Definition

Rickets (in children) and osteomalacia (in adults) are two forms of a metabolic bone disease resulting from vitamin D]]> deficiency. Both cause softening and weakening of bones because of defective or inadequate bone mineralization.

Rickets

© 2009 Nucleus Medical Art, Inc.

Causes

Rickets and osteomalacia result when there is a vitamin D deficiency in the body. This may occur when:

• The supply of vitamin D from the diet or sun exposure is inadequate.
• The metabolism of vitamin D is abnormal.
• Tissue is resistant to the action of vitamin D.

Vitamin D]]> regulates ]]>calcium]]> absorption in the body. It also controls levels of calcium and phosphate in bone. Vitamin D is absorbed in the intestines from food. Vitamin D is also produced by the skin during exposure to sunlight.

Most often, rickets and osteomalacia are caused by a deficiency of vitamin D. This can result from:

• Insufficient vitamin D in the diet. In children, this may be related to:
  • Insufficient consumption of vitamin D-fortified milk
  • Insufficient intake of vitamin D supplements to children being breastfed or to children who are ]]>lactose intolerant]]>
• Lack of exposure to sunlight.

Less often, rickets and osteomalacia can be caused by other disorders that affect vitamin D absorption, metabolism, or action in the body such as:

• Kidney problems:
  • A hereditary disorder of the kidney called vitamin D-resistant rickets
  • Renal tubular acidosis—a nonhereditary kidney disorder which causes bone calcium to dissolve
  • Chronic ]]>kidney failure]]>
  • Long-term kidney ]]>dialysis]]>
• Diseases of the small intestines with malabsorption
• Disorders of the liver or pancreas disease
• Cancer
• Certain drugs, such as:
  • Certain seizure medications, such as phenytoin or phenobarbital
  • Acetazolamide
  • Ammonium chloride
  • Disodium etidronate
  • Fluoride treatment
• Toxicity or poisoning from:
  • Cadmium
  • Lead
  • Aluminum
  • Outdated tetracycline

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. Risk factors for rickets/osteomalacia include:

• Age in children: 6 to 24 months old
  • Either the child is consuming breast milk (from a mother who is deficient in vitamin D) or milk not fortified with vitamin D.
• Age in adults: 50-80 years
• Lactose intolerance with inadequate intake of vitamin D-fortified milk
• Family history of rickets
• Race: Black, especially in association with breastfeeding

Symptoms

Symptoms may include:

• Bone pain and tenderness
• Skeletal and/or skull deformities
• Bow legs or knock knees
• Deformity or curvature of the spine
• Pigeon chest (forward protrusion of the chest bone)
• Impaired growth, resulting in short stature
• Susceptibility to bone fractures
• Dental deformities
• Delayed tooth formation
• Defects in teeth
• Increased cavities
• Loss of appetite or weight loss
• Difficulty sleeping
• Poor muscle development and tone
• Muscle weakness
• Delay of learning to walk in children

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. Tests to confirm the diagnosis may include:

• Blood and urine tests
• Bone x-rays]]>
• Bone ]]>biopsy]]> , when other tests are not conclusive

Treatment

Treatment attempts to:

• Correct the underlying cause
• Relieve or reverse symptoms

Prevention

To help prevent rickets or osteomalacia:

• Drink vitamin D-fortified milk.
• Consume sufficient vitamin D, calcium, and other minerals. If you think your diet may be deficient, talk with your doctor about alternate sources of vitamins and minerals.
• Get sufficient, but not excessive, exposure to sunlight. Fifteen minutes a day is usually considered sufficient. Any longer than that requires sun protection with clothing or sunscreens, especially in fair-skinned infants or children. Children with dark skin and their mothers are at increased risk for rickets and may need more sun exposure and dietary supplementation with vitamin D.
• Breastfed, dark-skinned babies should receive 400 International Units per day (IU/d) of supplementation with vitamin D starting at no later than two months of age.