RESUMO
To test the hypothesis that high-dose vitamin D2 supplementation would result in a lower incidence of radiographically detectable bone disease, we randomly assigned 40 very low birth weight infants to a control group who received vitamin D2 in a dosage of 400 IU/day and 41 to an experimental group who received a dosage of 2000 IU/day. After 6 weeks, radiographs from all infants were scored blindly for degree of radiographic bone disease, and serum osteocalcin and 25-hydroxyvitamin D levels were measured. Mean vitamin D intake was 360 +/- 141 (SD) IU/day in the control group and 2170 +/- 144 (SD) IU/day in the experimental group. Median 6-week serum 25-hydroxyvitamin D levels were 24 ng/ml (range 3 to 60 ng/ml) in the control group and 68 ng/ml (range 9 to 150 ng/ml) in the experimental group (p less than 0.001). Overall, 20% of the infants had evidence of moderate radiographic bone disease and only 2% were severely affected. The radiographic bone score (median = 2.5) and serum osteocalcin concentration (mean = 21.7 +/- 8.7 ng/ml) in the control subjects did not differ significantly from those in the experimental group (median bone score = 2.0; mean osteocalcin level = 24.1 +/- 7.9 ng/ml). Although there may be a subset of very low birth weight infants who would benefit from high doses of vitamin D, we conclude that no generalized clinical improvement can be attributed to this regimen alone.
Assuntos
Doenças Ósseas/tratamento farmacológico , Recém-Nascido de Baixo Peso , Vitamina D/uso terapêutico , Doenças Ósseas/diagnóstico por imagem , Doenças Ósseas/metabolismo , Calcifediol/sangue , Cálcio/metabolismo , Creatinina/metabolismo , Humanos , Recém-Nascido , Osteocalcina/sangue , Fosfatos/sangue , Radiografia , Distribuição AleatóriaRESUMO
We report two infants with bone deformities and multiple fractures reminiscent of osteogenesis imperfecta, but also having ocular proptosis with orbital craniosynostosis, hydrocephalus, and distinctive facial features. Both infants were normal at birth, but multiple compression fractures of the long bones were noted shortly thereafter, followed by extensive demineralization and culminating in recurrent diaphyseal fractures of the weight-bearing bones before the first birthday. The striking similarity of both the distinctive dysmorphic features and the unique pattern of fractures in two unrelated individuals suggests that this is a previously unrecognized form of osteogenesis imperfecta. Despite the craniosynostosis and hydrocephalus, intellectual performance is unimpaired in both individuals. Bone biopsy in one patient revealed decreased bone volume and increased bone resorption without compensatory new bone formation. Extensive laboratory investigations have not identified a cause, nor have they clarified pathogenesis; further elucidation will require the identification and study of new cases.
Assuntos
Osteogênese Imperfeita/patologia , Craniossinostoses/patologia , Exoftalmia/patologia , Face/patologia , Fraturas Espontâneas/diagnóstico por imagem , Humanos , Hidrocefalia/diagnóstico por imagem , Lactente , Masculino , Osteogênese Imperfeita/diagnóstico por imagem , Radiografia , RecidivaRESUMO
We surveyed both normal children and patient populations to identify the effects of metabolic bone disease and impaired renal function on serum levels of osteocalcin, a vitamin K-dependent protein synthesized in bone. Cord blood osteocalcin was nearly double that of maternal osteocalcin, but there was no correlation between the two. Infants with Apgar scores less than or equal to 7 had a lower mean serum osteocalcin value (8.7 ng/ml, n = 8) than did those with scores of 8 to 10 (16.6 ng/ml, n = 38). Serum osteocalcin elevation coincided with the pubertal growth spurt. In boys, levels decreased to adult values by 18 years of age, as do other indices of bone metabolism; in girls, the levels decreased earlier and had a less pronounced maximum. In children with renal failure, osteocalcin was substantially increased, presumably because of diminished renal clearance of the protein. Children receiving peritoneal dialysis, however, had mean serum concentrations less than half of those seen in children receiving hemodialysis (117 vs 328 ng/ml). The peritoneal dialysate contained significant amounts of osteocalcin, but none was detectable in hemodialysate. Correlation between bone disease and serum osteocalcin was evident in a longitudinal study of one patient with renal failure. Children with various forms of rickets had elevated osteocalcin levels; hypoparathyroidism and osteoporosis were accompanied by variable changes. Serum osteocalcin holds promise as a useful marker of subacute changes in bone metabolism.