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Rickets

What is rickets and what causes it?

Rickets is a condition that affects growing bones – so it only occurs in children. (In this information leaflet, ‘children’ includes babies and teenagers.) Bones are made strong by a mineral which contains calcium. When a child has rickets, there is not enough mineral in the bones. This makes the bones softer and weaker than normal, and also causes weak muscles.

The main cause of rickets is lack of vitamin D. It is vitamin D which regulates the bone-building process and the way the body handles calcium.

Osteomalacia is the equivalent condition in adults. (See separate article called ‘Osteomalacia’ for more information.)

Lack of vitamin D (vitamin D deficiency), is caused by problems with our diet and lifestyle. (See separate article called ‘Vitamin D deficiency’ for more information.)

Most of our vitamin D is made in the body by the action of sunlight on the skin. This means that people who stay inside or who cover up their skin, struggle to make enough vitamin D. People can lack vitamin D if they spend too much time indoors, or cover up when outside. The problem is worse in cold climates, and for people with black or Asian skin types, where the effect of the sun on the skin is less. Some vitamin D is obtained from certain foods such as oily fish (for example, sardines, herring, tuna, salmon, and mackerel), and egg yolk. A diet low in these foods (for example, a vegetarian or vegan diet) will also contribute to a lack of vitamin D. However, most vitamin D deficiencies are due to lack of sunlight on the skin.

Babies get vitamin D from their mothers while in the womb, and then from milk until they are weaned. If a pregnant or breast-feeding woman is lacking in vitamin D, the baby will also have low vitamin D levels. This is a common reason why babies get rickets, and the problem can occur both in the newborn period and later.

Formula milk has added vitamin D to fortify it but breast and cow’s milk (in the UK) are low in vitamin D. Remember that breast-feeding has many advantages. A concern about vitamin D deficiency should not be a reason to stop breast-feeding (your baby can simply and easily be given vitamin supplement drops).

Another possible cause of rickets is a very severe lack of calcium in the diet. This is unlikely in western countries, but can occur with very restricted diets and in developing countries.

Rickets can be caused by other medical conditions which affect the way the body processes vitamin D or calcium. Some examples are:

  • Problems affecting the gut, such as coeliac disease, Crohn’s disease or malabsorption.
  • Some types of liver or kidney disease (because the liver and kidneys are involved in processing vitamin D).
  • Medicines which interfere with vitamin D: carbamazepine, phenytoin, primidone and barbiturates.
  • A few rare conditions, including some inherited ones, which affect the way the body uses vitamin D and calcium.

How common is rickets?

We don’t know how common rickets is, but it does affect many children in the UK. Some recent research suggests that rickets affects something like 1 in 1,000 children, and is much more likely in children of South Asian or Afro-Caribbean origin. Other research gives higher figures for rickets. In large cities in the UK, perhaps 20 children each year, with a diagnosis of rickets, would attend a hospital clinic.

Vitamin D deficiency, which makes children vulnerable to rickets, is very common. It probably affects around half of the children in the UK.

Who gets rickets?

Children who lack vitamin D for long periods may get rickets. Vitamin D deficiency is more likely to occur in the following situations:

  • Breast-fed babies whose mothers lack vitamin D, or breast-fed babies where weaning is delayed – if they are not taking vitamin drops.
  • Children who get very little sun on their skin, such as those who stay indoors a lot, or who cover up when outside. This could include children who are hospitalised long-term. Also, those who are protected from the harmful effects of the sun’s rays with high-factor sunscreen. It is important never to let your child get sunburn, as this is a risk factor for the later development of skin cancer.
  • Children with medical conditions which affect the way the body handles vitamin D, as listed above under the heading ‘What is rickets and what causes it?’.
  • Children with dark or black skins or of South Asian origin.
  • Children with a family history of vitamin D deficiency.

What are the symptoms of rickets?

With a lack of vitamin D, many children have no symptoms at first, or only vague ones such as tiredness or aches.

As the lack of vitamin D becomes more severe, other symptoms that may develop include:

  • Bone pains, often in the legs.
  • Muscle pains or muscle weakness.
  • Soft skull or leg bones. This can make the legs look curved or bow-legged.
  • Poor growth, or teeth which are delayed or weak.
  • When rickets if very severe, it can cause low levels of calcium in the blood. This can lead to muscle spasms (cramps), seizures and breathing difficulties. These need urgent hospital treatment.

How is rickets diagnosed?

It may be suspected from the child’s medical history, symptoms, or lifestyle. Blood can be tested for vitamin D and calcium levels. Also, blood tests for liver function may show changes linked to rickets. A bone X-ray (usually of the wrist bones) is often done. This can show changes due to rickets (and needs only a very small amount of X-rays).

Usually, blood tests plus a bone X-ray are enough to make the diagnosis. Extra tests may be needed if the reason why the child has rickets is in doubt, or if the child could have another medical condition which may be contributing to the rickets.

How is rickets treated?

Treatment is to take vitamin D supplements. This is generally taken as a form of vitamin D called ergocalciferol or calciferol. (There are other types of vitamin D which are used in certain cases.) The vitamin D is given in high doses, in order to improve the rickets quickly.

Vitamin D can be taken as liquids, tablets or injections. The liquids/tablets can be taken on a daily, weekly or monthly basis, depending on the dose needed and on which option is preferred. If injections are used, they are NOT needed very often. For example, the first two doses could be given a month apart, followed by a repeat injection every six months.

If lack of calcium is part of the problem, calcium supplements can also be taken. These can be liquids or tablets. If calcium levels are severely low and causing problems, calcium can be given by an infusion (a ‘drip’) in hospital.

Are there any side-effects of treatment?

It is very unusual to get side-effects from vitamin D or calcium if taken in the correct dose.

Doses of vitamin D or calcium which are too high can raise calcium levels in the blood. This would cause symptoms such as thirst, passing a lot of urine, reduced appetite, nausea or vomiting, dizziness, and headaches. If your child has these symptoms, see a doctor promptly so that your child’s calcium level can be checked by a blood test.

Some guidelines advise that children taking high vitamin D doses should have their calcium levels checked regularly during the first few weeks of treatment. In practice, this is not usually done unless there are symptoms of high calcium as described above.

Are there any complications of rickets?

Rickets causes softening of the bones, which can be cured by treatment. However, until treated, the bones are more prone to fractures. Severe and prolonged rickets, if treated very late, can cause permanent bone deformities such as bow-legs.

Rickets occasionally causes low levels of calcium in the blood. If severe, low calcium can lead to muscle spasms (cramps), seizures or breathing difficulties. These problems can be treated but need hospital admission. Very rarely, severe rickets has been reported to cause heart muscle weakness, which is cured by vitamin D treatment.

What is the prognosis (outlook)?

If treated promptly, the prognosis is very good. Most cases of rickets can be cured with vitamin D treatment. If rickets is untreated for a long time, there is a possibility that permanent deformities could result. If these cause problems with pain or perhaps walking, your child may need surgery to try to correct the deformity.

With prolonged or untreated rickets, the risk of getting osteoporosis (bone thinning and fractures in old age) may be increased. It is also possible that the risk of getting other diseases might be increased. This is because vitamin D is thought to help in preventing some conditions such as diabetes, heart disease and cancer.

How can rickets be prevented?

Babies and children

All breast-fed babies should be given vitamin drops such as AbidecĀ®, DalivitĀ® or Healthy Start Children’s Vitamin Drops. Babies fed by formula baby milk do not need vitamin drops, as this milk already contains vitamin D. Once weaned, all children should be given vitamin drops that contain vitamin D, until the age of five. Your GP can either prescribe vitamin drops, or you can buy them over-the-counter (OTC) in a pharmacy, or your health visitor can put you in touch with the Healthy Start scheme where you can get free vitamins and where you may also qualify for food vouchers (see below for details).

Pregnant and breast-feeding women

All pregnant or breast-feeding women should take vitamin D supplements, both for your own health and to help prevent rickets in your baby. Your doctor or midwife will advise on the dose. Pregnant women can get free prescriptions and vitamins.

Note: if you are pregnant, you should not take supplements containing large amounts of vitamin A (due to risk of harm to the unborn baby). Supplements labelled as suitable for pregnancy are safe to use.

Lifestyle changes to prevent rickets

Vitamin D deficiency can also be prevented by lifestyle changes (to get more sunshine and improve the diet). However, many people find it hard to change their children’s lifestyle, in which case supplements are advised.

Foods containing good amounts of vitamin D are: liver, some fish (mainly oily fish such as herring, sardines, pilchards, trout, salmon, tuna and mackerel), egg yolk, and fortified foods (which have vitamin D added) such as margarine and some breakfast cereals.

Exposure to sunlight helps to increase your vitamin D levels. (See separate article called ‘Vitamin D deficiency’ for more information.) However, it is vital not to allow your child to become sunburnt.

Calcium deficiency can be prevented by eating a reasonable amount of dairy food (milk, cheese and yoghurt). If the child has special dietary needs and does not, or cannot, eat dairy products, a dietician is usually asked to advise. Strict vegan diets can cause problems with calcium and vitamin D deficiencies.

Some special circumstances

Children with certain medical conditions which make them prone to vitamin D deficiency will need extra vitamin D. The dose needed will depend on which medical condition it is. See above for a list of these conditions, and discuss vitamin D with your doctor.

If you have been treated for rickets

Once rickets has been diagnosed and treated, prevention will be needed so that rickets does not recur in the future. Most children diagnosed with rickets need to take vitamin D supplements long-term. These can be either vitamin drops/tablets taken daily, or stronger vitamin D medicines or injections taken at longer intervals such as monthly or six-monthly.

If your child has had rickets, it would be sensible to discuss prevention with your doctor.

As a parent, if your child has rickets, it is likely that his or her brothers and sisters are also affected, and you too may be vitamin D-deficient. It is worth taking vitamin D supplements and arranging for any other children to be tested.

A useful source of information

Healthy Start scheme

Web: www.healthystart.nhs.uk
A government-run scheme where you can get free vouchers every week, which you swap for milk, fresh fruit, fresh vegetables and infant formula milk. You can also get free vitamins. You could qualify if you receive benefits (Jobseeker’s Allowance, Income Support or receive Child Tax Credit) or if you are pregnant and aged under 18.

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References

  • Pearce SH, Cheetham TD; Diagnosis and management of vitamin D deficiency. BMJ. 2010 Jan 11;340:b5664. doi: 10.1136/bmj.b5664.
  • Drug and Therapeutics Bulletin; Primary vitamin D deficiency in children. February 2006 44: 12-16; (Requires a subscription)
  • Pettifor JM; Nutritional rickets: deficiency of vitamin D, calcium, or both? Am J Clin Nutr. 2004 Dec;80(6 Suppl):1725S-9S. [abstract]
  • Holick MF; Vitamin D deficiency. N Engl J Med. 2007 Jul 19;357(3):266-81.
  • Update on Vitamin D, Scientific Advisory Committee on Nutrition, February 2007

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