Rickets is a disease that is caused by a deficiency of vitamin D.
It is characterised by malformation of the bones and teeth and tends to occur in malnourished infants who are not exposed to the ultraviolet rays of the sun on a daily basis.
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Osteomalacia or adult rickets can occur in pregnant and breastfeeding women, the aged, people with coeliac or kidney disease or those who have undergone intestinal bypass surgery.
Treatment consists of improving the diet, providing vitamin D and calcium supplementation, and daily exposure to sunlight.
Alternative names
This disease is referred to as osteomalacia when it occurs in adults.
What is rickets?
Rickets is a vitamin D deficiency disease characterised by bone pain, muscle weakness and bone and tooth deformities.
What causes rickets?
Rickets in children, or osteomalacia in adults, is most frequently caused by a vitamin D deficiency. Such a deficiency can be caused by a lack of vitamin D in the diet, insufficient exposure to sunlight, or malabsorption of dietary vitamin D caused by other diseases and conditions that interfere with nutrient uptake, such as coeliac disease and intestinal bypass surgery. Excessive excretion of calcium in the urine due to illnesses such as inherited kidney disease (hypophosphataemia, Fanconi syndrome), kidney dysfunction or kidney tumours, can also cause rickets. The latter conditions are relatively rare and most cases of rickets are linked to dietary deficiency, lack of exposure to sunlight or coeliac disease.
Who gets rickets and who is at risk?
Rickets is more common in children, and in South Africa this condition tends to occur in infants and children who are either fed an inadequate diet or are kept indoors for long periods of time and not exposed to sunlight. The incidence is higher in the Western Cape during winter and in infants who are swaddled so comprehensively that they do not get a chance to synthesise vitamin D under the skin.
Pregnant and breastfeeding women who eat a diet deficient in vitamin D and calcium, and seldom expose their skin to sunlight, are at risk of developing adult rickets or osteomalacia.
Older people, especially those who are institutionalised and/or bedridden may be at risk of developing osteomalacia if their diets lack vitamin D, and/or they are not exposed to sunlight.
Patients suffering from coeliac disease or those who have undergone intestinal bypass surgery may be at risk if their condition interferes with the absorption of vitamin D from the digestive tract.
Rickets is no longer as prevalent as it was during the last century (in the early 1900s until after the First World War), when it reached epidemic proportions in malnourished populations living in areas with little sunshine.
Symptoms and signs of rickets
Rickets causes malformed bones and teeth. In babies the skull remains soft and the bones do not close properly. The bones of the skeleton are soft and the ends of the long bones of the legs and arms are enlarged. Characteristic symptoms of rickets include bow legs, a condition called “rachitic rosary” in which knobs of bone stick out of the chest, pigeon breast (protruding breast-bone) and a curved spine. The wrists, knees and ankle joints may be enlarged.
Rickets is also associated with weak, poorly developed muscles, lack of muscle tone, a protruding tummy, and a delay in walking. Infants are often restless and irritable.
Dental caries and misshapen teeth may be linked to rickets.
How is rickets diagnosed?
Your doctor will do a physical examination to determine if the bones of the skeleton are malformed and if any of the characteristic signs of rickets or osteomalacia are present. He or she will also test your muscles to detect weakness, and will probably take a blood sample for analysis and ask for X-rays of the skeleton to be done. In rare cases, a biopsy (tissue sample for laboratory analysis) of the bone tissue may be performed.
While taking a case history, the doctor will ask you about your diet and if you are getting enough sun exposure.
Can rickets be prevented?
Rickets caused by dietary deficiency can be prevented by eating a balanced diet that includes egg yolk, oily fish and milk products. Most margarines contain added vitamin D. Make sure that you and your children spend some time outdoors every day, so that the body gets a chance to manufacture vitamin D under the skin when it is exposed to ultraviolet rays.
Don’t wrap up babies so tightly that they never get a chance to produce vitamin D. Pregnant and breastfeeding women and older individuals should also spend time outdoors every day, particularly in winter.
Cod liver oil tablets are a rich source of vitamin D and your doctor may prescribe them if he/she suspects that you or your children are at risk of developing a vitamin D deficiency. Always take cod liver oil tablets as prescribed and do not increase the dose, as cod liver oil contains large quantities of vitamins A and D, which are stored in the human body. Excessive intake of cod liver oil can be harmful.
How is rickets treated?
If you have been clinically diagnosed with rickets, your doctor will advise you to increase your vitamin D and calcium intake by eating a healthy, balanced diet containing plenty of milk, cheese, dairy products, egg yolk and fish. Make sure that the margarine you are using contains vitamin D. Cod liver oil tablets may be prescribed to supplement vitamin D intake. Calcium supplements may also be prescribed if your diet appears to be deficient in calcium.
Also, spend about half an hour outside the house every day to expose your body to the ultraviolet rays of the sun. (However, remember to avoid the sun between
10 a.m. and 3 p.m. during the South Africa summer, especially if you are fair-skinned, because of the associated risk of skin cancer.)
What is the outcome of rickets?
If treated in time, the bone and tooth malformations in infants can to a great extent be reversed. In adults, exposure to sunlight and provision of adequate nutrition, including vitamin D and calcium supplements, should also reverse skeletal malformation. Dental damage may not respond to treatment and affected teeth may have to be extracted.
When to call the doctor
Consult your doctor if:
You suspect that your baby’s bones and teeth are malformed or not developing properly.
Your child has any of the symptoms listed above.
You suspect that your diet and/or the diet of your child does not contain sufficient vitamin D or calcium.
You and/or your children never go out of doors and you notice any bone or muscle changes.
You are bedridden, suffer from coeliac disease or have had intestinal bypass surgery.
References
Garrow, JS, James, WPT, Ralph, A (2000). Human Nutrition & Dietetics, 10th Edition. Churchill Livingstone, Edinburgh.
Proudfit, FT & Robinson, CH (1962). Normal and Therapeutic Nutrition, 12th Edition. MacMillan Co., New York.
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