Rickets

Rickets causes soft, weak bones in children.

Rickets causes soft, weak bones in children. It usually occurs when they do not get enough vitamin D, which helps growing bones absorb the minerals calcium and phosphorous. It can also happen when calcium or phosphorus levels are too low.

Your child might not get enough vitamin D if he or she

  • Has dark skin
  • Spends too little time outside
  • Has on sunscreen all the time when out of doors
  • Doesn't eat foods containing vitamin D because of lactose intolerance or a strict vegetarian diet
  • Is breastfed without receiving vitamin D supplements
  • Can't make or use vitamin D because of a medical disorder such as celiac disease

In addition to dietary rickets, children can get an inherited form of the disease. Symptoms include bone pain or tenderness, impaired growth, and deformities of the bones and teeth. Your child's doctor uses lab and imaging tests to make the diagnosis. Treatment is replacing the calcium, phosphorus, or vitamin D that are lacking in the diet. Rickets is rare in the United States.

You can prevent rickets by making sure that your child gets enough calcium, phosphorus, and vitamin D in the diet. People who have gastrointestinal or other disorders may need to take supplements. Ask your child's health care provider.

Kidney (renal) causes of poor vitamin D absorption should be treated right away. People who have renal disorders should have their calcium and phosphorus levels monitored regularly.

Genetic counseling may help people who have a family history of inherited disorders that can cause rickets.

Vitamin D helps the body control calcium and phosphate levels. If the blood levels of these minerals become too low, the body may produce hormones that cause calcium and phosphate to be released from the bones. This 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 production 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

You may not get enough vitamin D from your diet if you:

  • Are lactose intolerant (have trouble digesting milk products)
  • Do not drink milk products
  • Follow a vegetarian diet

Infants who are breastfed only may develop vitamin D deficiency. Human breast milk does not supply the proper amount of vitamin D. This can be a particular problem for darker-skinned children in winter months (when there are lower levels of sunlight).

Not getting enough calcium and phosphorous in your diet can also lead to rickets. Rickets caused by a lack of these minerals in diet is rare in developed countries, because calcium and phosphorous are found in milk and green vegetables.

Your genes may increase your risk of rickets. Hereditary rickets is a form of the disease that is passed down through families. It occurs when the kidneys are unable to hold onto the mineral phosphate. Rickets may also be caused by kidney disorders that involve renal tubular acidosis.

Disorders that reduce the digestion or absorption of fats will make it more difficult for vitamin D to be absorbed into the body.

Occasionally, rickets may occur in children who have disorders of the liver, or who cannot convert vitamin D to its active form.

Rickets is rare in the United States. It is most likely to occur in children during periods of rapid growth, when the body needs high levels of calcium and phosphate. Rickets may be seen in children ages 6 to 24 months. It is uncommon in newborns.

Symptoms of rickets include:

  • Bone pain or tenderness in the arms, legs, pelvis, and spine
  • Decreased muscle tone (loss of muscle strength) and weakness that gets worse
  • Dental deformities, including delayed tooth formation, defects in the tooth structure, holes in the enamel, and increased cavities (dental caries)
  • Impaired growth
  • Increased bone fractures
  • Muscle cramps
  • Short stature (adults less than 5 feet tall)
  • Skeletal deformities such as an odd-shaped skull, bowlegs, bumps in the ribcage (rachitic rosary), breastbone that is pushed forward (pigeon chest), pelvic deformities, and spine deformities (spine that curves abnormally, including scoliosis or kyphosis)

A physical exam reveals tenderness or pain in the bones, but not in the joints or muscles.

The following tests may help diagnose rickets:

  • Arterial blood gases
  • Blood tests (serum calcium)
  • Bone biopsy (rarely done)
  • Bone x-rays
  • Serum alkaline phosphatase
  • Serum phosphorus

Other tests and procedures include the following:

  • Alkaline phosphatase (ALP) isoenzyme
  • Calcium (ionized)
  • PTH
  • Urine calcium