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.
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:
- 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
- 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 level. These include:
- Numbness around the mouth
- Numbness or tingling of the arms and legs
- Spasms or cramps of the hands or feet
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 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.
Some people with vitamin deficiency disorders will get better within a few weeks. With treatment, healing should happen within 6 months.
Symptoms can return.
Call your health care provider if you have symptoms of osteomalacia, or if you think that you may be at risk for this disorder.
Eating a diet rich in vitamin D and calcium and getting sufficient exposure to sunlight can help prevent osteomalacia due to a vitamin D deficiency.
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-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 244.