Osteomalacia Health Article

Definition

Osteomalacia is softening of the bones due to a lack of vitamin D or a problem with the body's ability to break down and use this vitamin.

Causes, incidence, and risk factors

The softer bones seen in persons with osteomalacia have a normal amount of collagen, which gives the bones its structure, but lack the proper amount of calcium.

There are numerous causes of osteomalacia. In children, the condition is called rickets and is usually caused by low levels of vitamin D.

Other conditions that may lead to osteomalacia include:

• Not enough vitamin D in the diet
• Not enough exposure to sunlight, which produces vitamin D in the body
• Malabsorption of vitamin D by the intestines

Use of very strong sunscreen, limited exposure of the body to sunlight, short days of sunlight, and smog are factors that reduce formation of vitamin D in the body. The elderly and those who avoid drinking milk are at increased risk for osteomalacia.

Other conditions that may cause osteomalacia include:

• Cancer
• Hereditary or acquired disorders of vitamin D metabolism
• Kidney failure and acidosis
• Liver disease
• Phosphate depletion associated with not enough phosphates in the diet
• Side effects of medications used to treat seizures

Symptoms

• Bone fractures that happen with very little injury
• Muscle weakness
• Widespread bone pain, especially in the hips

Symptoms may also occur due to low calcium levels. These include:

• Abnormal heart rhythms
• Numbness around the mouth
• Numbness of arms and legs
• Spasms of hands or feet

Signs and tests

Blood tests will be done to check vitamin D, creatinine, calcium, and phosphate levels.

A bone biopsy reveals bone softening.

Bone x-rays and a bone density test can help detect pseudofractures, bone loss, and bone softening.

Other tests may be done to determine if there is a kidney problem or other underlying disorder. These tests include:

• ALP (alkaline phosphatase) isoenzyme
• PTH