Assuntos
Acidose Tubular Renal/complicações , Di-Hidroxicolecalciferóis/uso terapêutico , Raquitismo/etiologia , Bicarbonatos/urina , Cálcio/sangue , Pré-Escolar , Feminino , Humanos , Hiperparatireoidismo Secundário/complicações , Fosfatos/sangue , Raquitismo/tratamento farmacológico , Vitamina D/uso terapêuticoRESUMO
Nine patients with vitamin D-dependency type I were studied. We observed that treatment with large doses of vitamin D altered the phenotypic expression of the disease, thus making a delayed diagnosis difficult. At the time of entry, eight children had hypocalcemia, and seven had hypophosphatemia. Elevated serum immunoreactive parathyroid hormone and low (less than 3 SD from control mean) 1 alpha,25-dihydroxyvitamin D values were constant findings, with no vitamin D deficiency. Despite the elevated serum iPTH, three children had normal urinary phosphate excretion and five had normal urinary cAMP excretion. In the five children tested before treatment, there was no significant change in renal phosphate excretion during an acute parathyroid hormone infusion, although in all a significant rise of urinary cAMP occured. Treatment with calcitriol (0.25 to 2 microgram/day) returned all the biochemical values to normal within four months. In two patients, both supplemented with vitamin D, histomorphometric analysis of iliac crest biopsies revealed severe osteomalacia. After nine and ten months of treatment with calcitriol, there was histologic evidence for improvement of bone mineralization. Since calcitriol requirements may vary during the course of treatment, careful monitoring of biochemical variables is essential.
Assuntos
Calcitriol/análogos & derivados , Di-Hidroxicolecalciferóis/uso terapêutico , Hidroxicolecalciferóis/uso terapêutico , Hipofosfatemia Familiar/tratamento farmacológico , Transtornos Relacionados ao Uso de Substâncias/diagnóstico , Vitamina D/uso terapêutico , Adolescente , Adulto , Análise Química do Sangue , Criança , Pré-Escolar , Colestanotriol 26-Mono-Oxigenase , Ensaios Clínicos como Assunto , AMP Cíclico/urina , Feminino , Humanos , Hipocalcemia/induzido quimicamente , Injeções Intravenosas , Estudos Longitudinais , Masculino , Hormônio Paratireóideo/sangue , Hormônio Paratireóideo/urina , Fosfatos/sangue , Fosfatos/urina , Esteroide Hidroxilases/sangue , Vitamina D/efeitos adversosRESUMO
Osteodystrophy frequently accompanies severe childhood hepatobiliary disease. Proposed causes include malabsorption of vitamin D and calcium, and diminished 25-hydroxylation of vitamin D. Two children, ages 23 and 35 months, with radiographic and biochemical evidence of rickets with extrahepatic biliary atresia, were treated with 1,25-dihydroxyvitamin D3. The minimal effective therapeutic dose and efficacy of 1,25-(OH)2D3 in the treatment of rickets associated with severe childhood hepatic disease were determined. Oral 1,25-(OH)2D3 was ineffective at doses of 0.10 microgram/kg/day. Parenteral doses of 0.20 microgram/kg/day effectively produced radiographic, bone mineral (photon absorptiometric), and biochemical evidence of healing. The need for four times the physiologic dose of 1,25-(OH)2D3 by the parenteral route suggested enhanced catabolism of, or end-organ resistance to, 1,25-(OH)2D3 in our patients with severe cholestatic liver disease treated with phenobarbital.
Assuntos
Di-Hidroxicolecalciferóis/uso terapêutico , Hidroxicolecalciferóis/uso terapêutico , Hepatopatias/complicações , Raquitismo/tratamento farmacológico , Ductos Biliares/anormalidades , Feminino , Humanos , Lactente , Masculino , Raquitismo/etiologiaRESUMO
Rickets with alopecia, an inborn error of vitamin D metabolism, is described in two sisters. The rachitic disorder began during the first year of life and was refractory to 50,000 IU of vitamin D2/day. Surprisingly, both children had marked elevations in serum concentrations of 1,25-(OH)2D. Although the molecular basis for this disorder is not evident to date, intestinal end-organ unresponsiveness to exceedingly high levels of 1,25-(OH)2D was present, in addition to hyporesponsiveness of bone to these high levels of the hormone, since normocalcemia was maintained despite elevated serum levels of PTH. Therapy with oral 1,25-(OH)2D3 failed to reverse the disorder, but oral phosphorus supplements resulted in significant radiographic and clinical improvement.