Osteoporosis

Osteoporosis is a condition that causes thinning of the bones. This can result in vertebral fractures, deformity (kyphosis) and even severe disability.Osteoporosis and related spine fractures are largely treatable and preventable with medications, calcium intake, and kyphoplasty or vertebroplasty surgery.

 

 

 

 

 

 





Vertebral fracture


Kyphosis


Hip fracture


kyphoplasty

Osteoporosis is a disease caused principally by the significant loss of bone mineral density (BMD).


Early in life, more bone is laid down than is removed, and an individual’s peak bone mass is typically achieved by around age 30.


Factors influencing the peak bone mass

 

After peak bone mass is reached, the remodeling process (the process of laying down new bone and removing old bone) takes away more bone than is replaced.

Hence, the bones are more prone to osteoporosis (and consequently to fracture). Thus, the process of bone loss typically begins between one’s early to late thirties. Starting from about that age to the onset of menopause, women lose a certain amount of bone steadily every year, as follows:
Trabecular bone (the spongy bone inside the hard, cortical bone) is lost at a rate of about 1% per year
Cortical bone (the hard bone) is lost at a rate of about 0.5% per year


Cortical bone – Cancellous bone

Estrogen play an important part in maintaining bone strength because it helps keep bone remodeling (which is now taking away more bone than is added) rates low. There are two lines of cells for bone remodeling, the bone-resorbing cells (osteoclasts) and the bone-forming cells (osteoblasts). Without estrogen, the osteoclasts are favored and more bone is resorbed (removed) than laid down, resulting in thinning of the bone.


Osteoblasts


Osteoclasts


The bone remodelling process

Type I osteoporosis(postmenopausal osteoporosis) can be significantly influenced by several preventive measures. Most of these measures are in the hands of the individual and should be started as early in life as possible.
An individual’s peak bone mass is typically achieved by the age of 30. The amount of bone that is obtained at one’s peak, and how much is retained thereafter, is influenced by several factors, including:

1. Genetics and osteoporosis
It is important for individuals to know their genetic predisposition to osteoporosis. Genetics play an important role—it is estimated that about 75% of an individual’s peak bone mass is influenced by genetics. There are genes that code for Vitamin D receptors and for estrogen receptors that both significantly affect peak bone mass. If one is genetically predisposed to osteoporosis, then exercise, diet and regular bone mass testing are even more important.


2. Exercise and osteoporosis
Weight bearing exercise (which refers to activity that one performs while on their feet that works the bones and muscles against gravity) and muscle contraction combined have been shown to effectively increase bone density in the spine. It is recommended that an individual must perform 20 to 30 minutes of aerobic exercise 3 to 4 times weekly to increase bone mass.Individuals already diagnosed with osteopenia or osteoporosis should discuss their exercise program with their physician to avoid fractures.

The gold standard for diagnosis of osteoporosis is dual energy x-ray absorption scan (DEXA scan). The test is performed by passing low energy x-rays through a bone (e.g. spine, hip or wrist). The test takes about ten minutes, is painless, and is associated with very limited radiation exposure. The values generated by the test can then be compared to both:

• Young adult population—called a "T score", this test measures the variance between the patient and the young adult baseline. A score above -1 is considered normal; a score between -1 and -2.5 is considered osteopenia; and a score below -2.5 is considered osteoporosis. For each -1 standard deviation in T score there is a 3 times increased risk of hip fracture and a 2.5 times risk of spine fracture.
• Age- and gender-matched control groups—a "Z score" measures the variance between the patient and control groups’ amount of bone. The control group consists of other people in the patient’s age group of the same size and gender. An unusually high or low score may indicate the need for additional tests.


The DEXA method of bone density measurement.

Using statistical analysis, the DEXA scan diagnostic study can indicate if someone is at increased risk of sustaining a fracture. According to the National Osteoporosis Foundation, bone mineral density testing is recommended in the following situations:

• All women over age 65
• Postmenopausal women under age 65 who have multiple risk factors
• At menopause, if undecided about hormone replacement therapy
• Abnormal spine x-rays
• Long-term oral steroid use
• Hyperparathyroidism (over-active parathyroid gland)

An osteoporosis diagnosis distinguishes whether or not osteoporosis is a primary problem or is secondary to another problem. Therefore, a thorough history and physical examination, as well as the appropriate diagnostic tests, need to be obtained. It is important to distinguish primary from secondary because the treatments are often different.


Typical Bone Mineral Density measurement with DEXA method 


Risk Factors for Osteoporosis
Several key risk factors for developing osteoporosis include:
• Advanced age. Those over 65 years of age are at particular risk.
• Gender. Women are at much greater risk, losing bone more rapidly than men due to menopause. However, men are also at risk and constitute 20% of the patient population with osteoporosis.
• Family and personal history. This includes family history of osteoporosis, history of fracture on the mother’s side of the family, and a personal history of any kind of bone fracture as an adult (after age 45).
• Race. Caucasian and Asian women are at increased risk.
• Body type. At greater risk are small-boned women.
• Menstrual history and menopause. Normal menopause alone increases a woman’s risk of osteoporosis. Early menopause or cessation of menstruation before menopause increases the risk even more.

(Males) Hypogonadism
• Lifestyle. Lifestyle behaviors that increase osteoporosis risk include: calcium and/or vitamin D deficiency; little or no exercise, especially weight-bearing exercise; alcohol abuse; cigarette smoking.
• Chronic diseases and medications. Certain types of medications can damage bone and lead to what is termed “secondary osteoporosis”. This type of osteoporosis occurs in 20% of women and 40% of men with osteoporosis. Included in this category are certain medications to treat endocrine disorders such as hyperthyroidism, marrow disorders, collagen disorders, gastrointestinal problems and seizure disorders. Long-term use of glucocorticoids (oral steroids) to treat diseases such as asthma or arthritis can be particularly damaging to bone.

Osteoporosis Treatment
Once the appropriate medical history, physical exam and diagnostic tests have been obtained and a diagnosis of primary osteoporosis has been made, treatment is warranted. Treatment for osteoporosis typically includes education on diet/nutrition, exercise (if no fractures) and medications. The goal of osteoporosis treatment is to prevent fractures.


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First, education regarding the appropriate calcium and Vitamin D intake, as well as overall nutrition, is necessary. As appropriate, exercise and fitness is also important to help maintain bone density and reduce the risk of falls.

There are a number of medications to treat osteoporosis and help reduce the risk of fractures. In general, these medications work by helping to strengthen the bones and prevent further bone loss. Medications currently approved by the U.S. Food and Drug Administration for the prevention and/or treatment of osteoporosis are:

Osteoporosis medications that slow or stop bone resorption
• Bisphosphonates
• Calcitonin
• Selective Estrogen Receptor Modulators, e.g., Raloxifene
• Estrogen/hormone therapy
• Osteoporosis medications that increase bone formation
• Teriparatide, a parathyroid hormone


Bisphosphonates
This class of medications, which includes Alendronate (e.g., Fosamax), Ibandronate (e.g., Boniva) and Risedronate (e.g, Actonel), are used to prevent and treat osteoporosis. Bisphosphonates work by slowing the rate of bone thinning, which can prevent the development of osteoporosis and reduce the risk of fracture in people who already have osteoporosis. They are taken orally.

• Alendronate
The use of Alendronate (e.g. Fosamax) causes a shift of bone balance toward bone formation by inhibiting bone resorption and has been shown to increase bone mass. Alendronate is significantly more expensive than estrogen, but its ability to prevent fractures is very similar to estrogen.

• Ibandronate
Approved for postmenopausal osteoporosis, Ibandronate (e.g., Boniva) is taken orally once per month. The use of Ibandronate reduces bone loss, increases bone density and reduces the risk of spine fractures.

• Risedronate
Approved for postmenopausal osteoporosis and for glucocorticoid-induced osteoporosis (e.g., from long-term use of prednisone or cortisone), Risedronate (e.g., Actonel) is taken orally on a daily or weekly basis. The use of Risedronate reduces bone loss, increases bone density and reduces the risk of spine and non-spine fractures.

• Calcitonin
Calcitonin (e.g. Miacalcic) is a hormone that is produced naturally in the body, and it is now available as a prescription medication. It can be taken in injection form or intranasal (through a nose spray). This has been found to increase bone density mainly in the spine. Recently, there is a notice for cancer predisposition, after long term intake. The usage remains for short term therapy for Paget disease.

Raloxifene, a Selective Estrogen Receptor Modulator (SERM) Brand name Evista, Raloxifene is part of the Selective Estrogen Receptor Modulators (SERMs) class of drugs developed to provide the benefits of estrogens without their disadvantages. Approved for postmenopausal osteoporosis, Raloxifene is taken orally once a day and is shown to increase bone mass and reduce the risk of spine fractures.


Estrogen therapy / Hormone replacement therapy
Estrogen replacement therapy had been widely used to treat symptoms of menopause in post-menopausal women. To reduce a woman's risk of developing endometrial cancer, doctors often prescribe the hormone progestin in combination with estrogen for those women who have an intact uterus. This combination is called ET/HT (estrogen therapy/hormone replacement therapy). Because of its ability to decrease the risk of fractures in the hip and spine in postmenopausal women, estrogen replacement therapy and ET/HT has also been used in the treatment of osteoporosis.

Teriparatide
Teriparatide is the only approved treatment for osteoporosis that increases bone formation leading to increased bone mineral density. It is a man-made form of the naturally occurring parathyroid hormone which regulates calcium and phosphate metabolism in bones. Teriparatide is approved for use for up to 24 months as a self-administered daily injection in men with high fracture risk and in postmenopausal women. In men, studies show fracture reduction in the spine; in postmenopausal women, fracture reduction was shown in the spine, hip and other bones.

Newer drug innovations

Zoledronic Acid
Aclasta is the Novartis brand name of zoledronic acid or zoledronate, which is a bisphosphonate. Aclasta is used to treat osteoporosis in postmenopausal women and in men. Aclasta is also used to treat Paget's disease of bone. Aclasta would in turn allow bone remodeling to go back to normal levels and also protecting the bones from being weakened.100 ml of Aclasta is administered through infusion into by a doctor/nurse once a year. The infusion will last 15mins. Precautions.Risk of severe renal impairment. Appropriate hydration is important prior to administration &adequate calcium and vitamin D intake prior to Aclasta therapy in patients with preexisting hypocalcaemia, and for 10 days following Aclasta in patients with Paget's disease of the bone. Monitor for other mineral metabolism disorders; avoid invasive dental procedures for those who develop osteonecrosis of the jaw.Side Effects: bone, muscle, or joint pain, dizziness, fever and chills, flu-like symptoms (fever, chills, bone pain, or muscle and joint pain),headache, heartburn, nausea, tiredness.

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