[Idiopathic hypophosphataemic osteomalacia (author's transl)].
In an adult with sporadic idiopathic osteomalacia an increased phosphate clearance, hypophosphataemia, normocalcaemia, normal serum-25-hydroxycalciferol and an only slightly increased immunoreactive parathormone were found. Intestinal 47Ca absorption was clearly decreased. Radiologically and histologically there was a clear-cut defect of skeletal mineralisation. Under treatment with daily doses of 1-1.25 mg of vitamin D3 the 25-hydroxycalciferol level increased markedly, the immunoreactive parathormone decreased slightly. Serum calcium and hypophosphataemia remained unchanged and intestinal 47Ca absorption was improved. Already 4 weeks after commencing treatment pain and defective gait of the patient disappeared. Radiologically skeletal changes were improved after 7 months. However, histologically no significant bone healing had occurred. The biochemical findings of this disease correspond to those of familial hypophosphataemic (vitamin-D-resistant) rickets. The therapeutic effects of pharmacological doses of vitamin D resemble those in pseudo-vitamin-D-deficient rickets. The pathogenesis of idiopathic osteomalacia of the adult remains unclear. Vitamin D metabolism is unchanged as far as the stage of 25-hydroxycholecalciferol. It is unknown if a disorder of the renal synthesis of 1,25-dihydroxycholecalciferol or a peripheral resistance to the effects of this metabolite exists. In addition a defect of the tubular phosphate reabsorption independent of parathormone and vitamin D is assumed.
D000328:Adult; D002118:Calcium / Q000097:blood / Q000378:metabolism; D002762:Cholecalciferol / Q000627:therapeutic use; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood; D007408:Intestinal Absorption; D008297:Male; D010018:Osteomalacia / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood
D006887:Hydroxycholecalciferols; D010281:Parathyroid Hormone; D010710:Phosphates; D002762:Cholecalciferol; D002118:Calcium
Idiopathische, hypophosphatämische Osteomalazie