Common Questions
How do osteoporosis and osteomalacia differ?
Osteomalacia is a defect in mineralization of osteoid (lack of incorporation of calcium and/or phosphate into the osteoid protein bone matrix). Osteoporosis is a reduction in the quantity of normally mineralized bone.
Radiographically, osteomalacia and osteoporosis may be indistinguishable, as both may show diffuse osteopenia. In osteomalacia, however, looser zones or pseudofractures may be seen, although these findings are rare. Looser zones are small fractures that develop perpendicular to the long axis of the bone and are often bilaterally symmetric. These radiographic lucencies are caused by the lack of mineralization.
Osteomalacia may be mild and asymptomatic or severe, predisposing people to bone deformities, pain, and pseudofractures. Symptoms include vague bone pain, generalized myopathy (particularly in the proximal muscles), and bone tenderness of the appendicular skeleton. Osteoporosis, on the other hand, predominantly affects the axial skeleton and is asymptomatic until fractures occur, leading to acute and chronic pain.
It is imperative to consider osteomalacia in any individual with low bone density, because the treatment differs from that for osteoporosis.
- Feldman D, Glorieux FH, Pike JW. Vitamin D. Academic Press, San Diego 1997.
- Goldman L, Bennet JC. Cecil Textbook of Medicine 2000; 21st ed.