Definition

     Rickets is a softening of the bones in children potentially leading to fractures and deformity. Rickets is among the most frequent childhood diseases in many developing countries. The predominant cause is a vitamin D deficiency, but lack of adequate calcium in the diet may also lead to rickets. Although it can occur in adults, the majority of cases occur in children suffering from severe malnutrition, usually resulting from famine or starvation during the early stages of childhood. Osteomalacia is the term used to describe a similar condition occurring in adults, generally due to a deficiency of vitamin.

Causes

     Vitamin D acts as a hormone to regulate calcium and phosphorus levels in your bones. You absorb vitamin D from two sources:

• Sunlight. Your skin produces vitamin D when it's exposed to sunlight. This is the most common way for most adolescents and adults to produce the vitamin.

• Food. Your intestines absorb vitamin D from the foods you eat or from supplements or multivitamins you may take.

     In the past, dietary vitamin D deficiency was the most common cause of rickets in the United States. Now, with the increased use of vitamin supplements and the variety of foods fortified with vitamin D (such as orange juice and breakfast cereals), vitamin D deficiency cases of rickets have fallen.

     Currently in the United States, conditions that impair vitamin D absorption such as the surgical removal of all or part of the stomach (gastrectomy) and celiac disease, in which the small intestine doesn't absorb certain nutrients from food, cause most cases of rickets.

     Other causes of rickets include:

• Hereditary rickets (X-linked hypophosphatemia), an inherited form of rickets caused by the inability of the kidneys to retain phosphorus, or a complication of renal tubular acidosis, a condition in which your kidneys are unable to excrete acids into urine

• Lack of exposure to sunlight, which stimulates the body to make vitamin D

Risk factors

     Children 6 to 24 months old are most at risk of rickets because they're growing rapidly, and vitamin D, calcium and phosphorus play a major role in the growth process.

     Risk factors for rickets include:

• Lack of vitamin D. Breast-fed infants who don't receive supplemental vitamin D are at increased risk of developing rickets. While exposure to sunlight could produce the necessary amounts of vitamin D, sunburn and skin cancer are real dangers for young children. Sunscreens also markedly decrease vitamin D production.

• Lack of calcium and phosphorus. Children who don't get enough calcium and phosphorus in their diets are at increased risk of rickets. The availability of milk and other products that contain these minerals make this cause a rarity for rickets in the United States and other developed countries.

Symptoms

• Bone pain or tenderness

  • Arms

  • Legs

  • Spine

  • Pelvis

• Skeletal deformities

  • Bowlegs

  • Forward projection of the breastbone (pigeon chest)

  • Bumps in the rib cage (rachitic rosary)

  • Asymmetrical or odd-shaped skull

  • Spine deformities (spine curves abnormally, including scoliosis or kyphosis)

  • Pelvic deformities

• Increased tendency toward bone fractures

• Dental deformities

  • Delayed formation of teeth

  • Defects in the structure of teeth, holes in the enamel

  • Increased incidence of cavities in the teeth (dental caries)

  • Progressive weakness

  • Decreased muscle tone (loss of muscle strength)

• Muscle cramps

• Impaired growth

• Short stature (adults less than 5 feet tall)

Signs and Tests  

     A physical exam reveals tenderness or pain in the bones, rather than in the joints or muscles.

     The following tests may help diagnose rickets:

• Blood tests (serum calcium) may show low levels of calcium.

  • Tetany (prolonged muscle spasm) may occur if serum levels of calcium are low.

  • Chvostek's sign may be positive (a spasm of facial muscles occurs when the facial nerve is tapped) indicating low serum levels of calcium.

• Serum phosphorus may be low.

• Serum alkaline phosphatase may be high.

• Arterial blood gases may reveal metabolic acidosis.

• Bone x-rays may show loss of calcium from bones or changes in the shape or structure of the bones.

• A bone biopsy is rarely performed but will confirm rickets.

     Other tests and procedures include the following:

• PTH

• Urine calcium

• Calcium (ionized)

• ALP (alkaline phosphatase) isoenzyme

Screening and Diagnosis

     A doctor may diagnose rickets by:

• Blood tests to measure calcium and phosphorus levels

• X-rays of affected bones

Complications

• Chronic skeletal pain

• Skeletal deformities

• Skeletal fractures, may occur without cause

Prevention

     Although most adolescents and adults receive much of their necessary vitamin D from exposure to sunlight, infants and young children need to avoid direct sun entirely or be especially careful by always wearing sunscreen.

• Vitamin D supplements

     In light of these factors, and because human milk contains only a small amount of vitamin D, the American Academy of Pediatrics recommends that all breast-fed infants receive 200 international units (IU) of oral vitamin D daily beginning during the first two months of life and continuing until the daily consumption of vitamin D-fortified formula or milk is two to three glasses or 500 milliliters (mL).

     Vitamin D supplements for infants generally come in droplet form. Use only supplements that contain up to 400 IU of vitamin D per mL or tablet. Avoid supplements containing a higher concentration of vitamin D (some forms come in levels of up to 8,000 IU/mL), because they're unsafe for children.

• Getting enough calcium

     Calcium and phosphorus consumption are also important for bone formation in childhood. Breast milk is the best source of calcium during a child's first year of life. Most commercially available formulas also meet calcium requirements. Because of these factors, infants in the United States generally achieve 100 percent of their recommended intake of calcium. Unfortunately, this trend stops as children grow into adolescents and adults, and many fail to take in enough calcium, an essential component of skeletal formation. This lack of calcium may lead to osteomalacia, a form of rickets in adults.

     Recommended daily intake of calcium is as follows (serving sizes vary with age):

• 1 to 3 years of age. 500 milligrams (mg) (two servings of dairy products a day)

• 4 to 8 years of age. 800 mg (two to three servings of dairy products a day)

• 9 to 18 years of age. 1,300 mg (four servings of dairy products a day, as most bone mass production occurs during this period)

• 19 to 50 years of age. 1,000 mg a day (three servings of dairy products a day)

     Milk accounts for three-fourths of the calcium in the food supply of the United States. If you're not drinking milk, be sure to find another source. Remember that low-fat can still mean high-calcium. Other sources of calcium include leafy green vegetables (spinach), fortified orange juices, fortified breakfast cereals and calcium supplements.

Treatment

     The treatment goals include relieving the symptoms and correcting the underlying cause to prevent recurrence. If the condition is not corrected while children are still growing, skeletal deformities and short stature may be permanent, but if it is corrected while the child is young, skeletal deformities often reduce or disappear with time.

     The symptoms disappear with the replacement of deficient calcium, phosphorous, and/or vitamin D.

   Biologically active form of vitamin D could be used in people who have difficulty in converting vitamin D to its active form.

     Including fish, liver and processed milk, which are rich sources of vitamin D in the diet.

      Exposure to moderate amounts of sunlight.

      Skeletal deformities could be corrected by maintaining a good posture and bracing could help in reducing the deformities.

      Some skeletal deformities can be corrected only with surgical correction.