Rickets in premature infants receiving parenteral nutrition: a case report and review of the literature.

There is a multifactorial etiology for rickets in premature infants receiving total parenteral nutrition. As an example of this, we describe a premature infant fed almost exclusively parenterally for the first 8 months of life who developed biochemical and radiologic evidence of rickets despite receiving vitamin D, calcium, and phosphorus at presently recommended levels. From our experience and a review of previous literature, there appears to be considerable uncertainty regarding the intravenous requirements of calcium, phosphorus, and vitamin D, particularly in low-birth weight infants. Therefore, measurements of serum 25-hydroxyvitamin D levels, vitamin D, and mineral intakes, and calcium and phosphorus excretion might be clinically useful for monitoring premature infants receiving total parenteral nutrition. Further research delineating more precisely the vitamin D, calcium, and phosphorus requirements of such infants is also suggested.