Wednesday, August 31, 2011

Keeping to myself....



Sometimes, things are better exposed to let other people know. The term 'sharing' is always misused. Some people prefer to share everything that they have to the whole world. Feeling that they are the happiest or the most gifted creature in the entire universe. Some people things that, there are things that are better to be kept quiet or at least not to be told purposely. Sharing something could be a pleasure for some people but not for others. Its human nature to feel envy or intimidated by stuffs that are not belong to them .We could not deny that because part in our heart has been filled with all those negative elements. Now, lets be more grateful. And I hope that I can always do something that would satisfy myself but not to make everyone satisfied. It is impossible to make it happen. Things that are better kept to myself would remain in my little hippocampus until I thought it is appropriate to share..


Friday, August 12, 2011

Osteoporosis



Introduction

Osteoporosis is characterized by decreased bone strength. The prevalence of this disease is high in post menopausal women and in men or women with underlying or major risk factors that are associated with bone demineralization. Vertebral and hip fractures are the chief complaint but other sites can also be affected.


Definition

Osteoporosis is defined as decrease in the bone strength leading to an increased risk of fracture. Deterioration of micro architecture of the bone lead to the osteoporosis. The WHO defines osteoporosis as a bone density that falls 2.5 standard deviations below the mean of young healthy adult of the same gender.



Pathophysiology

Modelling and remodelling are two different terms need to be explored before we further discuss about osteoporosis. Basically, modelling is the apposition of new bones tissues on the outer surface of the cortex. This process allows long bones to adapt in shape in response to the stress place upon them. There are many factors that have important roles in bone growth such as genetics, sex hormones, nutrition and lifestyles. The primary determinant is genetic that determine the peak bone mass and its density. Se hormones are important for skeletal maturation of bone as well as sexual dimorphism appearance. Genetic studies produce different results. One of the studies stated that a point mutation in LRP-5 is associated with high bone mass without much apparent of age-related bone loss.

Remodelling process is the principle metabolic function in adult since its function is to repair micro-damage as well as to maintain the balance of calcium serum level. There are systemic factors such as PTH, androgen, estrogen, vitamin D as well as local factors including insulin-like growth hormone I and II, transforming growth factors β, members of TNF superfamily (RANKL), prostaglandins, ILs and parathyroid hormone related peptide (PTHrP), that modulate the process. Basically, RANK ligand is an important cytokines for the communication between osteoblast, other marrow cells and osteoclast. Osteoclast posses RANK receptor for the development and activation. This receptor is activated by RANKL. Moreover, osteoblast also produce osteoprotegerin (OPG) that can bind to RANKL to neutralize this factor.

When we get older, there are an increased in osteoclastic activity and/or decreased in osteoblastic activity that results in net loss of bone mass. The increased in remodelling site can increase the likelihood of trabeculae penetration by osteoclast that leave no template for bone formation. This would impair the cancellous connectivity. More porous bone can occur if the cortical part of the bone undergo remodelling.


Risk Factors

a. Calcium Intake

Basically, calcium as well as other nutrition such as proteins, calories and other minerals is needed for optimal growth of skeleton. The insufficiency of calcium leads to secondary hyperparathyroidism. PTH secreted lead to the increased in bone remodelling to maintain the balance level of serum calcium. Other than that, PTH stimulates hydroxylation of vitamin D in the kidney. Moreover, it can lead to the increased gastrointestinal calcium absorption. PTH also reduces renal calcium loss. On the other hand, the prolonged effect of this hormone is detrimental because it can lead to increased risk of osteoporosis.

b. Vitamin D

Vitamin D inadequacy is also dangerous because it can lead to secondary hyperthyroidism. The insufficiency of Vitamin D can be due to many factors such as the elderly, people living in northern latitudes, and people with poor nutrition, malabsorption and chronic renal or liver failure. Dark-skinned people are also at increased risk of vitamin D deficiency. The recommended amount of daily vitamin D intake is 800-1000 unit in order to maintain optimal level of 25(OH)D at > 75nmol/L (30ng/ml).


c. Estrogens

Basically, estrogens plays a very important part in bone metabolism in women. Bone cells (osteoblasts, osteocytes, and osteoclast) as well as marrow cells (monocytes, macrophages, mast cells and osteoclast precursors) expresses ERs α and ERS β. Lack of estrogens leads to the decreased of osteoblast life span and the increased longevity and activity of osteoclast. Basically, this leads to increased in activation sites of remodelling as well as the net loss of bone mass. The likelihood of trabeculae penetration increases. As we know that, the trabeculae contribute around 80% of total surface area, the destruction can accelerate osteoporosis and fractures. Since vertebral parts have depends mostly on trabeculae for the strength, this fractures is the most common early consequence of estrogen deficiency.


d. Chronic diseases

Endocrine disorder such as diabetes mellitus type I, adrenal insufficiency, thyrotoxicosis, Cushing’s syndrome, hyperparathyroidism and acromegaly are some of the causes of the risk factors of OA. Other factors include hypogonal states such as Turner syndrome, Klinefelter syndrome, anorexia nervosa and thalassemia; rheumatologic disorders such as rheumatoid arthritis and ankylosing spondylitis; and many more can lead to an increased risk of osteoporosis.

e. Medication

Other than disease itself that can lead to bone loss, the use of certain medication can somehow lead to osteoporosis. One of the well-known drugs is glucocorticoids. Other than that, excessive thyroid hormone can increase bone remodelling and bone loss. Some anticonvulsant can lead to deficiency of 1,25(OH)2D because it can increase the activity of Cytochrome P450 and increase vitamin D metabolism. This can increase the risk of osteoporosis. Patients who undergo transplantation are at risk of developing osteoporosis not only due to the use of glucocorticoids but also because of the use of other immunosuppressants such as cyclosporine and tacrolimus. Furthermore, these patients might have other underlying metabolic diseases such as renal or hepatic failure. Aromatase inhibitor can inhibit the conversion of androgens or other adrenal precursors to estrogen to low level.

f. Cigarette Smoking

Smoking has direct toxic effect on osteoblast and indirect effect on osteoblast by modifying metabolism of estrogen. Moreover, smoking can develop secondary effects that can modulate skeletal status such as intercurrent respiratory or other illnesses, poor nutrition, lack of exercise and the need of additional medication such as glucocorticoids for lung disease.

Treatment

a. Management of Osteoporotic Fracture
Basically, acute fracture due to osteoporosis often needs management of the bone fractures and the treatment of underlying disease. The surgical intervention depends on many factors including location. Usually, long bones fractures frequently need either internal or external fixation. Hip fracture is one of the examples of the fractures that need surgical intervention. There are some factors needs to be considered before performing different types of surgical method (open reduction and internal fixation with pins and plates, hemiarthroplasties or total arthroplasties) including the location and severity of the fracture, general status of the patients and the condition of neighbouring joint. The others such as vertebral, ribs and pelvis fractures usually require no specific orthopedic intervention but only supportive management.

Some patient with acute vertebral compression fractures present with sudden onset back pain. This often requires analgesics such as NSAIDs, acetaminophen or narcotics depending on the needs. Percutaneous injection of vertebral body with cement (polymethylmethacrylate) might provide instant pain relief in majority of the pain as proven by a few small randomized clinical trials. Short periods of bedrest is helpful for pain management in early mobilization is required to prevent further bone loss. Occasionally, in order to facilitate early mobilization, an soft elastic-style brace can be used. Muscle spasm can be managed by using muscle relaxants and heat treatments.

Pain usually resolves within 6-10 weeks. Chronic pain is difficult to manage. The pain is usually is originated from ligament, muscle or tendon that are strained or due to secondary facet joint arthritis. This condition can be managed by analgesic, heat treatment, ultrasound, transcutaneous nerve stimulation back strengthening exercise, intermittent rest in supine and semi-reclining postion as well as family support and psychotherapy.

b. Risk Factor Reduction

The risk factors associated with bone loss and falling must be evaluated thoroughly. Smoking cessation is indicated if a person smoke. The review of glucocorticoids treatment is also important. TSH must be evaluated in people on thyroid replacement therapy as thyrotoxicosis is associated with increased bone loss. Measures to reduce the risk of falling such as treatment of nocturia, alcohol abuse therapy, the review of medical treatment that is related to orthostatic hypotension or sedation, and other preventive measures are indicated. Preventive measures such as eliminating exposed wires, curtain strings, slippery rugs, mobile table, avoiding of stockings feet on wood floor, and providing good lights in path to bathroom and outsides the house are essential for risk reduction.

c. Nutritional Recommendation

Two important supplements are calcium and vitamin D. Calcium can be obtained from various sources such as dairy milk. Basically, if 600mg or more need to be taken, it should not be taken at the time since high dose of calcium will decrease the absorption fraction. Vitamin D should be taken according to the age; 200 IU for people < 50 years old, 400 IU for people between 50 to 70 years old, and 600 IU for people more than 70 years old.