SKELETAL MANIFESTATIONS OF MODERATE PHOSPHATE DIABETES

Six patients, with vertebral osteoporosis and reflex sympathetic algod ystrophy syndrome of the lower limbs, due to moderate diabetes, are pr esented. Osteoporosis was documented by low CT scan bone density and m oderate decrease of bone trabecular volume. Histomorphometric studies found a mild increase of resorption areas. All patients had unremarkab le serum phosphorus level (mean :0.91 +/- 0.13) but increase of urinar y phosphorus excretion was documented by phosphate clearance higher th an 20ml/mm, phosphate tubular reabsorption lower than 80% and TmPo4/GF R lower than 0.8mmol/l. Phosphate clearance and phosphate tubular reab sorption are studied in two control groups. Mild phosphate diabetes, o f unknown incidence and prevalence (need for prospective studies) may be the vector of osteoporosis, vertebral and peripheral. The diagnosis of PD requires determination of phosphate clearance, phosphate tubula r reabsorption, TmPo4/GFR and these tests may be useful in the diagnos tic work up of bone demineralization disorders. We thought that osteop orosis could be the result of progressive dissolution of bone apatite crystals necessary to maintain normal or sub-normal blood phosphate le vel in spite of the phosphate diabetes.