About Osteomalacia and Rickets
Osteomalacia is a disorder marked by inadequate or defective mineralization of the skeleton, resulting in soft or fragile bones. It typically occurs either when there are insufficient amounts of vitamin D in the diet or, more commonly, when the body is unable to properly absorb and metabolize vitamin D, which is essential for the absorption of the calcium needed to maintain strong, healthy bones. It can also occur with calcium and phosphorus deficiency.
When the disease occurs in children, it is known as rickets and tends to produce obvious skeletal deformities. The disease has more subtle manifestations in adults and may be difficult to diagnose or to differentiate from osteoporosis. In some cases repeated pressure on soft bones can lead to fractures or mild deformities.
In adults, when osteomalacia is due to a vitamin D deficiency, treatment usually cures the problem within six months. In children, the disease may be arrested, although skeletal deformities may be permanent. Although common in underdeveloped countries, rickets is now rare in Western nations.
What Causes Osteomalacia and Rickets?
- A chief cause of osteomalacia is intestinal malabsorption of vitamin D.
- Osteomalacia may be caused by disorders of any of the organs involved in vitamin D synthesis, such as the skin, kidney and liver.
- Dietary deficiency of vitamin D is common, especially in the elderly and exclusively breast-fed infants. Vitamin D is supplied in the diet mainly through vitamin D-fortified dairy products and cereals. However, many adults do not consume enough.
- Inadequate exposure to sunlight reduces the amount of vitamin D produced naturally by the skin.
- Chronic renal failure and complications of hemodialysis are potential causes.
- Chronic acidosis (an abnormal state of reduced alkalinity in the blood or body tissues, usually due to renal failure) may lead to osteomalacia.
- Osteomalacia may occur as a side effect of some anticonvulsant drugs used to treat epilepsy. They interfere with normal activation of vitamin D.
- Several rare hereditary disorders can cause low phosphorus blood levels (hypophosphatemia), resulting in osteomalacia. Hypophosphatemia may also result from chronic use of nonabsorbable antacids.
Symptoms of Osteomalacia and Rickets
- Bone pain in the arms, legs, spine and especially the hips
- Muscle weakness, waddling gait
- Unexplained bone fractures or deformities
- Painful spasms or cramps in the face, hands and feet due to low levels of calcium in the blood (rare)
- In rickets: bowed limbs (especially the legs), pot belly, waddling gait, disturbed growth
- Abnormal heart rhythms
- Numbness of arms and legs
- Numbness around the mouth
- Spasms of hands or feet
- Widespread bone pain, especially in the hips
- Skeletal and/or skull deformities
- Bow legs or knock knees
- Pigeon chest (forward protrusion of the chest bone)
- Impaired growth, resulting in short stature
- Dental deformities
- Delayed tooth formation
- Teeth defects
- Increased cavities
- Sleeping problems
- Poor muscle development and tone
- Delayed walking in children
Prevention of Osteomalacia and Rickets
Dietary intake of vitamin D-fortified foods (such as milk products) and adequate exposure to sunlight help prevent vitamin D deficiency.
Diagnosis of Osteomalacia and Rickets
- Patient history and physical examination
- X-rays to evaluate bone mass and fractures.
- Blood tests to measure vitamin D, calcium, phosphorus, parathyroid hormone levels and alkaline phosphatase and urine tests.
- Bone biopsy in some cases
How to Treat Osteomalacia and Rickets
- Oral supplements of vitamin D are given, sometimes in conjunction with calcium.
- For osteomalacia due to intestinal malabsorption, oral vitamin D or vitamin D injections may be needed. Calcium supplements may also be beneficial.
- Osteomalacia due to chronic renal failure requires correction of the acidosis.
- Disorders leading to low blood phosphorus are treated with large doses of oral phosphate supplements plus vitamin D metabolites.
- Skeletal deformities may be corrected surgically.
- Regular blood tests may be ordered to monitor blood levels of phosphorus and calcium in individuals with certain underlying medical conditions.
When to Call a Doctor
Consult a doctor if you or your child experiences bone pain, unexplained fractures or apparent limb deformities.
Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference
Simeon Margolis, M.D., Ph.D., Medical Editor
Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50
Updated by Remedy Health Media