Rickets

Rickets is a common bone disease worldwide that is associated with disturbances in calcium and phosphate homeostasis and can lead to short stature and joint deformities. Rickets can be diagnosed based on history and physical examination, radiological features, and biochemical tests. It can be classified into 2 major groups based on phosphate or calcium levels: phosphopenic and calcipenic. Knowledge of categorization of the type of rickets is essential for prompt diagnosis and proper management. Nutritional rickets is a preventable disease through adequate intake of vitamin D through both dietary and sunlight exposure. There are other subtypes of rickets, such as vitamin D–dependent type 1 rickets and vitamin D–dependent type 2 rickets (due to defects in vitamin D metabolism), renal rickets (due to poor kidney function), and hypophosphatemic rickets (vitamin D–resistant rickets secondary to renal phosphate wasting wherein fibroblast growth factor-23 (FGF-23) often plays a major role), which requires closer monitoring and supplementation with activated vitamin D with or without phosphate supplements. An important development has been the introduction of burosumab, a human monoclonal antibody to FGF-23, which is approved for the treatment of X-linked hypophosphatemia among children 1 year and older.

Symptoms of rickets include:

pain or tenderness in the bones of the arms, legs, pelvis, or spine

stunted growth and short stature

bone fractures

muscle cramps

teeth deformities, such as:

delayed tooth formation

holes in the enamel

abscesses

defects in the tooth structure

an increased number of cavities

skeletal deformities, including:

an oddly shaped skull

bowlegs, or legs that bow out

bumps in the ribcage

a protruding breastbone

a curved spine

pelvic deformities

Call your doctor right away if your child is showing signs of rickets. If the disorder isn’t treated during a child’s growth period, the child may end up with a very short stature as an adult. Deformities can also become permanent if the disorder goes untreated.

Nutrition problems or genetics are usually the cause of rickets.

Nutritional rickets: This is usually caused by not taking in enough vitamin D, which your body uses to absorb calcium. Some of the causes of this deficiency include:

Insufficient exposure to sunlight (which helps your body make its own vitamin D).

Lack of vitamin D in your child’s diet. This can happen with vegetarian/vegan diets, lactose intolerance or conditions that limit how much vitamin D your child’s body can absorb (such as Crohn’s disease, celiac disease, cystic fibrosis or ulcerative colitis).

A diet very low in calcium.

Inherited rickets: Several genetic diseases interfere with how your child’s body absorbs vitamin D. Other genetic conditions affect how your body handles phosphorus and also cause rickets. These types of disorders are rare.

Risk factors for rickets include the following:

Age

Rickets is most common in children who are between 6 and 36 months old. During this time period, children usually experience rapid growth. This is when their bodies need the most calcium and phosphate to strengthen and develop their bones.

Diet

You have a higher risk of developing rickets if you eat a vegetarian diet that doesn’t include fish, eggs, or milk. You’re also at an increased risk if you have trouble digesting milk or have an allergy to milk sugar (lactose). Infants who are only fed breast milk can become deficient in vitamin D as well. Breast milk doesn’t contain enough vitamin D to prevent rickets.

Skin color

Children of African, Pacific Islander, and Middle Eastern descent are at the highest risk for rickets because they have dark skin. Dark skin doesn’t react as strongly to sunlight as lighter skin does, so it produces less vitamin D.

Geographic location

Our bodies produce more vitamin D when they’re exposed to sunshine, so you’re more at risk for rickets if you live in an area with little sunlight. You’re also at a higher risk if you work indoors during daylight hours.

Genes

One form of rickets can be inherited. This means that the disorder is passed down through your genes. This type of rickets, called hereditary rickets, prevents your kidneys from absorbing phosphate.

Left untreated, rickets can lead to:

Failure to grow

An abnormally curved spine

Bone deformities

Dental defects

Seizures

Exposure to sunlight provides the best source of vitamin D. During most seasons, 10 to 15 minutes of exposure to the sun near midday is enough. However, if you're dark-skinned, if it's winter or if you live in northern latitudes, you might not be able to get enough vitamin D from sun exposure.

In addition, because of skin cancer concerns, infants and young children, especially, are warned to avoid direct sun or to always wear sunscreen and protective clothing.

To prevent rickets, make sure your child eats foods that contain vitamin D naturally — fatty fish such as salmon and tuna, fish oil and egg yolks — or that have been fortified with vitamin D, such as:

Infant formula

Cereal

Bread

Milk, but not foods made from milk, such as some yogurts and cheese

Orange juice

Check labels to determine the vitamin D content of fortified foods.

If you're pregnant, ask your doctor about taking vitamin D supplements.