Osteomalacia

Causes

The softer bones in osteomalacia have a normal amount of collagen, which gives the bones its structure. However, they lack the proper amount of calcium.

There are many 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

Factors that reduce formation of vitamin D in the body include:

• Having very little exposure to sunlight
• Shorter days of sunlight
• Smog
• Using very strong sunscreen

The elderly and people who do not drink milk are at increased risk for osteomalacia.

Other conditions that may cause osteomalacia include:

• Cancer
• Disorders of vitamin D metabolism
• Kidney failure and acidosis
• Lack of enough phosphates in the diet
• Liver disease
• Side effects of medications used to treat seizures

Symptoms

• Bone fractures that happen without a real injury
• Muscle weakness
• Widespread bone pain, especially in the hips

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

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

Exams and Tests

• Blood tests will be done to check vitamin D, creatinine, calcium, and phosphate levels.
• Bone biopsy will show 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 find out if a kidney problem or other disorder is causing the problem. These tests include:

• ALP (alkaline phosphatase) isoenzyme
• PTH

Treatment

Treatment may involve vitamin D, calcium, and phosphorus supplements taken by mouth. People who cannot properly absorb nutrients through the intestines may need larger doses of vitamin D and calcium.

People with certain conditions may need regular blood tests to monitor blood levels of phosphorus and calcium.

Outlook (Prognosis)

Some people with vitamin deficiency disorders will see improvement within a few weeks. You should heal completely with treatment in about 6 months.

Possible Complications

Symptoms can return.

When to Contact a Medical Professional

Call for an appointment with your health care provider if you have symptoms of osteomalacia, or if you think that you may be at risk for this disorder.

Prevention

Eating a diet rich in vitamin D and getting plenty of sunlight can help prevent osteomalacia due to a vitamin D deficiency.

References

Wysolmerski JJ, Insogna KL. The parathyroid glands, hypercalcemia, and hypocalcemia. In: Kronenberg HM, Schlomo M, Polansky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 11th ed. St. Louis, Mo: WB Saunders; 2008:chap 266.

Bringhurst FR, Demay MB, Kronenberg HM. Disorders of mineral metabolism. In: Kronenberg HM, Schlomo M, Polansky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 11th ed. St. Louis, Mo: WB Saunders; 2008:chap 27.

Sysolmerski JJ, Insogna KL. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 253.

Update Date: 7/19/2012

Updated by: Shehzad Topiwala, MD, Chief Consultant Endocrinologist, Premier Medical Associates, The Villages, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.