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

OSTEOMALACIA - RICKETS

What is Osteomalacia ?

Bone has an interesting structure. It consists first of a protein network. In the spaces between the protein strands are calcium salts. Together, these give the bone its strength. Osteomalacia is a condition where the calcium salts are lost from the bone (osteomalacia of adults) , or inadequately deposited (rickets in children): the protein network is usually not affected. The main substance which keeps calcium in the protein network is vitamin D. Accordingly, most cases of osteomalacia are directly or indirectly due to insufficient vitamin D. This substance comes partly from food and partly from the skin (where it is generated by the effect of sunlight). It then has to be processed by the liver and the kidney, before performing its function in the bone. In children with rickets, the deficiency results in poor growth. Soft bones may result in a misshapen chest and skull. The lower limbs may become bow-legged. The development of teeth is delayed, and children become listless and irritable. The bones are fragile and may fracture. Muscles are weak. In adults, osteomalacia may not cause symptoms at all until the disorder is advanced. Pain in the back, hips and limbs is then common. Fractures may occur even after trivial injury. There is muscular weakness. In both adults, but particularly children, the resulting low calcium level in the blood may cause strange hand spasms (called tetany). The fingers are flexed and cannot be straightened.

How does Osteomalacia occur ?

Vitamin D deficiency occurs most commonly as a result of extreme malnutrition, or even a poor or unbalanced diet. Vegetarians are particularly likely to develop it because there is little vitamin D in vegetables. A lack of sunlight, particularly in people with racially dark skin, is a further cause. Also vitamin D may not be absorbed normally, as in certain disorders of the bowel (coeliac disease). It may not be properly processed by a diseased liver. Kidney failure regularly produces osteomalacia because the vitamin D cannot be processed properly.

Why does Osteomalacia occur ?

There are rare inherited forms of rickets where vitamin D does not function properly for a variety of reasons. In some cases, a shortage of the salt, phosphate, causes the osteomalacia. This can be inherited. Otherwise, there are no hereditary or familial factors. Both rickets and osteomalacia are particularly likely to occur in Asians who follow a vegetarian diet and who live in more northern latitudes. Amongst Asian living outside the Asian continent, the incidence of osteomalacia may be as high as 15%. Within Asia, the actual risk is not known.

Treatment Involved for Osteomalacia

If rickets or osteomalacia is diagnosed, further tests must be done to find the cause. This involves blood and urine examinations. Treating the underlying cause is often possible. Otherwise the treatment involves taking vitamin D by mouth or by injection (which only needs to be given once or twice a year). There are different preparations which can be used, but all need to be taken regularly and probably on a lifelong basis. This will help to move calcium back into the bones. Additional calcium tablets are often advised.

During Treatment for Osteomalacia

Children often show dramatic improvement with treatment. Energy and growth return to normal. Deformities of bones improve, but may not return completely to normal. In adults, any pain due to osteomalacia should improve within 2 to 3 months. Gradually strength and well-being improve as well. Calcium and other blood test measurements will be done regularly during treatment as a guide to the dose of vitamin D which needs to be given. Too much vitamin D is a possible danger. Blood-calcium levels may rise, producing kidney damage.

After Treatment for Osteomalacia

Once the osteomalacia or rickets has been cured, vitamin D treatment is still required to keep the calcium content of the bones normal. This will call for regular visits to the doctor so that blood-calcium and perhaps vitamin D levels can be checked and overall wellbeing assessed. There should be no recurrence of the problem, providing vitamin D is taken regularly.

If Osteomalacia is Left Untreated

Untreated, rickets causes progressive disability in children. The resulting weakness makes infection, particularly of the chest, more likely and this can be fatal. In osteomalacia, pains would get worse and fractures would occur. Progressive weakness would lead to a very poor quality of life for you.

Effects on Family of Osteomalacia

The rare hereditary types of osteomalacia may justify screening other relatives. If rickets or osteomalacia develops in Asians, it is often useful to give vitamin D to other members of the family who are likely to be at risk of developing this disorder later in life. The small doses of vitamin D which are used are unlikely to cause long-term side-effects.