The Facts About Osteoporosis
Pathophysiology, Diagnosis, and Treatment of a Common Bone Disorder
Dec 27, 2008
Osteoporosis is a skeletal condition characterized by a decrease in overall bone density. It affects elderly individuals around the world, particularly postmenopausal women. The disorder often goes unnoticed until a fracture occurs as a result of brittle bones.
Pathophysiology
Human bones have two components that give themselves strength: collagenous proteins and mineralization with calcium and phosphorous. These materials are deposited by bone cells called osteoblasts, which are balanced by bone cells called osteoclasts that break down portions of bone. Decreases in bone density occur when there is imbalance towards osteoclastic activity. A variety of factors can increase the risk of osteoporosis, including but not limited to estrogen deficiency following menopause, immobility, vitamin D deficiency, hyperparathyroidism, alcohol use, and smoking.
Diagnosis
Osteoporosis is considered a clinically silent condition that only manifests itself when an individual has at least one fracture, especially a fracture associated with minimal to no trauma. Common places for such fractures include the hip and the vertebrae. In such cases, a clinician evaluates for possible risk factors of osteoporosis by interviewing the patient and ordering appropriate blood tests.
The diagnose of osteoporosis requires imaging studies. Plain x-rays of bones can show signs of bone loss if it is significant, but the test of choice is a dual-energy x-ray absorptiometry (DEXA) scan. DEXA scans measure the density of bone in certain areas of the body or in the entire body. The results are reported in terms of a standard deviation from a mean bone density. Osteoporosis is defined as a bone density that is at least 2.5 standard deviations below the mean. If the bone density is 1 to 2.5 standard deviations below the mean, the term used is osteopenia.
Treatment
The initial treatment of osteoporosis requires addressing any unresolved fractures, nonsurgically or surgically, and minimizing any active risk factors. Physical activity and supplements of calcium and vitamin D can help strengthen bone and prevent subsequent fractures. If necessary, patients can take medications. Bisphosphonates, such as alendronate sodium (Fosamax) and ibandronate sodium (Boniva), inhibit bone resorption by osteoclasts and are the main choice of osteoporosis treatment. Other options include estrogen replacement and the calcium-lowering hormone calcitonin.
Screening
Given the prevalence of osteoporosis, DEXA scans should be performed every few years to screen for this condition. It should be provided for all women older than 65 years of age, but individuals with risk factors may be screened as early as age 50.
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