Review Question - QID 107095

This patient, with normal lab values, has osteoporosis, which is an age-related decrease in bone mass in which bony trabeculae become thinner.

Osteoporosis is a common disorder of bone metabolism that can predispose to fracture. Osteoporosis is an age-related decrease in bone mass secondary to uncoupling of osteoclast-osteoblast activity. In osteoporosis, the existing bone is adequately mineralized. This is in contrast to osteomalacia, in which osteoid is inadequately mineralized. Findings in osteoporosis include thinned cortices and loss of trabecular bone.

Figure A depicts a radiograph of an osteoporotic spine with two compression fractures labeled "1" and "3."

Incorrect Answers:
Answer 1: Subperiosteal bone resorption is associated with hyperparathyroidism. The patient would have an elevated parathyroid hormone in primary hyperparathyroidism which this patient does not.

Answers 2-3: Vitamin D deficiency and excessive unmineralized osteoid are findings in osteomalacia. In osteomalacia, you would have decreased calcium and phosphate levels and increased levels of parathyroid hormone and alkaline phosphatase. This patients labs are all normal.

Answer 5: Hypocalcemia is not seen in osteoporosis, which classically has normal serum calcium and vitamin D levels. Hypocalcemia is seen in osteomalacia.

Bullet Summary:
Osteoporosis is an age-related decrease in bone mass characterized by thinning of the bony trabeculae, and lab values for calcium, phosphate, alkaline phosphatase, and parathyroid hormone levels are normal.