• It is characterized by decreased bone mass, with thinning of the cortices and loss of trabeculae, leading to increased bone fragility and risk of fracture. Bone density (and bone loss) can be quantified with dual energy x-ray absorptiometry.
    • Osteopenia is defined as a bone mass 1.0 to 2.5 standard deviations below the mean peak bone mass of a sex- and height-matched control pop- ulation.
    • Osteoporosis is defined as a bone mass value more than 2.5 standard deviations below the peak bone mass of a sex- and height-matched control population.
    • Etiology
      • The most common types of osteoporosis are postmenopausal osteo- porosis, characterized by high turnover of bone, and senile osteoporosis, which occurs in older men and women.
      • Osteoporosis may be secondary to hypogonadism, hyperparathyroidism, hyperthyroidism, or hypercortisolism.
      • It is associated with malnutrition (eg, calcium deficiency, protein malnutrition, vitamin C deficiency, and alcoholism), malabsorption, neoplastic disorders (eg, multiple myeloma, leukemia, lymphoma, and systemic mastocytosis), and abnormalities of bone collagen (eg, osteogenesis imperfecta).
      • Drugs such as corticosteroids, heparin, methotrexate, and GnRH analogues all increase bone loss. Immobilization also promotes bone loss.
    • Clinical Features
      • Osteoporosis is characterized by the occurrence of fracture with minimal trauma and normal serum levels of calcium, phosphate, and alkaline phosphatase.
      • Fractures can occur with minor trauma and be axial or appendicular. Osteoporotic fractures heal normally.
      • Vertebral fractures lead to loss of height and spinal deformity (kyphoscoliosis and dowager hump).
      • Other osteoporotic fractures include those of the hip and distal radius (Colles fracture).
      • The serum levels of calcium, phosphate, and alkaline phosphatase are normal in osteoporosis.
      • The serum level of alkaline phosphatase may be increased slightly during fracture healing.
      • Lateral spine radiographs show a loss of horizontal trabeculae and an apparent prominence of the vertical trabeculae, biconcave vertebrae, and a decrease in vertebral height.
      • Bone mineral density can be assessed by dual energy x-ray absorptiometry of the lumbar vertebrae (although vessel wall calcification and vertebral deformity with advancing age can make this measurement unreliable) or the hip.
      • A decrease of 1 standard deviation from peak bone density of a control population leads to a doubling of the fracture risk.
    • Diagnosis
      • The diagnosis of osteoporosis is based on the finding of low bone mass with or without fractures and the exclusion of other causes of osteopenia, such as osteomalacia, multiple myeloma, and metastatic disease.
      • Bone densitometry should be used as a screening study for patients at risk of osteoporosis (eg, postmenopausal women not taking preventive measures).
      • Bone densitometry is indicated for patients who have radiologic evidence of previous vertebral fracture.
      • It also is helpful in determining the need for surgery in hyperparathyroidism.
      • During the evaluation of a patient who has a fracture, it is impor- tant to remember that osteomalacia may coexist with osteoporosis.
    • Prevention and Treatment of Osteoporosis
        • To a certain extent, bone loss can be prevented by timely estrogen replacement in women at and beyond menopause and by the provision of adequate calcium and vitamin D intake in all adults
          • In premenopausal women and men younger than 65 years, 1,000 mg daily of elemental calcium; in postmenopausal women and men older than 65 years, 1,500 mg daily
      • Other measures to ensure attainment (and maintenance) of adequate bone mass include regular weight-bearing exercise and avoidance of alcohol and tobacco abuse.
      • Estrogen replacement
        • effective for the prevention and treat- ment of osteoporosis in women who do not have contraindications to it
        • Estrogen can be given orally or transdermally. Women receiving estrogen replacement therapy require a breast examination and mammography annually.
        • To decrease the risk of endometrial hyperplasia, progesterone is also administered in a cyclical or continuous fashion if the patient has an intact uterus.
      • Alendronate and risedronate are oral bisphosphonates with potent antiresorptive effects; they prevent bone loss and increase bone density.
        • They have been shown to reduce fracture risk and to be effective in preventing steroid-induced bone loss.
        • Bisphosphonates are now regarded as first-line therapy in the treatment of osteoporosis.
        • Side effects include dyspeptic symp- toms and esophagitis, particularly if the medication is taken incorrectly.
        • Oral bisphosphonates should be taken in the morning with a glass of water and on an empty stomach (any food or other drink may interfere with intestinal absorption), and the patient should not lie down for 30 to 60 minutes after the dose.
      • Calcitonin is a weak antiresorptive agent and is administered by nasal spray.
        • Very useful for management of painful vertebral fractures.
      • .Recombinant PTH is also now available for treatment of osteo- porosis after clinical trials demonstrated the ability of this agent to increase bone formation and bone mass when given by daily sub- cutaneous injection.
        • This treatment is indicated for patients who have not shown improvement with bisphosphonate therapy or who are unable to tolerate those drugs orally or intravenously.
        • Prior radiotherapy is a contraindication to PTH therapy because of the risk of sarcoma.

      What is Osteoporosis and How to prevent it
      Osteoporosis-3D Medical Animation
      This is an 3D medical animation video to show what is osteoporosis and how it cause weakness to bone and the effect of osteoblast and osteoclast cells in it.also it shows the later stage and diagnosis of osteoporosis

      Please note that this video is not my copyrighted material.I am just sharing my collection from internet.So the credit goes to the real copyright owners.
      Osteoporosis Causes, Symptoms and Prevention
      Osteoporosis – CRASH! USMLE Step 2 and 3
      (Disclaimer: The medical information contained herein is intended for physician medical licensing exam review purposes only, and are not intended for diagnosis of any illness. If you think you may be suffering from any medical condition, you should consult your physician or seek immediate medical attention.)
      Osteoporosis [HD Animation]
      What is Osteoporosis?