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

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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.
  • Tissues are 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 breast fed 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 non-hereditary kidney disorder which causes bone calcium to dissolve
    • Chronic kidney failure
    • Long-tern 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    • Outdated tetracycline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: 6-24 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 breast feeding

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

Treating the Underlying Cause

Treatment of the underlying cause may include:

  • Adding the following to your diet:
    • Vitamin D-fortified dairy products
    • Foods high in vitamin D (such as fatty fish, egg yolk, and green vegetables)
    • Supplements of vitamin D, calcium, and other minerals
    • Biologically active vitamin D
  • Adequate but not excessive exposure to sunlight

Treating Symptoms

Treatment to relieve or correct symptoms may include:

  • Wearing braces to reduce or prevent bony deformities
  • In severe cases, surgery to correct bony deformities

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 – 15 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.
  • Breast fed dark-skinned babies should receive 400 International Units per day (IU/d) of supplementation with Vitamin D starting at no later than 2 months of age.