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 19th century.
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. A study published in JAMA in 2013 suggested that babies should be given a daily dose of vitamin D of 400 IU (international units) to help them stay healthy.
Providing a child with extra vitamin D and some minerals usually resolves the rickets problem.
Symptoms of rickets
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.
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.
Causes of rickets
Some of the conditions that can be caused by vitamin D deficiency.
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.
Risk factors for rickets
Vitamin D is described as the sunshine vitamin. A study published in the journal Pharmacology and Pharmacotherapeutics in 2012 suggested that 50% of the worldwide population may be deficient in vitamin D (source).
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.
Risk factors for rickets include:
- 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.
On the next page we look at the diagnosis of rickets, complications caused by the condition and the available treatments for rickets.