Osteomalacia is a condition in which the bones lose calcium and become softer. (When osteomalacia occurs in children, it's called rickets.) As the bones get softer and more flexible, they are affected by the weight they carry or other forces put on them. This causes the bones to deform.
Osteomalacia is marked by a variety of symptoms including:
- Difficulty walking up stairs or getting up from a chair
- Frequent bone fractures with little cause
- Generalized pain that may not affect any particular part of the body. Sometimes it is experienced a stiffness. Sometimes it can be due to slight cracks in bones that can be seen on X-rays.
- Weak thigh and arm muscles
Causes and Risk Factors
There are two common causes of osteomalacia:
- The body can't absorb fat properly due to a digestive disorder. This is called steatorrhea. Fats are passed directly out the body in the stool. As a result, vitamin D, which is usually absorbed with fat, and calcium are poorly absorbed.
- The kidneys don't work properly. As a result of this, there is more acid in body fluids. Called tubular acidosis, this increased acid gradually dissolves the skeleton.
A third, less common cause of osteomalacia is digestive problems that keep the body from absorbing calcium properly. In the United States, osteomalacia and rickets rarely occur because of a lack of vitamin D. Most milk is supplemented with vitamin D. Additionally, the skin makes vitamin D after getting even a little sunlight. However, if you or your child has trouble digesting milk products, your doctor may advise taking vitamin D supplements to prevent a lack of vitamin D. A long-term lack of calcium in the diet also can result in osteomalacia, but it usually causes osteoporosis. There is also a hereditary form of rickets often called vitamin D-resistant rickets. (In this case, a person doesn't grow to full, typical adult height.)
The amounts of calcium and phosphorus in the body can be measured with a blood test. Your doctor may also order X-rays of the affected bones. In rare cases, a small sample of bone tissue may be taken. The bone same is then looked at under a microscope to confirm osteomalacia or rickets.
Once osteomalacia is diagnosed, the next step is to learn what has caused it.
Treatment is usually directed to correct the underlying problem. Calcium and vitamin D supplements may be needed. In extreme cases, particularly in vitamin D-resistant rickets, skeletal deformities may require surgical correction. Options include joint replacement, removing tumors associated with Paget's disease and correcting deformities.