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Osteomalacia

Osteomalacia is softening of the bones. It most often occurs because of a problem with vitamin D, which helps your body absorb calcium. Your body needs calcium to maintain the strength and hardness of your bones.

In children, the condition is called rickets.

Causes

A lack of the proper amount of calcium leads to weak and soft bones.

Vitamin D is absorbed from food or produced by the skin when exposed to sunlight. Lack of vitamin D produced by the skin may occur in people who:

  • Live in climates with little exposure to sunlight
  • Must stay indoors
  • Work indoors during the daylight hours
  • Wear clothes that cover most of their skin
  • Have dark skin pigmentation 
  • Use very strong sunscreen

You may not get enough vitamin D from your diet if you:

  • Are lactose intolerant (have trouble digesting milk products)
  • Do not eat or drink milk products (more common in older adults)
  • Follow a vegetarian diet
  • Are not able to absorb vitamin D well in the intestines, such as after gastric bypass surgery

Other conditions that may cause osteomalacia include:

  • Cancer
  • Kidney failure and acidosis
  • Lack of enough phosphates in the diet
  • Liver disease, and therefore cannot convert vitamin D to its active form
  • Side effects of medicines used to treat seizures

Symptoms

Symptoms include:

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

Exams and Tests

Blood tests will be done to check vitamin D, creatinine, calcium, phosphate, electrolytes, alkaline phosphatase, and parathyroid hormone levels.

Bone x-rays and a bone density test can help detect pseudofractures, bone loss, and bone softening. More importantly, osteomalacia can look like weakening of the bones from osteoporosis on bone density testing.

In some cases, a bone biopsy will be done to see if bone softening is present.

Treatment

Treatment may involve vitamin D, calcium, and phosphorus supplements taken by mouth. People who cannot absorb nutrients well through the intestines may need larger doses of vitamin D and calcium. This includes people who have some types of weight loss surgery.

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 get better within a few weeks. With treatment, healing should happen within 6 months.

Possible Complications

Symptoms can return.

When to Contact a Medical Professional

Call 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 and calcium can help prevent osteomalacia due to a vitamin D deficiency.

Alternative Names

Vitamin D deficiency - osteomalacia; Calcium - osteomalacia

Images

References

Bringhurst FR, Demay MB, Kronenberg HM. Hormones and disorders of mineral metabolism. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology. 13th ed. Philadelphia, PA: Elsevier; 2016:chap 28.

Demay MB, Krane SM. Disorders of mineralization. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 71.

Weinstein RS. Osteomalacia and rickets. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 244.

Review Date 5/2/2016

Updated by: Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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