This bone disorder is most commonly caused by a nutritional deficiency of vitamin D or an inherited inability to utilize vitamin D, which is essential for skeletal development. It also may be caused by very rare, inherited disorders of metabolism, certain types of liver and kidney disease, and diseases that interfere with the absorption of vitamin D. Since sunlight triggers the conversion of a substance in the skin to vitamin D, lack of sun exposure also can lead to vitamin D deficiency rickets. Premature infants, babies with dark skin, and breast-fed babies whose mothers are poorly nourished or unexposed to sunlight are a particular risk.

WHEN SHOULD I SUSPECT THAT MY CHILD HAS RICKETS?
Vitamin D deficiency rickets is most common in children between four months and two years of age. If other family members are affected, the inherited forms of the disease may be diagnosed in early infancy, since doctors will be alert to the possibility that it may develop. Otherwise, inherited rickets may not become apparent until the child starts to walk.

Symptoms of rickets include restlessness, irritability, trouble sleeping, pelvic pain, muscle weakness and slowed development, such as difficulty in learning to crawl or walk. An infant with rickets may have extremely thin skull bones that get indented with slight pressure and spring back to normal when pressur is removed. Babies over six months old with rickets may have flattened, square skulls, and their fontanels (the soft spots on the head) may remain open longer than normal.

Affected children are prone to frequent bouts of diarrhea, bone fractures or respiratory infections. Their teeth may come in late or have faulty enamel and decay early. The most noticeable sign of rickets, however, is bone deformity, which appears when the disease is advanced. Because the bones become soft, the legs may bow or turn inward. Curvature of the spine, enlargement of the ankles, knees or wrists, and bending of the ends of the ribs (which causes the chest to thrust out) are other possible manifestations.

WHAT CAUSES RICKETS?
As noted earlier, rickets results from deficiency or improper metabolism of vitamin D. If a child's diet is low in vitamin D—as may be the case with vegetarian diets that exclude milk—he may develop rickets.

IS MEDICAL ATTENTION NECESSARY?
Yes. The diagnosis requires a careful checkup, and treatment should be prescribed by a physician.

HOW CAN THE PEDIATRICIAN TELL IF MY CHILD HAS RICKETS?
Diagnosis of rickets usually requires X rays, even if the pediatrician can spot the characteristic bone deformities of an advanced case. Blood tests usually are required as well.

WHAT TREATMENTS ARE AVAILABLE?
Treatment primarily consists of giving the child vitamin D supplements in therapeutic amounts.

PREVENTING RICKETS
Rickets is rare in the United States because it is usually very easy to prevent. Virtually all cow's milk and all standard infant formulas are manufactured with added vitamin D. Vitamin D supplements are readily available for premature infants, vegetarians and others who may not take in enough nutrients naturally. It often is recommended that nursing mothers who are vegetarians and have dark skin take these supplements. Foods that are high in vitamin D include:

• Vitamin D-fortified milk, margarine and breakfast cereals

• Liver, some fish, cod liver oil, egg yolks and butter

• In addition, some exposure to sunlight will help the body produce vitamin D, although precautions must be taken to avoid the pitfalls of overexposure.

GETTING HELP
Call your doctor if your child develops:

• Bowing of the legs or spine or any other bone deformity

• Flattening of the top of the head

• Enlargement of the joints such as the ankles, knees or wrists

• Any fracture, especially one that seems to have occurred easily

• Noticeable delays in development combined with poor sleeping habits and general irritability

Excerpt from THE DISNEY ENCYCLOPEDIA OF BABY & CHILD CARE, © 1995 DSH Communications, Inc. This material is based on current medical research and, to the best of the editors' knowledge and understanding, is accurate and valid. However the reader should not use information contained in this material to alter a medically prescribed regimen or as a form of self-treatment, without seeking the advice of a licensed physician.