Bone densitometry in a patient with hypophosphatemic osteomalacia.
A 60-year-old Caucasian woman with a 1-year history of pain at the ribs, spine, and pelvis consulted at our Institute in March 1999. She brought a bone densitometry performed using a Lunar DPX densitometer that showed bone mineral density (BMD) measurements in the osteoporotic range at both the lumbar spine and the femoral neck. As a child she had had bowed legs and had been treated with ultraviolet radiation. Results of the laboratory test performed at our institute showed normal total serum calcium, repeated low serum P levels, and a low renal phosphate threshold with elevated total and bone fraction of alkaline phosphatase with normal intact parathyroid hormone (PTH). A diagnosis of hypophosphatemic osteomalacia due to renal phosphate leak was made. She began treatment with neutral sodium phosphate at 1.5 g/day and calcitriol 0.5 microg/day. Her serum P levels normalized, and there was a progressive decrease in alkaline phosphatase levels. The densitometry showed a very rapid increase in BMD values with normalization at the lumbar spine after 10 months of treatment. This case shows the importance of bone densitometry in the follow-up of patients with suspected osteomalacia.
Negri
Armando L
AL
Instituto de Investigaciones Metabólicas, Libertad 836, 1 piso, 1012, Buenos Aires, Argentina. negri@casasco.com.ar
Bogado
Cesar E
CE
Zanchetta
Jose R
JR
D000469:Alkaline Phosphatase / Q000097:blood / Q000187:drug effects; D015519:Bone Density / Q000187:drug effects*; D002118:Calcium / Q000494:pharmacology; D002762:Cholecalciferol / Q000627:therapeutic use; D005260:Female; D006801:Humans; D017674:Hypophosphatemia / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology*; D008875:Middle Aged; D010018:Osteomalacia / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology; D053402:PHEX Phosphate Regulating Neutral Endopeptidase; D010710:Phosphates / Q000627:therapeutic use; D010758:Phosphorus / Q000097:blood; D011506:Proteins / Q000235:genetics
D010710:Phosphates; D011506:Proteins; D002762:Cholecalciferol; D010758:Phosphorus; D000469:Alkaline Phosphatase; D053402:PHEX Phosphate Regulating Neutral Endopeptidase; C506231:PHEX protein, human; C018279:sodium phosphate; D002118:Calcium