Definition and cause
Osteomalacia is a state of depletion of calcium from the body's bones due to lack of vitamin D. Vitamin D enables the body to absorp calcium and phosphate from the gut while limiting the elimination of calcium in the urine and thus maintain an adequate calcium level in the body.
When the body has insufficient levels of calcium in the blood, a hormone is released from the pituitary gland (PTH), which mobilizes calcium from the reserves in the bones. This is a natural mechanism, but if the level of calcium in the bones are constantly depleted the bones may end up being soft and fragile.
Vitamin D is absorbed from the gut from the diet, but the body is also capable of producing its own vitamin D in the skin when it is exposed to sunlight. Osteomalacia can thus occur in the absence of intake of vitamin D e.g. in diseases of malabsorption, where the uptake from the intestine is impaired or in lack of sunlight, for example as seen in some Muslim women, who are completely covered. In chronic renal failure, where vitamin D can not work on the kidneys, osteomalacia may also develop.
Some medications (e.g some anti epilepsy drugs), severe liver disease or removal of large parts of the intestine, can also lead to development of the disease.
In children the disease is called rickets, and the condition is quite frequent in developing countries with malnutrition. In the developed world osteomalacia is relatively rare, but is growing due to an increased number of immigrants with different ethnic origin.
Symptoms of osteomalacia
Osteomalacia is associated with:
Pain from the bones and muscles.
An increased incidence of fractures, but not as great as in osteoporosis (brittle bones).
Slow, limping gait.
There may also be symptoms of a low level of calcium in the blood (convulsions, neurological disorders, heart problems).
Precautions and diagnosis
A key measure is a sufficient intake of vitamin D for example through dairy products and fatty fish, which contains much vitamin D. If you are unable to get enough vitamin D from your diet or from exposure to sunlight, you can supplement with a vitamin D supplement. This may also be given to children in winter in countries on the northern hemisphere.
On an X-ray osteomalacia often resembles osteoporosis, but a blood- and possibly a urine sample will show disturbances of the calcium metabolism, which is not seen in osteoporosis.
The symptoms may also be confused with cancer metastasis to the bone, and if this is suspected one is forced to take a bone biopsy to establish a certain diagnosis.
Treatment of osteomalacia
The treatment of osteomalacia aims to restore the body's vitamin D depots. Often vitamin D tablets are sufficient.
Bone deformation can usually not be reversed and will be permanent. If you simultaneously have been diagnosed with osteoporosis (by e.g. a bone scan), you should be scanned again after treatment with vitamin D, as osteoporosis often is improved by the osteomalaci treatment.