Rickets

• Skeletal deformities. These include bowed legs, abnormal curvature of the spine, pelvic deformities and breastbone projection in the chest.
• Fragile bones. Children with rickets are more prone to bone fractures.
• Impaired growth. Delayed growth in height or limbs may be a result of rickets.
• Dental problems. These include defects in tooth structure, increased chance of cavities, poor enamel and delayed formation of teeth.
• Bone pain. This includes dull, aching pain or tenderness in the spine, pelvis and legs.
• Muscle weakness. Decreased muscle tone may make movement uncomfortable.

Causes

Vitamin D acts as a hormone to regulate calcium and phosphorus levels in your bones. If you don't get enough vitamin D, your body won't absorb calcium and phosphorus properly. When your body senses the imbalance of calcium and phosphorus in your bloodstream, it reacts by taking calcium and phosphorus from your bones to raise blood levels to where they need to be. This softens or weakens the bone structure, which can result in skeletal deformities, such as bowlegs or improper curvature of the spine. Osteomalacia is the adult version of rickets.

You absorb vitamin D from two sources:

• Sunlight. Your skin produces vitamin D when it's exposed to sunlight.
• Food. Your intestines absorb vitamin D that's found naturally in the foods you eat, or added to it during processing, or from supplements or multivitamins you may take.

Rickets can also be caused by 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. Additionally, conditions that impair the absorption of any fat soluble vitamin, which includes A, D, E and K, increases the risk 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 3 to 36 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.

Other 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 because although vitamin D does cross from mother to baby in the breast milk, it's not enough to prevent a deficiency. While exposure to sunlight could produce the necessary amounts of vitamin D, sunburn and skin cancer are real dangers. Sunscreens, which are used to protect against these dangers, can decrease vitamin D production by blocking the sun's ultraviolet rays.
• Lack of calcium and phosphorus. Children who don't get enough calcium and phosphorus in their diets are at increased risk of rickets.

Complications

While easily treated once it's diagnosed, rickets has a severe list of complications if left untreated. Untreated vitamin D deficiency rickets may lead to:

• Delays in your child's motor skills development
• Failure to grow and develop normally
• Skeletal deformities
• Chronic growth problems that can result in short stature
• Seizures
• Dental defects

Diagnosis

Your doctor or your child's doctor may diagnose rickets by:

• Physical examination. Your doctor will check if the pain or tenderness is coming directly from the bones, instead of the joints and muscles surrounding them.
• Blood tests. These measure calcium and phosphorus levels to see if they're normal.
• X-rays. Your doctor may take images of affected bones to look for softening or weakness.
• Medical history. Kidney problems, celiac disease or diagnosis of a sibling with rickets may help lead your doctor to a rickets diagnosis.

References

http://www.medicinenet.com/rickets/article.htm

http://www.thelancet.com/journals/lancet/article/PIIS0140673603146363/abstract

http://bestpractice.bmj.com/best-practice/monograph/635.html

http://www.nhs.uk/Conditions/Rickets/Pages/Introduction.aspx