Deficiencies, Diseases, Disorders, Oh My!

There are many deficiencies, diseases, disorders associated with the skeletal system. Here are a few:

Osteoporosis | Bone Cancer | Arthritis | Rickets | Leukemia


Osteoporosis is one disease of the skeletal system. It is characterized by an abnormally high decrease in the amount of bone tissue in the skeleton (see picture below). This decrease in bone mass substantially reduces the amount of strength that bones have. These brittle bones are far more susceptible to fracture than strong bones. Osteoporosis is usually clinically "silent" until a fracture occurs. Decreased bone mass is one of the leading causes of bone fracture in the country.

Normal bone tissue      Bone tissue with osteopororsis

The key to understanding osteoporosis lies in understanding that bones are constantly being "remodeled" by cells. In the body there are two specialized hormones for this remodeling. Osteoblasts are responsible for the formation of new bone. Osteoclasts reabsorb old bone. During childhood, formation by osteoblasts dominates, and bone mass increases. At adulthood, the amount of bone formation and resorbtion is about equal. At middle-age, resorbtion exceeds formation and bone mass decreases. If one has not obtained a certain amount of bone mass by middle age, he or she could develop osteoporosis.

Several factors have roles in determining susceptibility to osteoporosis. First, women are at a much higher risk than men. Because of the fact women have smaller bones than men, they are more likely to suffer the consequences of bone loss. Women are also at a higher risk because they lose the bone-building mineral during menstruation and lose the hormone estrogen, which helps increase bone mass, after menopause. Another factor that increases the chances of getting osteoporosis is lifestyle. Physical inactivity, cigarette smoking, and an unhealthy diet low in calcium can increase one's risk of bone loss. Next, race often affects the probability of someone developing osteoporosis. For unknown reasons, people of European or Asian descents are more susceptible than people of African or Latin ancestry. Other factors include a small body frame and the use of certain medications.

To avoid osteoporosis, those in high risk groups should take preventative measures. Although the maximum bone mass one can acquire is usually genetically predetermined, one can take steps to obtain as much bone mass as possible during the teens and twenties. A healthy diet, including a high calcium intake, and exercise help increase bone mass. Smoking and drinking should be avoided.

There are several treatment options for those afflicted with osteoporosis. First, hormone-replacement therapy has been proven beneficial, especially for post-menopausal women. This treatment uses estrogen and/or progesterone to decrease mineral loss after menopause. Although estrogen has been shown to increase the risk of breast and uterine cancer, when it is combined with progesterone the chances of uterine cancer decreases. For women at high risk for breast cancer, another treatment option if calcitonin. Calcitonin is a hormone produced by the thyroid gland that inhibits osteoclasts. Though calcitonin initially increases bone mass, long-term and continuous administration can actually have the reverse effect, decreasing bone mass. Calcitonin is also very expensive. Other possible treatments include calcium supplements, vitamin D supplements, fluorides, and (in men) testosterone or anabolic steroids.

Bone Cancer

Bone cancer is another disease of the skeletal system. It may originate in the bones or spread there from another part of the body. Only about one percent of cancer cases in the country is bone cancer. It usually occurs in people under the age of twenty. Most of the cases found in older adults have been spread from elsewhere in the body. The symptoms of bone cancer are a localized swelling and a dull ache. Because it has such symptoms, bone cancer is often mistaken for a bruise and is overlooked. Since the symptoms are so easily misinterpreted, the disease is many times not diagnosed until after metastasis has occurred. Prompt surgery, radiation, or chemotherapy treatment usually leads to complete recovery.


Arthritis is a group of more than one hundred inflammatory diseases that damage joints and their surrounding structures. The most common symptoms of arthritis include pain, some disability, and inflammation. Arthritis may be located in joints, joint capsules, the surrounding tissue, or throughout the body. It usually affects the joints of the neck, shoulders, hands, lower back, hips, or knees. Inflammation in the joints can give adverse effects on other organ or systems.

Around one in six people suffer from one form of arthritis. Arthritis does not discriminate. It can occur in any age group, race, or gender. Certain types of arthritis, however, are found in specific groups of people.

The causes of arthritis vary. In young people it often occurs as a result of trauma, infections, or a rheumatic or immune reactions. Arthritis can also be genetic. The Reiter's and Sjogren's forms have been shown to run in families. Metabolic disturbances can lead to arthritis because, as a result of these disturbances, uric acid is deposited in the skin and joints. Some forms of arthritis, primarily localized ones, may be bacterial, viral, or fungal. Tumors can also result in arthritis. Tumors in blood vessels, cartilage, and synovial or nerve tissue may bring on some form or another. Other causes include blood abnormalities, sports injuries, obesity or the wear and tear associated with old age.

A few types of arthritis are more common than others. Osteoarthritis is one major form. It is caused by irregular bone growth at the edge of a joint. Osteoarthritis is degenerative and occurs late in life. Characterized by disabling stiffness, it often leads to impaired movement and pain caused by pressure on nerves in the area. Another very common form of arthritis is rheumatoid arthritis begins with a gradual erosion of cartilage. After a period of time it can completely destroy a joint cavity and lead to the fusion of the bones.

Rheumatoid Arthritis

Most forms of arthritis can be prevented through exercise and good health habits. The treatment of arthritis ranges from over-the-counter medications to surgery or hospitalization.


Rickets is a nutritional disorder found in children that leads to skeletal deformities. The disease comes about as a result of a low amount of vitamin D, calcium, and phosphorous, all of which are vital to bone development. Rickets is characterized by the improper hardening or development of bones. It often leaves children with bowed legs, swollen joints, muscle pain, a curved spine, or a swollen skull due to softened bones. Preventing rickets is easily accomplished through vitamin D supplements and moderate exercise. Treatment includes diet modification, exercise, and avoidance of excessive sleep.


Leukemia is a cancer influenced heavily by the skeletal system. Although it is a condition that primarily affects the blood, leukemia is still associated with the skeleton because it begins in the marrow of the bone.

Blood cell development, or hematopoiesis, begins with immature stem cells in marrow which may produce any of the three types of blood cells (erythrocytes, leukocytes, and thrombocytes). Molecules called growth factors act upon them, and they divide rapidly, becoming blast cells. The blast cells eventually become one of the three blood cell types.

In a person without leukemia all cell types maintain a relatively constant level. In leukemia patients, however, there is a dramatic increase in the number of leukocytes produced. Cancerous leukocytes are not able to fight disease like normal leukocytes. The bone marrow becomes crowded with abnormal leukocytes, leading to a decrease in the production of red blood cells and platelets. A lack of these blood cells leads to weakness and profuse bleeding. Patients of leukemia are very susceptible to infections because of the decrease in normal leukocytes. Leukemia can also lead to disfunctions of various organs due to accumulations of abnormal leukocytes in the blood.

The exact causes of leukemia are unknown, but there are many factors that have empirically been shown to increase one's risk of getting the disease. Several environmental factors, including certain chemicals and radiation, may cause leukemia.

Treatment for leukemia is limited by the spread of the cancerous cells. Unlike in most cancers, surgery and radiation are not effective because abnormal leukocytes usually have spread through the blood stream before diagnosis. Thus, doctors must find other alternatives. The two best options for treatment are chemotherapy and bone marrow transplant. Chemotherapy uses chemical agents to kill leukemic cells. Unfortunately, chemotherapy kills normal cells as well, leaving the patient extremely ill. For those unresponsive to chemotherapy, a bone marrow transplant is often the last hope. A bone marrow transplant replaces diseased marrow with normally functioning stem cells from a donor, usually a sibling. If all goes well during the transplant, the production of normal cells ensues. Due to the success of chemotherapy and bone marrow transplants, the chance of surviving leukemia is above ninety percent.

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