Osteomalacia is a weakening of the bones due to problems with bone formation or the bone building process. It is not the same as osteoporosis, which is a weakening of living bone that has already been formed and is being remodeled.
The most common reason that osteomalacia occurs is a lack of vitamin D. Vitamin D is an important nutrient that helps you absorb calcium in the stomach. Vitamin D also helps maintain calcium and phosphate levels for proper bone formation. It is made within the skin from exposure to UV rays in sunlight, and it can also be absorbed from foods such as dairy products and fish.
Low levels of vitamin D mean that you cannot process calcium for use in your bones to give them structural strength. This can result from either a problem with diet, lack of sun exposure, or a problem with your intestines.
If you have had surgery to remove parts of your stomach or small intestine, you may also have a problem absorbing vitamin D or breaking down food to release vitamin D. Conditions that can interfere with the absorption of vitamin D include:
- celiac disease, which can damage the lining of your intestines and prevent the absorption of key nutrients like vitamin D
- certain types of cancer that can interfere with vitamin D processing
- kidney and liver disorders that can affect the metabolism of vitamin D
A diet that doesn’t include phosphates can result in phosphate depletion, which can also lead to osteomalacia.
Certain drugs, such as phenytoin and phenobarbital, used to treat seizures, can also cause osteomalacia.
Bones that fracture very easily are the most common symptom of osteomalacia.
Another symptom is muscle weakness due to problems at the location where the muscle attaches to bone. You may have a hard time walking and may develop a waddling gait.
If you have very low levels of calcium in your blood, you may have irregular heart rhythms. Low blood calcium may also cause numbness around the mouth or in your arms and legs, and spasms in your hands and feet.
Blood tests to check for low levels of vitamin D, calcium, and phosphorus in your blood can help diagnose osteomalacia and other bone disorders. You may also be tested for alkaline phosphatase isozymes. High levels of these indicate osteomalacia. Another blood test can check your levels of parathyroid hormone, high levels of which are associated with insufficient vitamin D and other related problems.
X-rays and other imaging tests can reveal small cracks in the bones throughout your body. These cracks are called Looser’s transformation zones. These cracks are where fractures can begin with even small injuries.
A bone biopsy may be required to definitively diagnose osteomalacia. A needle is inserted through your skin and muscle and into your bone to obtain a small sample. That sample is put on a slide and examined under a microscope. Usually, an X-ray and blood tests are sufficient to make a diagnosis, and a bone biopsy is not necessary.
If detected early, treatment can be as simple as taking oral supplements for vitamin D, calcium, or phosphate. If you have absorption problems due to intestinal injury or surgery, or have a diet low in key nutrients, this may be the first line of treatment. In rare cases, vitamin D may be administered as an injection through the skin, or intravenously through a vein in your arm.
You may also be asked to spend some time outdoors in sunlight for your body to make sufficient vitamin D within your skin.
If you have other underlying conditions that affect vitamin D metabolism, they need to be treated. Liver cirrhosis and kidney failure must be treated to reduce osteomalacia.
Children may have to wear braces or have surgery to correct bone deformation in severe cases of osteomalacia or rickets.
If left untreated, osteomalacia will lead to many broken bones and severe injury. With an increase in vitamin D, calcium, and phosphorus, improvements can be seen in a few weeks. Complete healing of the bones takes about six months.
Symptoms can return if sufficient vitamin D is not available because supplements are discontinued or underlying health conditions, such as kidney failure, are not addressed.