Rickets is a disorder that affects children, causing poor development of the bones in the skeleton. The term rickets comes from the old English word ‘wrickken’, meaning to twist or bend. Rickets was common during Victorian times but nowadays, the condition is rare. Rickets in adults is known as osteomalacia (soft bones).
Bones are made up of four major parts:
- Matrix – collagen fibres that criss-cross,
- Minerals – calcium and phosphorous,
- Osteoclasts – bone-removing cells, and
- Osteoblasts – bone-producing cells.
Bone is a living tissue and microscopic (very small) areas of bone are naturally removed and replaced throughout your life. The different parts of the bone contribute to how soft or hard the bones are. The strength of new bone depends on the amount of mineral covering the matrix. The more mineral there is, the stronger the bone, and the less mineral there is, the weaker the bone.
The body needs enough calcium, phosphorous and vitamin D for bone mineralisation to take place. Vitamin D helps calcium get absorbed from the intestine and ‘pushes’ the calcium into the bone. It also helps the muscles work properly.
Rickets is characterised by deformed bones due to poor bone mineralisation. In many cases, the condition is caused by a vitamin D deficiency.
There is a form of genetic rickets called X-Linked Hypophosphatemia. This condition is characterised by the symptoms of rickets and by low phosphorus (a substance found in bone) in the blood, associated with high phosphate levels passed in the urine. It affects approximately 1 in 20,000 people and is more common in girls more than in boys.
Rickets occasionally develops in children with rare forms of kidney and liver disease. It can also occur as a complication of a digestive disorder that causes malabsorption (nutrients not being absorbed properly) of calcium or phosphorus.
The symptoms and features of rickets may include:
- soft skull bones (craniotabes),
- delayed closing of the anterior fontanelle (soft spot on a baby’s head),
- a prominent, square-shaped forehead,
- thickening of the knees (also known as knock-knees),
- thickening of the ankles and wrists,
- body weight causing arm and leg bones to bow,
- Harrison’s sulcus (indentation on the chest),
- poor growth and development,
- floppiness due to muscle disease or weakness,
- teeth taking longer to come through, and
- weak tooth enamel.
Another characteristic of rickets is known as Rachitic rosary. This is when your ribs push out through your chest and look similar to a set of beads. It can cause your sternum (breastbone) to become more prominent, leading to what is often described as a ‘pigeon chest’.
If your child has rickets, there is a chance that they may become anaemic (when the blood is unable to carry enough oxygen around the body). However, anaemia can usually be easily treated by replacing the iron that is missing in the body with iron tablets.
As your child gets older, symptoms of rickets may also include:
- waddling when walking,
- bone pain,
- bending and cracking bones, and
- muscle weakness and pain.
The four symptoms listed above also apply to adults who have ostemalacia (soft bones).
Bone pain will tend to mostly affect your legs, groin, thighs, back, knees and feet. As the condition profresses, the pain can spread to most of your body, making it hard to move around.
In rickets, a lower than normal amount of calcium and phosphate are deposited in your bones, which may weaken and become softer. The result may be bowing of your legs, curvature of your spine, and an increased risk that your bones will fracture or break easily.
Vitamin D deficiency
Vitamin D is a fat-soluble vitamin which means that it is stored by your body when it is not needed. The vitamin helps normal development of bones, teeth, and nerves, plus it keeps your heart healthy. Vitamin D also helps calcium to be absorbed from the intestine. We get most of our vitamin D from sunlight.
A deficiency of vitamin D over a long period of time causes rickets in children and ostomalacia (soft bones) in adults.
Provitamin D (provitamins are substances that the body can convert into vitamins) in your diet is converted to vitamin D by the action of sunlight on your skin. Children with a poor diet are more likely to be affected by rickets, particularly if they are also deprived of sunlight. Rickets is now rare in developed countries.
X-Linked Hypophosphatemia (genetic rickets) may be inherited. As a mother, you can pass the defective gene on to both your sons and daughters. As a father, you can pass the defective gene on to your daughters, but you cannot pass it on to your sons. However, in some cases of rickets, there is no one in the family with the condition.
Osteomalacia (soft bones) may affect you if:
- You have a diet that is deficient in vitamin D which is found in oily fish, eggs and dairy products, but not in plant foods. If you are a vegetarian or vegan, you can get vitamin D from vegetable margarines, some soya milks and, if necessary, by taking vitamin D supplements.
- You are not regularly exposed to sunlight. Sunlight promotes the production of vitamin D which, provided that you spend time outdoors, usually provides your body with an adequate supply. Most people have enough vitamin D stored in their body to last for two to three years.
- You have a calcium deficiency. Calcium is usually obtained by including foods such as milk and dairy products in your diet. Vegetarians and vegans can obtain calcium by eating leafy green vegetables, tofu, dried fruit, seeds, nuts, and foods that are fortified with the vitamin, such as certain breads.
Your chances of developing osteomalacia (soft bones) are also increased if:
- you have a bowel disease,
- you have Crohn’s disease (inflammation of the gastrointestinal tract),
- you have Coeliac disease (inflammatory condition caused by sensitivity to the protein gluten),
- you have a kidney disease, or
- you are taking certain medications, such as anti-epileptic drugs.