ABSTRACT
Metabolic bone disease following urinary diversion seems to have been first described by Turner,1 who in 1929 reported an 18-year-old boy with generalized rickets developing 10 years after implantation of the ureters into the sigmoid colon because of congenital bladder defect. Turner, however, was unaware of a link between the rickets and the urinary diversion. The possibility of bone complications in patients with urinary diversion was first recognized by Boyd2 when in 1931 he reported a 10-year-old boy who 3 years previously had undergone similar
BOX 8.1 PATHOGENESIS OF OSTEOMALACIA AND RICKETS
Abnormal vitamin D metabolism Vitamin D deficiency
Inadequate dermal production of vitamin D3
Inadequate hepatic synthesis of 25-hydroxyvitamin D3
Defective renal synthesis of 1,25-dihydroxyvitamin D3
Defective end-organ response to l,25-dihydroxyvitamin D3
Renal loss of vitamin D-binding protein
Phosphate deficiency Diminished phosphate intake
Impaired renal tubular absorption of phosphate
Defects in mineralization Enzyme deficiency
Circulating inhibitors of calcification
Abnormal bone collagen or matrix
States of rapid bone formation Miscellaneous
Parenteral alimentation
Gastrectomy
Hyperchloremic metabolic acidosis
ureteric transplantation due to exstrophy of the bladder and 2 years later had developed active rickets as well as chronic acidosis, hypocalcemia, hypophosphatemia and nitrogen retention. The rickets resisted treatment with vitamin D until it was combined with large doses of sodium bicarbonate. Rickets and osteomalacia belong to a group of metabolic bone diseases with varying pathogenesis and characterized by deficient mineralization of osteoid (Box 8.1). Rickets involves widening of the growth plate in the distal ends of long bones, whereas in osteomalacia, mineralization is impaired in the cortical and cancellous bone when growth has ceased (Figure 8.1).