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METABOLIC BONE DISEASES


Bone mineral density
Bone mineral density (BMD) has an inverse relationship between fractures. Even if low BMD is an important predictor of fracture risk in the people with no fracture, there are other factors affecting fracture formation.  
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Still recommended method in measurement of bone mineral density (BMD) is dual x-ray absorbtiometry. (DXA). DXA and BMD measurement is useful in not only diagnosis but also determination of fracture risk and starting and monitoring pharmacological treatment.

BMD Measurement Indications

 • All women over 65 and all men over 70 years of age
 • Young postmenopausal women with risk factor for fracture and men between 50-69 years of age
 • Frequent and quick fractures
 • Minimum 3 months ≥5 mg/day of prednisone or equivalent steroid use
 • Smoking
 • Increased consumption of alcohol
 • Low body mass index (<20 kg/m2) or major weight loss
 • Rheumatoid arthritis
 • Disease history of associated with osteoporosis
 • History of high risk drug use in terms of osteoporosis
 • Fracture presence in direct graphy
 • Hypogonadism or premature menopause

Osteoporosis (Bone Thinning)
This is the most frequently encountered metabolic bone disease characterized by bone fragility and predisposition to fragility as a result of low bone mass and disruption of microarchitecture structure of bone. 

Generally there are 3 types of osteoporosis. 

Premenopausal Osteoporosis: This is an osteoporosis seen in women before menopause.
Postmenopausal Osteoporosis: This is an osteoporosis associated with deficiency of estrogen in postmenopausal period.
Male Osteoporosis: This is a bone disease in men associated with increased fracture risk and low bone mass characterized by increased bone fragility and disruption of bone microarchitecture.

Osteoporosis Symptoms
In early period there are no obvious symptoms of osteoporosis. There is no finding in the beginning in osteoporosis after menopause. More than 30% of bones can be lost within 3-5 years following menopause. If osteoporosis is fully formed, back and lower back pain, hogging and shortening in height can be seen. Particularly, bones of the vertebrae are affected from this type of osteoporosis and fractures are frequently present on these bones. This structural degradation is characterized by shortening in height. In addition, hand wrist bones are also affected by this disease. Findings are characterized by pain in osteoporosis emerged in older people. In exacerbated cases, hip bone fractures can be seen. 

Osteoporosis Treatment
Core of treatment is made up of elimination of risk factors, physical therapy rehabilitation and medical treatment. Purpose here is to stabilize and increase bone mineral density, to prevent fractures, to improve symptoms associated with skeletal deformities and to enhance life quality.

Balanced diet, sufficient calcium and protein intake, physical activity, abstaining from excessive alcohol and smoking are the factors boosting success of treatment. Load imposing exercises to skeleton should be given for continuing and increasing bone mineral density. In addition, flexion exercises should not be done and extension exercises should be emphasized.
Physical treatment modalities such as appropriate positioning, bed resting and TENS, hot pack, infrared as well as analgesics are used in treatment of acute pains. Appropriate orthotics are used for fixing kyphotic posture in chronic pain. But, period of use should be well-adjusted since it may lead to muscle weakness and back extensor strengthening exercises should be given together with this. Again, in this period, analgesic effective physical therapy modalities can be used.

Vitamin D 
Vitamin D is a hormone in secosteoid structure.  Vitamin D level is low in food except for nutrition not strengthened with Vitamin D and this cannot meet daily requirement. 

Vitamin D is synthesized in the skin from ultraviolet radiation. Direct sun radiation to the skin is required for synthesis. Since appropriate beam angle is available at 10:00 a.m. 03:00 p.m., if sunbathing is made between these hours, Vitamin D can be synthesized. It should not be sunbathed behind window and gauze. While minimum melting dose is reached in 15 minutes in a person with fair skin colour, this can be 3-4 times in a person with dark skin.

Vitamin D Deficiency
Vitamin D state according to serum 25 (OH) levels:
>30 ng/ml sufficient 
20-30 ng/ml Vitamin D insufficiency
<20 ng/ml Vitamin D deficiency  
<10 ng/ml serious deficiency

Most of Vitamin D deficiency is generally asymptomatic. Clinic findings are associated with a decrease in calcium in deep and extended Vitamin D deficiency. This case is characterized by numbness, tetany, and convulsions. Decrease in bone density, osteoporosis, osteomalacia , bone and muscle pains, muscle weakness and imbalance are the main findings. 

Primary causes of Vitamin D metabolism are; living in areas near the Poles (33rd parallel top in Northern Hemisphere), lack of sun exposure, dark skin, ageing, sun protective creams with high factors, obesity, increase of Vitamin D metabolism (hyperparathyroidism, lymphoma), malabsorption, nephrotic syndrome-chronic renal failure and various drugs.