What is it about ?
Rickets is a disorder in the formation of bones in children, usually as a result of vitamin D deficiency. Vitamin D deficiency is caused by insufficient exposure to sunlight, insufficient intake of vitamin D, or insufficient absorption of vitamin D by the body.
Vitamin D and calcium are essential elements in the process of calcification of newly formed bones. This process leads to the ‘hardening’ of the bones. If it is disturbed, children will have a more fragile bone structure with bone deformities and abnormalities (conjugation cartilages and bone ends at the joints). This phenomenon usually goes hand in hand with tooth formation disorders.
In rare cases, a disorder in the metabolism of vitamin D, certain drugs (against fungi, for example) or a phosphate deficiency are the cause of this bone disease.
The adult form of rickets is called osteomalacia.
Groups that are at greater risk of vitamin D deficiency and ultimately rickets are:
- children up to 6 years of age who are not receiving vitamin D supplements;
- children who have a milk allergy ;
- children and adolescents who do not move enough;
- children who have dark skin (and therefore have a greater need for vitamin D) and who live in countries with less sunshine.
What is its frequency?
There are no precise figures regarding the frequency of rickets in Belgium. Although cases have become rare in our regions since the 1950s, the disease seems to have resurfaced since the turn of the century.
How to recognize it?
Children with rickets can be recognized by the following characteristics:
- skeletal abnormalities, such as strongly arched legs and prominent bumps in front of the ribs (“strings”);
- increased susceptibility to fractures;
- growth retardation ;
- weakness of muscles;
- retarded psychomotor development;
- increased susceptibility to infections;
- onset of seizures (due to hypocalcaemia, i.e. a lack of calcium in the blood).
If left untreated, rickets leads to worsening deformities of the limbs and pelvis. In addition, the formation of teeth is often disturbed.
In addition, children with rickets often suffer from pain in their bones, which, combined with weak muscles and the increased risk of fractures, limits their mobility.
How is the diagnosis made?
The doctor will first examine the development of the child’s growth, possible risk factors, eating habits, country of origin, style of dress, vitamin D supplementation.
He will then ask for a blood test to know the levels of calcium (normal or reduced in case of rickets), phosphate (often reduced in case of rickets), vitamin D and parathyroid hormone. This is because a chronic vitamin D deficiency can cause the parathyroid to produce too much parathyroid hormone. Urinalysis will also be performed.
The clinical examination will mainly focus on possible limb deformities, muscle pain, mobility of the arms, legs, hips, knees, etc.
The diagnosis of rickets is made on the basis of the results of all these examinations, but also on the basis of characteristic radiological manifestations, in particular in the thighs, lower legs and ribs (“string”).
Finally, the doctor will rule out other diseases that could explain the abnormal blood values, such as kidney failure, malabsorption (such as celiac disease) and liver disease.
What can you do ?
Make sure your child is not vitamin D deficient. Although sun exposure is not without risk and proper sun protection should be used, (protected) sun exposure is still necessary for healthy bone development. However, we cannot give any recommendations regarding the duration of sun exposure in infants and children, as each individual’s vitamin D production depends on different factors. ONE recommends spending a quarter of an hour a day outdoors, keeping at least hands and face uncovered.
Whether all pregnant women should always take vitamin D supplements is debated. On the other hand, your child must necessarily receive a vitamin D supplement from birth until the age of 6 years (400 units per day or 600 units per day if he has dark skin).
What can your doctor do?
In case of vitamin D deficiency, the doctor will prescribe a vitamin D supplement. The dose is 2000 units per day, in addition to the recommended daily allowance of vitamin D for age.
Your doctor will further advise you to ensure an adequate intake of calcium (usually at least 0.5 liters of dairy products per day) or will prescribe a calcium supplement.
In the event of rickets, the doctor will assess the effectiveness of the treatment through follow-up consultations. This follow-up involves a blood test and an x-ray of the wrists (after 3 to 6 months of treatment). Ineffective treatment, a doubtful diagnosis or a low calcium level accompanied by alarming symptoms such as seizures justify carrying out additional examinations with a specialist.
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