preterm-LBW infants are identified and recommendations for nutrients not required in formula for term infants such as lactose and arginine are identified.
Abstract: Achieving appropriate growth and nutrient accretion of preterm and low birth weight (LBW) infants is often difficult during hospitalization because of metabolic and gastrointestinal immaturity and other complicating medical conditions. Advances in the care of preterm-LBW infants, including improved nutrition, have reduced mortality rates for these infants from 9.6 to 6.2% from 1983 to 1997. The Food and Drug Administration (FDA) has responsibility for ensuring the safety and nutritional quality of infant formulas based on current scientific knowledge. Consequently, under FDA contract, an ad hoc Expert Panel was convened by the Life Sciences Research Office of the American Society for Nutritional Sciences to make recommendations for the nutrient content of formulas for preterm-LBW infants based on current scientific knowledge and expert opinion. Recommendations were developed from different criteria than that used for recommendations for term infant formula. To ensure nutrient adequacy, the Panel considered intrauterine accretion rate, organ development, factorial estimates of requirements, nutrient interactions and supplemental feeding studies. Consideration was also given to long-term developmental outcome. Some recommendations were based on current use in domestic preterm formula. Included were recommendations for nutrients not required in formula for term infants such as lactose and arginine. Recommendations, examples, and sample calculations were based on a 1000 g preterm infant consuming 120 kcal/kg and 150 mL/d of an 810 kcal/L formula. A summary of recommendations for energy and 45 nutrient components of enteral formulas for preterm-LBW infants are presented. Recommendations for five nutrient:nutrient ratios are also presented. In addition, critical areas for future research on the nutritional requirements specific for preterm-LBW infants are identified.
372 citations
TL;DR: Serum immunoreactive parathyroid hormone (iPTH) and plasma total calcium, ionized calcium, magnesium, and phosphorus levels were determined during the first 9 days of life in 137 normal term infants, 55 "sick" infants, and 43 hypocalcemic infants to indicate thatParathyroid secretion is normally low in the early new born period and impaired parathyro function is present in most infants with neonatal hypocalcemia.
Abstract: Serum immunoreactive parathyroid hormone (iPTH) and plasma total calcium, ionized calcium, magnesium, and phosphorus levels were determined during the first 9 days of life in 137 normal term infants, 55 "sick" infants, and 43 hypocalcemic (Ca <7.5 mg/100 ml; Ca(++)<4.0 mg/100 ml) infants. In the cord blood, elevated levels of plasma Ca(++) and Ca were observed, while levels of serum iPTH were either undetectable or low. In normal newborns during the first 48 h of life there was a decrease in plasma Ca and Ca(++), while the serum iPTH level in most samples remained undetectable or low; after 48 h there were parallel increases in plasma Ca and Ca(++) and serum iPTH levels. Plasma Mg and P levels increased progressively after birth in normal infants. In the sick infants, plasma Ca, Ca(++) and P levels were significantly lower than in the normal newborns, while no significant differences were found in the plasma Mg levels. The general pattern of serum iPTH levels in the sick infants was similar to that observed in the normal group, though there was a tendency for the increase in serum iPTH to occur earlier and for the iPTH levels to be higher in the sick infants. In the hypocalcemic infants, plasma Mg levels were consistently lower than in the normal infants after 24 h of age, while no significant differences were found in the plasma P levels. Hyperphosphatemia was uncommon and did not appear to be a contributing factor in the pathogenesis of hypocalcemia in most infants. Most of the hypocalcemic infants, including those older than 48 h, had inappropriately low serum iPTH levels. Evidence obtained from these studies indicates that parathyroid secretion is normally low in the early new born period and impaired parathyroid function, characterized by undetectable or low serum iPTH, is present in most infants with neonatal hypocalcemia. Additional unknown factors appear to contribute to the lowering of plasma Ca in the neonatal period. The net effect of unknown plasma hypocalcemic factor(s) on the one hand and parathyroid activity on the other may account for differences in plasma Ca levels observed between normal, sick, and hypocalcemic infants. Depressed plasma Mg is frequently present in hypocalcemic infants. To what degree the hypomagnesemia reflects parathyroid insufficiency or the converse, to what degree parathyroid insufficiency and hypocalcemia are secondary to hypomagnesemia, is uncertain.
194 citations
Cites background from "Neonatal hypocalcemia in low birth ..."
...5 mg/100 ml (16), or less than 7 mg/100 ml (17)....
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...In another study Tsang and Oh (17) found that hypocalcemic low birth-weight infants...
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...30 (17) (11) (12) (10) (12) mal group, the differences were not statistically sig-...
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TL;DR: The study suggests that neonatal hypocalcemia results from functionally immature or suppressed parathyroids that are unable to maintain normocalceemia in the presence of hyperphosphatemia.
132 citations
TL;DR: It is speculated that relative maternal hyperparathyroidism leading to fetal hypoparathyroidistan may be a factor in the pathogenesis of neonatal hypocalcemia in infants of diabetic mothers.
123 citations
TL;DR: Parathyroid function was found to be impaired in infants of shortened gestational age and in infants during the first two days of life, and it is speculated that fetal hypercalcemia is a factor in suppression of fetal parathyroidfunction.
119 citations