Osteomalacia
Osteomalacia is defective mineralisation of newly formed adult bone, most often from vitamin D deficiency or phosphate depletion. It causes diffuse bone pain, proximal weakness and fragility or pseudofractures, with a pattern of abnormal mineral metabolism rather than the normal biochemistry of osteoporosis.
Definition
Osteomalacia is defective mineralisation of newly formed bone matrix in adults. It is most often related to vitamin-D deficiency, but calcium depletion, phosphate depletion, impaired vitamin-D activation, malabsorption and medication effects can produce the same mineralisation defect.
First principles
The problem is mineralisation of osteoid
Bone is laid down as an organic osteoid matrix that must be mineralised with calcium and phosphate. When vitamin D, calcium or phosphate supply is inadequate, osteoid accumulates without normal hardening. Adults develop osteomalacia; the analogous defect at open growth plates is rickets. The clinical result is painful, mechanically weak bone and impaired muscle function.
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