[Calcium and phosphorus homeostasis in the developmental population. Part II: neonatal disturbances in the serum calcium and phosphorus concentration].
Neonatal hypocalcemia occurs in two forms: early neonatal hypocalcemia typically occurs during the first few days of life and late neonatal hypocalcemia occurs toward the end of the first week of life. Hypercalcemia is the result of imbalance between fluxes of Ca into and out of the extracellular fluid. An increase in net Ca mobilization from the skeleton is generally the primary cause of hypercalcemia. Although the kidney and gastrointestinal tract are involved in the total body Ca homeostasis, they sometimes maintain hypercalcemia. Hypophosphatemia may occur within the first days of birth and may persist for many months. Usually, it has a nutritional basis and occurs most frequently in infants receiving low P intake from parenteral nutrition and in preterm infants fed with human milk. Nonnutritional causes of neonatal hypophosphatemia are much less frequent than nutritional causes. The primary mechanism of hypophosphatemia in nonnutritional-related hypophosphatemia is probably a decreased renal tubular P reabsorption, and may or may not be secondary to elevated PTH. Hyperphosphatemia can have nutritional or nonnutritional causes. Nutritional causes usually occur with the infusion of excessive P content, or an unusual combination of Ca and P delivered from parenteral nutrition solution. Nonnutritional causes include perinatal asphyxia with release of intracellular P to the extracellular compartment, together with a low renal glomerular filtration.
Otto Buczkowska
Ewa
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