In this chapter, the term 'renal osteodystrophy' will be used in a generic sense to include all the clinical syn- dromes of skeletal disease and altered calcium (Ca) and phosphorus (P) homeostasis resulting from chronic renal failure (CRF). The skeletal pathology can include osteitis TAHQgT 0BQAN8 fibrosa and other features of secondary hyperparathy- OUT roidism, osteomalacia, aplastic or adynamic bone disease, PARATHVnOO QLAND osteoporosis, osteosclerosis, and in children, retardation of growth. Emphasis will be placed on the manifestations Figure I. Schema showing the conversion of vitamin D3 (D3) of these syndromes that occur in patients on maintenance to 25-hydroxyvitamin D3 (25(OH)D3 or calciferol) in the liver dialysis with a consideration of pathogenesis, prevention and subsequently to 1,25 dihydroxyvitamin Dj (l,25[OH)2D3 and management. or calcitriol) in the kidney. Vitamin D through a specific action on collagen metabolisnh.There The term, vitamin D, is used to include vitamin D, or are also cellular receptors for calcitriol in the parathyroid cholecalciferol, the naturally occurring sterol present in glands, pancreas, kidneys, and salivary glands, although animals, and vitamin D, or ergocalciferol, a sterol gener- its action in these tissues are uncertain. Recently, calcitriol ated through the ultraviolet irradiation of plant precursors.
