- Discussion:
- due to loss of estrogen & affects postmenopausal women;
- 2-3% accelerated (loss for 6-10 yrs which then returns to basal loss of 0.3-0.5 %/year;
- primarily loss of trabecular bone:
- associated w/ greater decline in medullary bone & preservation of cortex;
- trabecular-bone loss is three times the rate of normal
- rate of cortical-bone loss is only slightly above normal;
- there is accelerated bone loss, decr secretion of parathyroid hormone and
increased secretion of
calcitonin and functional impairment in 25 Vit D hydroxylase activity;
- w/ decr production of
1,25(OH)(sub 2)D and therefore decreased calcium absorption;
- defect in calcium absorption may aggravate bone loss;
-
spine in type I:
- loss of structural trabeculae weakens vertebrae & predisposes them to acute collapse;
- vertebral bodies are skeletal elements most at risk of frx in osteoporosis;
- vertebral fractures are usually of the "crush" type associated w/ large deformation and pain;
- fractures:
-
vertebral and
Colles fractures are common;
- vertebral body, distal radius contain large amounts of trabecular bone and are prone to fracture;
- frx occur most frequently in vertebrae, distal aspect of radius, and intertrochanteric region of
the femur in type-I osteoporosis;
- Treatment:
- all pts w/ type I osteoporosis should receive supplemental
calcium: 1 to 1.5 gm / day;
- when high bone turnover is present, cyclic
estrogen / progesterone is appropriate;
-
Vit D: 400 to 800 units / day;
- w/ severe osteoporosis consider use of
calcitonin therapy, especially
if estrogen therapy is contra-indicated or not tolerated;
