What Is Rickets? What Causes Rickets?

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Main Category: Bones / Orthopedics
Also Included In: Pediatrics / Children's Health
Article Date: 23 Jan 2010 - 0:00 PDT

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Rickets is a childhood bone disorder in which bones soften and become prone to fractures and deformity. Although rare in industrialized nations, it is still fairly common in some developing countries. The main cause of rickets is a lack of vitamin D. Not having enough calcium in one's diet may also be a cause of rickets, as may vomiting and diarrhea. Some childhood kidney and liver diseases can cause rickets, as may a digestive disorder complication that affects calcium and phosphorous absorption.

Rickets affects mainly children, although the disorder may also affect adults (osteomalacia). In most cases, the child suffers from severe and long-term malnutrition, usually during early childhood.

The term rickets comes from the Old English word "wrickken", meaning to twist or bend. Rickets was common in the UK and USA during the 19^th century.

According to Medilexicon's medical dictionary:

Rickets is a disease attributable to vitamin D deficiency, and characterized by overproduction and deficient calcification of osteoid tissue, with associated skeletal deformities, disturbances in growth, hypocalcemia, and sometimes tetany; usually accompanied by irritability, listlessness, and generalized muscular weakness; fractures are frequent.

For proper absorption of calcium and phosphorous from the gut, we need vitamin D. If vitamin D levels in a child are low, he/she may have inadequate calcium and phosphorous bone levels.

Providing a child with extra vitamin D and some minerals usually resolves the rickets problem.

What are the signs and symptoms?

A symptom is something the patient feels and reports, while a sign is something other people, such as the doctor detect. For example, pain may be a symptom while a rash may be a sign.

Signs and symptoms of rickets may include:

• Baby is floppy
• Bone pain
• Bone tenderness
• Bones break easily
• Costochondral swelling - prominent knobs of the bone at the costochondral joints are prominent; large beads show up under the skin of the rib cage
• Harrizon's groove - a horizontal line is visible at the lower margin of the thorax, where the diaphragm attaches to the ribs.
• Low calcium blood levels (hypcalcemia)
• Older children may have knock knees (genu valgum)
• Soft skull (craniotabes)
• The child's physical growth (height, weight) may be affected
• There may be spinal, pelvic or cranial deformities
• Toddlers may have bowed legs (genu varum)
• Uncontrolled muscle spasms, which may affect the entire body (tetany)
• Widening wrists

What are the causes of rickets?

Lack of vitamin D - the main cause of rickets. Our bodies need vitamin D in order to absorb calcium from the intestines. Ultraviolet light (from sunlight) helps our skin cells convert vitamin D from an inactive into an active state. If we do not have enough vitamin D, calcium that we get from the food we eat is not absorbed properly, causing hypocalcemia (lower-than-normal blood calcium) to develop. Hypocalcemia results in deformities of bones and teeth, as well as neuromuscular problems.

The following foods are known to be rich on vitamin D: eggs, fish oils, margarine, some fortified milks and juices, some oily fishes, and some soymilk products that have vitamin D added.

Genetic defect - hypophosphatemic rickets is a rare genetic fault that undermines the way the kidneys process phosphates. Phosphate blood levels are too low, leading to weak and soft bones.

Some diseases - some renal (kidney), hepatic (liver) and intestinal diseases can interfere with the way the body absorbs and metabolizes minerals and vitamins, resulting in rickets.

What are the Risk factors for rickets?

A risk factor is something which increases the likelihood of developing a condition or disease. For example, obesity significantly raises the risk of developing diabetes type 2. Therefore, obesity is a risk factor for diabetes type 2.

Poverty - rickets is more likely to occur among children who are poor.

Sunlight - children who do not get enough sunlight are more dependent on excellent nutrition to make sure they are getting enough vitamin D.

Malnutrition - rickets is more common in areas of the world where severe droughts and starvation occur.

How is rickets diagnosed?

Blood tests - serum calcium may reveal inadequate levels of calcium and phosphorus. Serum alkaline phosphatase levels may be high.

Metabolic acidosis may be revealed by arterial blood gases.

X-rays - these may reveal calcium loss in bones, or alterations in the structure or shape of the bones.

Bone biopsy - this can confirm rickets (rarely used).

What are the complications of rickets?

If left untreated, a child with rickets is more prone to fractures of the bone. If the rickets is severe and prolonged there may be permanent bone deformities.

Severely low blood calcium levels can lead to cramps, seizures and breathing problems.

Heart muscle weakness - this complication is rare.

What is the treatment for rickets?

The patient's dietary intake of calcium, phosphates and vitamin D is increased. This may involve exposure to sunlight (ultraviolet B light), consuming fish oils, and voisterol.

If enough ultraviolet B light exposure is available and used, as well as consuming adequate amounts of dietary and phosphorus, rickets can usually be reversed and prevented. The WHO (World Health Organization) recommends 400 IUs (international units) of vitamin D a day for babies and children.

If the rickets is caused by bad diet the patient should be given daily calcium and vitamin D supplements, an annual vitamin D injection, as well as being encouraged to eat vitamin D rich foods.

Treating genetic rickets - the patient will be prescribed phosphorus medications and active vitamin D hormones.

Other medical conditions - if the rickets has an underlying medical cause, such as kidney disease, that disease needs to be treated and controlled.

How can rickets be prevented?

Estimating the exact vitamin D needs of each human is very difficult, because it is hard to measure how much of the vitamin is synthesized in the skin under the influence of ultraviolet rays (sunlight). In countries that are not near the tropics and sunlight intensity is lower, it is important to provide a supplementary intake of vitamin D to prevent rickets. This may involve enriching milk, baby foods and some other food products, the administration of a daily vitamin D supplement, and massive doses of vitamin D when it is impossible for socioeconomic reasons to provide a vitamin supplement.

In areas with a lot of sunlight, the best way to prevent rickets is to expose the infant/child to the sun. While exposure to sunlight is a good source of vitamin D, it is important not to overdo it - excess sunlight exposure can lead to sunburn and eventually skin cancer.

Written by Stephanie Brunner (B.A.)
Copyright: Medical News Today
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