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

Calcium and phosphorus retention in the preterm infant during total parenteral nutrition. A comparative randomised study between organic and inorganic phosphate as a source of phosphorus

The preterm infant fed parenterally is prone to some demineralisation due in part to insufficient Calcium (Ca) and Phosphorus (P) retention. In an attempt to augment Ca and P retention, we prepared a standardised parenteral solution containing calcium gluconate and glucose-1-phosphate (Phocytan) as source of phosphorus, yielding a daily supply of 75 mg/kg Ca and 45 mg/kg P. 28 very low birthweight infants were randomly assigned to receive either this solution (high Ca P ; n = 15) or a conventional formulation containing calcium gluconate and potassium mono- and dibasic phosphate delivering 42 mg/kg Ca and 36 mg/kg P daily (low Ca P ; n = 13). In the high Ca P daily retention was respectively 80% and 99% for Ca and P whereas in the low Ca P group, retention was 70% and 82%. Serum parathormone levels were significantly lower in the high Ca P group. We conclude that parenteral nutrition with a new high Ca P supplement results in an augmented Ca and P retention in very low birthweight infants. This may help to prevent neonatal bone demineralization.

Calcium and phosphorus balance in Very Low Birth Weight babies on Total Parenteral Nutrition

A balance study of Ca and P has been performed in 12 Very Low Birth Wt babies receiving prolonged Total Parenteral Nutrition. The mean intake of both minerals was 54.4 mg/kg/day (range 40-70). In order to avoid the formation and precipitation of CaP crystals in the solution, fructose-1,6-diphosphate was used as a source of P. 30 balance studies were performed between the seven and 63 day of life: they were always positive with a mean retention of 47.4 mg/kg/day of Ca and 48.1 mg/kg/day of P. For both minerals, 88% of the amount infused was retained: the correlation between intake and retention was linear and statistically significative (Ca:r = 0.9, p < 0.0001; P:r = 0.68, p < 0.0001). The post-natal and post-conceptional ages of the babies had no influence on Ca and P balance. The blood levels of Ca and P were poorly correlated to both intake and excretion, and were not as indicative of the mineral balance as the retention rates calculated on the basis of the 24 h urinary excretion of the minerals. A very useful test for clinical monitoring of Ca and P balance proved to be the Ca/creatinine and P/creatinine ratios measured on simple urine samples, which were strongly correlated to 24 h excretion. All infants developed radiological signs of mild osteopenia, but there was no case of acute metabolic derangement or rickets. Our data demonstrated that even in sick VLBW infants on TPN it is possible to achieve good retention rates of Ca and P, which are not different from those observed in well VLBW babies fed a 'standard' premature formula.

Simultaneous infusion of calcium and phosphorus in parenteral nutrition for premature infants: use of physiologic calcium/phosphorus ratio

We hypothesized that parenteral delivery of calcium and phosphorus in a ratio of 1.7:1 would promote retention of these minerals and decrease urinary phosphorus excretion, and that delivery of increased amounts of this ratio would result in higher retentions. Serum levels and retention of calcium and phosphorus were measured as calcium intake was increased from 36 to 76 mg/kg/day in 10 mg increments and as phosphorus intake was adjusted to maintain the 1.7:1 ratio. Five different infants were studied at each of the five levels. The amounts of calcium and phosphorus retained increased steadily and at level 5 were 71.8 +/- 1.2 mg/kg/day and 40.9 +/- 1.7 mg/kg/day, respectively. Over the five levels the average percent calcium retention was 91.4 +/- 4.2 and the average percent phosphorus retention was 89.1 +/- 7.7. The provision of parenteral calcium and phosphorus in a 1.7:1 ratio resulted in a balanced retention of both minerals over the range studied. The use of this calcium/phosphorus ratio appears to be appropriate for the preterm infant receiving total parenteral nutrition.

Phosphorus deficiency syndrome in very low birth weight infants

Inadequate dietary phosphorus intake is a contributing factor to the occurrence of metabolic bone disease in very low birth weight infants. This article reviews the clinical presentation and the pathophysiology of the phosphorus deficiency syndrome in premature infants. Recommendations for therapy and prevention of phosphorus deficiency are presented.

Serum levels of vitamin D metabolites in children receiving total parenteral nutrition

Serum levels of 25-hydroxyvitamin D (25-OHD) and 1,25-dihydroxyvitamin D (1,25-(OH)2D) were measured on 19 occasions in seven children receiving total parenteral nutrition (TPN). The daily intakes of vitamin D3 ranged from 44 to 540 IU/day, and all serum samples were obtained after the same daily intake of vitamin D3 for more than 1 month. There was a significant positive correlation between serum 25-OHD levels and parenteral vitamin D3 intakes (r = 0.90, p less than 0.01). In this study, serum 25-OHD levels in all cases taking 200 to 360 IU/day of vitamin D3 were within the normal range. On the other hand, no significant correlation was found between serum 1,25-(OH)2D levels and vitamin D3 intakes, and serum 1,25-(OH)2D levels were normal or elevated in all cases.

Prophylaxis and treatment of childhood rickets with parenteral cholecalciferol

The safety and efficacy of parenteral cholecalciferol was evaluated in the treatment and prevention of childhood rickets. Children with active disease, and those at high risk for developing rickets were treated either with intravenous or intramuscular cholecalciferol in dosages of 1000 to 1500 IU daily, for periods of 28 to 450 days. All children with rickets responded with radiographic evidence of healing. No child in the prophylaxis group developed bone disease. Side effects were minimal. Parenteral cholecalciferol is a safe and effective therapy for the treatment and prevention of childhood rickets.