A B C D E F G H I J K L M N O P R S T U V W

OSTEOPOROSIS

What is Osteoporosis ?

Bone is made up of two types of tissue. First there is a protein network which forms the structure for the bone. Secondly, there are calcium salts which are deposited and reinforce the protein network to give the bone its strength. Osteoporosis is a condition where both the protein network and the calcium salts are deficient. This makes the bone softer. There may be very few symptoms until about one-third of the bone strength is lost. Then pain occurs due to distortion and fracture of the bone. It is usually in the spine, which carries the major weight load. One or more vertebrae of the spine may collapse completely, giving acute pain and later shortening of the spine. The deformity is responsible for some cases of so-called dowager's hump. Wrist and hip fractures are more likely to occur in people with osteoporosis, especially in patients beyond the age of 65. They are mostly brought about by a minor fall or injury, which alone would not cause fractures in otherwise healthy people.

How does Osteoporosis occur ?

Osteoporosis is a gradual process which may start as long as 20 years before the first symptom appears. It may result from generally poor diet, especially one which is low in calcium. It may also come from long periods of bed-rest, such as might occur with severe or prolonged illness. The pull of muscles, in ordinary body movements and particularly regular exercise, is now known to be an important way of keeping bones strong. Many cases result simply from ageing. From the age of 35, most people have a gradual reduction in their bone strength. It is the strength of bone at this age which partly decides whether the bone loss which occurs with ageing will lead to serious bone thinning or not. Some people lose bone strength (calcium) faster as they age; others lose much less. The sex hormones (oestrogens in women, androgens in men) protect the bones to some extent from this ageing effect. For this reason, after menopause, women lose bone rather more rapidly than they did before the menopause. They also lose bone faster than men. It is therefore post-menopausal women who are at greatest risk from osteoporosis. A menopause which occurs earlier than usual (for example, after removal of the ovaries) is particularly likely to result in osteoporosis. The absent periods of some women athletes and in people with the condition of anorexia nervosa also cause bone to be lost. Some disorders, like multiple myeloma, overactive thyroid and overactive parathyroid glands, can also produce general thinning of the bones. These are most important to identify, because treatment of the cause will correct the osteoporosis. Drugs called steroids (cortisone-like drugs) are used in many conditions. Asthma, arthritis and certain skin and bowel conditions are the main ones. If used for more than a few weeks, they can cause osteoporosis, which many not necessarily fully recover when the steroids are stopped.

Why does Osteoporosis occur ?

There is almost certainly a hereditary factor. Many people with osteoporosis give a history of this condition in one of their parents. However, the exact nature of this hereditary factor is unknown. The two things which lead to common osteoporosis are a reduced bone strength at the peak of maturity (approximately age 35), and the rate at which calcium is lost from the bones during the next 20 to 50 years. Afro-Caribbeans are less likely to get osteoporosis than either Caucasians or Asians.

Treatment Involved for Osteoporosis

DIAGNOSIS Blood and urine tests may be needed. The density of bone can be measured using special x-ray, ultrasound or radioactive isotopes ( DEXA scan) . ). Bone density measurement (bone densitometry) makes it possible to pick up « thin bones » well before they cause symptoms. Occasionally a piece of bone (biopsy) is taken from the hip. Analysis may help to assess the severity and the cause of the problem. Tests are done to try to find a cause. Doctors are always careful to exclude osteomalacia. This is another cause of thin bones, in which the protein network is normal, but calcium is not being properly deposited in the bones. It can be effectively treated by giving vitamin D tablets or injections. Sometimes the cause of osteoporosis is obvious (for example, removal of the ovaries at the age of 35). Once osteoporosis occurs, it is possible to prevent worsening of the condition and even to improve the strength of the bone. Treatment may then reduce the likelihood of further bone loss (and fracture).

TREATMENT A high calcium diet is often advised. Sometimes additional calcium-containing tablets are prescribed and there is good evidence that these steps help :.trials show improvement in bone density and reduced fracture rates. Vitamin D may be given as well, to help the calcium get into the bones more efficiently. You will be urged to keep up or develop regular exercise, like daily swimming or walking. Impact exercise is of particular value. Exercise is known to help push calcium back into the bones. Giving sex hormones (hormone replacement therapy: HRT) to women who have low oestrogen levels slows down the rate of bone loss, but does not prevent the bone loss due to ageing itself. DEXA scans are often used to help decide whether HRT should be used. In women with osteoporosis, bone density increases with HRT, up to 2% per year. Not every post-menopausal woman needs HRT for their bones, although HRT has other benefits : there is good evidence that it reduces the risk of heart attacks and strokes. From this point of view, it is wise to start it soon after menopause.. We do not know how long HRT treatment needs to continue. However, as soon as HRT is stopped, there is a tendency for loss to recur. A course of 10 or more years is therefore usually advised. It may be wise to give hormones also to other women who are without periods due to insufficient oestrogen (female hormones).

For some women with certain breast disorders, oestrogens may not be advisable. The drug, raloxifene (Evista) has oestrogen-like benefits on bone, without the other side effects and is therefore useful in this situation. Calcitonin is another hormone which is normally produced by the body. Its function is to keep calcium within the bones. It improves bone density in some patients, and can be used either as injections or by nasal spray. Drugs called bisphosphonates strengthen bone, and are probably the most effective agents for helping calcium into the bones. They can be given as short courses or continuously, by injection or as tablets. There is good evidence of increased bone density after their use. In fact, the drug risedronate has been shown to reduce the risk of s[pinal fractures by 40% over a 3-year period. A recent study showed that alendronate continues to benefit bone even after 7 years of administration. Both bone pain and fracture rates are progressively reduced. Bisphosphonates have also been shown to be effective in preventing osteoporosis when using steroid-type drugs over long periods. Surprosingly, parathyroid hormone (PTH) has been shown to increase calcium content and bone density : this is a paradox since as mentioned above, in the condition of overactive parathyroid, bone density is mostly reduced! It has to be given by injection, and the exact cases who will benefit are not yet clear. At present, prevention and early detection are the best principles of treatment. Once fractures occur, improvement in osteoporosis is certainly possible, but is less effective.

During Treatment for Osteoporosis

Improvement in pain from osteoporosis is never dramatic, whatever the cause or treatment. Some people incorrectly stop their treatment, just because they cannot feel the benefits of it. HRT is usually safe, but in some people can lead to blood clots or high blood pressure. Calcium-containing medicines are usually without side-effects, although the taste is not always to everyone's liking! The other drugs used all have occasional side effects : it is best to report any unusual symptoms. Checking the response of your bones to treatment is important. Bone density needs to be checked every 1 to 2 years : your treatment may need to ne changed if there is no benefit.

After Treatment for Osteoporosis

Further fractures and pain may occur. If these involve the spine, it is sometimes helpful to have some type of spinal support or corset.

If Osteoporosis is Left Untreated

Patients with pain or fracture would be more likely to develop further problems. Osteoporosis without symptoms is more likely to result in pain and fracture later in life.

Effects on Family of Osteoporosis

Chronic pain is always a heavy burden on people close to the patient. They will need to be understanding and provide regular support and help. It may be wise for children of people with osteoposis to have their bone density checked from time to time. The age at which such « screening » should commence is not known.