Internal Medicine

0521779407-16 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:18

Osteoporosis 1109

➣Calcium, phosphorus, alkaline phosphatase: usually normal

➣PTH if calcium elevated

➣25-hydroxy vitamin D. Vitamin D inadequacy very common,

must be corrected before any treatment for osteoporosis can be

effective.

➣Free T4, TSH

➣Serum testosterone in men

➣Serum protein electrophoresis if suspicion for myeloma

■Basic urine studies:

➣24-h urine calcium

➣24-h urine free cortisol if suspicion for Cushing syndrome

➣Urine protein electrophoresis if suspicion for myeloma

■Specific Diagnostic Tests

➣Bone mineral density (BMD) evaluation: dual-energy x-ray

absorptiometry (DXA), quantitative CT (QCT)

■World Health Organization BMD Categories:

➣Osteoporosis: >2.5 SD below standard (T ><−2.5)

➣Osteopenia:−1to−2.5 SD below standard (T <−1)

➣Normal: <1 SD below standard (T=+2to−1)

Imaging

■PA and lateral films of thoracic and lumbar spine to identify vertebral

compression fractures. Presence of a single compression fracture

increases subsequent fracture risk 5-fold.

■Metabolic bone series if lab abnormalities; not routinely indicated

differential diagnosis

■Common medical conditions associated with osteoporosis:

➣Alcoholism

➣Rheumatic diseases

➣Intestinal malabsorption syndromes

➣Adrenal cortical excess

➣Osteomalacia

➣Various malignancies

➣Thyrotoxicosis

Primary hyperparathyroidism

management

What to Do first

■Establish whether secondary causes

■Consider specific pharmacologic therapy