musculoskeletal and connective tissue disorders
Osteoporosis
Classification of Osteoporosis
Osteoporosis can develop as a primary disorder of bone turnover or secondarily due to some other factor. The sites of fracture are similar in primary and secondary osteoporosis. Nearly all occurrences of osteoporosis in men and women are primary, without an identifiable underlying cause. Most cases occur in postmenopausal women and older men. However, certain conditions may accelerate bone loss in patients with primary osteoporosis. Gonadal insufficiency is an important factor in both men and women; other factors include decreased calcium intake, Vitamin D Deficiency and Dependency , certain medications, and The major mechanism of bone loss is increased bone resorption, resulting in decreased bone mass and microarchitectural deterioration, but sometimes bone formation is impaired. The mechanisms of bone loss may involve the following: Local changes in cytokine production, particularly involving cytokines such as receptor activator of nuclear factor kappa-B ligand [RANKL] that increase bone resorption by promoting differentiation and maturation of osteoclasts Impaired formation response during bone remodeling, probably caused by age-related decline in the number and activity of osteoblasts, partly related to cytokine-mediated increases in the protein sclerostin Other factors that affect bone resorption such asparathyroid hormone(PTH) andvitamin D refers to the rare cases of fragility fractures in children, adolescents, premenopausal women, or men < 50 years with normal gonadal function and no detectable secondary cause, including those with low bone mass for age (low Z-scores on Dual-energy x-ray absorptiometry (DXA) [DXA] scans). 