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Osteomalacia

Discussion

  • is a type of metabolic bone disease in which the essential problem is a lack of available calcium or phosphorus (or both) for mineralization of newly formed osteoid;
  • children w/ rickets & adults w/ osteomalacia present w/ similar findings;

etiology of rickets and osteomalacia

anatomic changes in rickets and osteomalacia

  • anatomical and pathological changes differ according to age of patient and the severity of the disorder;
  • rickets affects the growing skeleton & thus affects both the epiphyseal plates as well as the bones of children;
  • osseous changes in osteomalacia are similar to those in children but are much less evident because adult skeleton is metabolically less active;

Clinical Manifestations

  • pts generally complain of easy fatigability, malaise, and bone pain;
  • pain is diffuse and poorly localized and is accompanied by a general tenderness of bones;
  • frx in an elderly individual that is thought to be the result of osteoporosis may be first sign of osteomalacia, & these patients must be evaluated carefully;
    • all symptomatic elderly patients should be screened for occult disease;
  • bizarre complaints may give impression that patient has mental aberration;
  • muscular weakness is often seen in severe cases;
  • proximal muscle weakness may be evident & pt may have T-burg gait;

Radiographs

  • Looser's zones:
    • osteoid seams are insufficiency types of stress frx which are commonly seen in patients with osteomalacia;
    • they are more common in adults than in children;
  • patients may have findings of osteomalacia / renal osteodystrophy such as decreased mineralization, coarsened texture of the bones, "rugger-jersey" appearance of spine, and, occasionally, bowed long bones;
  • most of these patients have chronic renal disease;

Histologic examination

biopsy

  • biopsy is frequently necessary to provide diagnosis, which allows assessment of the number and thickness of osteoid seams per unit area;
  • look for wide osteoid seams;
  • there is less mineralized trabecular & cortical bone per unit volume of bone;
  • tetracycline labeling helps confirm decreased mineralization of osteoid seams;

stress frx

  • unmineralized areas (also called Looser's zones or pseudofractures) are occasionally seen roentgenographically;
  • these zones are caused by rapid resorption & slow mineralization, are generally perpendicular to bone cortex;
  • if stress frx occurs, it may be surrounded by a collar of callus;

osteoid seam

Laboratory Aspects: Osteomalacia

Reference