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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:
- hyperthyroid induced osteopenia:
- chronic use of anticonvulsant medication:
- deficiency states:
- vitamin-D deficiency: (strict vegetarians or an extremely low fat diet);
- gastrointestinal and bilary causes;
- renal osteodystrophy
- fibrous dysplasia or neurofibroma:
- osteomalacia & rickets are rare osteoendocrine or neuroendocrine manifestations of fibrous dysplastic or neurofibromatous dz;
- 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:
- osteoid seams in osteomalacia are wider than seam found in other diseases;
- diff dx: widened osteoid seams may be found in:
- rickets;
- osteomalacia;
- hyperparathyroidism;
- fibrous dysplasia;
- bone-forming tumors;


- Laboratory Aspects: Osteomalacia:
- hypocalcemia
- hypophosphatemia:
- phosphorus level is low or very low depending on type of osteomalacia, except in renal osteodystrophy;
- renal osteodystrophy;
- phosphorus level is invariably high & calcium level will be quite low;
- alk phos:
- usually elevated in all forms of osteomalacia (except hypophosphatasia)


- Reference:

Massive osteolysis.