Rickets is a bone disease in children that causes weak bones, bowed legs, and other bone deformities. Children with rickets do not get enough calcium, phosphorus, or Vitamin D -- all of which are important for healthy growing bones.
Although considered a disease of the past, rickets has not been eliminated in the world, and it seems to be getting more common in the United States.
In some children, rickets is an inherited disease. Hereditary rickets requires very specialized medical care. This article does not provide detailed information about hereditary rickets, but focuses on nutritional rickets caused by Vitamin D and calcium deficiency.
Because breast milk contains very little Vitamin D, rickets is seen most commonly in babies who are exclusively breast fed for a long time.
Other factors that contribute to rickets include:
- Low calcium. Children with rickets usually take in less than 300 mg of calcium per day (about one cup of milk). Growing children need from 400 mg (babies) to 1500 mg (teens in the adolescent growth spurt) of calcium daily for good bone health.
- Lack of sun exposure. Our bodies make Vitamin D in our skin when it is exposed to good sunlight. Not enough sun means not enough Vitamin D.
- Darker skin. People with darker skin require more sun to make Vitamin D.
- Poor diet. Children adopted from abroad or other children experiencing extreme poverty sometimes have rickets due to a poor diet history. Lack of variety in the diet, such as eating lots of unleavened bread or a strictly vegetarian diet, can contribute to rickets, as can intake of too much fluoride.
- Lactose intolerance. Children who are lactose intolerant or on diets that restrict dairy intake are at higher risk for rickets.
A child with rickets may have the following symptoms:
- Weak muscle tone
- Delayed development, decreased growth, or "failure to thrive"
- Bowed legs and widening of the wrist and ankle bones
- Stooped posture
- Chest and rib deformities - Some children develop nodules (bumps) at the end of their ribs (known as "rachitic rosary"). Chest deformities can develop from deformities of the ribs, and lead to lung infections.
Your doctor will examine your child, looking for the signs and symptoms of rickets discussed above. In addition to a physical examination, your doctor may recommend specific tests to help determine whether your child has rickets.
X-rays create clear images of bones. X-rays of children with rickets may show fractures (broken bones) or breaks that are healing or have healed. They may also show decreased bone density, as well as bowing or other deformities of the arms or legs, and problems around the growth plates.
The level of calcium in our blood must stay constant. If we do not take in enough calcium, then our bodies will pull the calcium it needs out of our bones. This makes bones weak and fragile.
Your doctor can test the calcium, phosphorus, and Vitamin D levels in your child's blood. Normal blood calcium and phosphorus do not rule out rickets. Low blood calcium and phosphorus levels can indicate very serious rickets or the type of rickets that runs in families.
Your doctor may also test your child's blood to determine the levels of specific hormones that control bone activity.
Supplementation with adequate Vitamin D and calcium immediately begins the healing process.
Vitamin D supplementation of 1000-2000 international units (IU) per day is started at once. Sometimes much higher levels of Vitamin D are used under a doctor's care. Calcium intake should be 1000-1500 mg/day, whether by calcium-rich food or by supplementation.
Children with inherited rickets are usually treated by an expert in hormones (endocrinologist).
Although recovery may take many months, outcomes for children treated for rickets are good. Deformities of the bones from rickets, even severe bowed legs, can get better over time without surgery.
In advanced cases, surgery may be necessary to correct severely bowed or knock-kneed legs, and other bone deformities.
Other problems, such as chest or pelvic deformities and growth retardation, may be permanent. (For example, before rickets prevention was understood, pelvic deformities from rickets made natural childbirth difficult or impossible. Cesarean section surgery was developed in part to help women with permanent pelvic deformities from childhood rickets.)
The key to preventing rickets is to make sure your child is getting enough Vitamin D and calcium.
General recommendations include:
- Infants who are exclusively breast fed should be supplemented with 400 IU of Vitamin D every day (this amount is found in infant vitamin preparations). Nursing mothers should take 4000 IU of Vitamin D to increase Vitamin D in the breast milk.
- Older children and adolescents should get 1000-1500 IU of Vitamin D every day.
- Infants need about 400 mg of calcium daily (about 1 1/2 cups of milk). A rapidly growing teen might need 1500-2000 mg of calcium to form strong bones.
Unlike Vitamin D, calcium is in many foods, and a diet containing dairy and other calcium-rich foods can provide adequate daily calcium. Lactose intolerant or children who do not take dairy can be supplemented with calcium in liquid, gummy, chewable, or pill form. Supplemental calcium should not be taken all at once because our body cannot absorb more than about 500 mg at one time. Excessive amounts of supplemental calcium (more than about 2000 mg) are not helpful and can cause constipation and other problems.
Rickets remains a serious nutritional disorder that results from calcium or Vitamin D deficiency. Prevention of rickets is important. Playing outside in the sun and eating dairy products and other calcium-rich foods is the key to preventing rickets. Vitamin D should be supplemented for most children.
Rickets is treated with calcium and Vitamin D and has a good outlook after treatment.
Reviewed by members of the Pediatric Orthopaedic Society of North America
The American Academy of Orthopaedic Surgeons
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Rosemont, IL 60018