Rickets' is a vitamin deficiency disease of infancy and early childhood caused by lack of vitamin D. Rickets causes soft bones because enough vitamin D is not present to assist in calcium absorption. When enough calcium is not absorbed by
the bone, it does not harden properly, and is too soft to support the weight of the growing body properly.
Vitamin D is made by the body when it is exposed to ultraviolet light (sunlight). Vitamin D is also added to milk, milk products, and multi-vitamins pills. Some people who do not get enough sun exposure, milk products, or green vegetables may also develop the disease, but that rarely happens anymore. Vitamin D may be absorbed from food by the intestines or may be produced by the skin when the skin is exposed to sunlight. In its active form, vitamin D acts as a hormone to regulate calcium absorption from the intestine and to regulate levels of calcium and phosphate in the bones.
Sunlight is important to skin production of vitamin D, and environmental conditions where sunlight exposure is limited may reduce this source of vitamin D. Lack of vitamin D production by the skin may occur with indoor confinement or working indoors during the daylight hours, or in climates with little exposure to sunlight. Because vitamin D is a fat-soluble vitamin, conditions that reduce digestion or absorption of fats will decrease the ability of vitamin D to be absorbed from the intestines.
When the body is deficient in vitamin D, it is unable to properly regulate calcium and phosphate levels. If the blood levels of these minerals become too low, other body hormones may stimulate release of calcium and phosphate from the bones to the bloodstream to elevate the blood levels. Rickets is a bone disease that affects children when these deficiencies occur. It causes progressive softening and weakening of the bones' structure. There is a loss of calcium and phosphate from the bones, which eventually causes destruction of the supportive matrix. Rickets is fairly rare in the US. It is most likely to occur during periods of rapid growth, when the body demands high levels of calcium and phosphate. Rickets may be seen in young children 6 to 24 months old and is uncommon in newborns.
Nutritional causes of rickets occur because of a lack of vitamin D in the diet or in association with malabsorption disorders characterized by poor fat absorption. A dietary lack of vitamin D may occasionally occur in people on a vegetarian diet who do not drink milk products or in people who are lactose intolerant (have trouble digesting milk products). A dietary lack of calcium and phosphorous (rather than a lack of vitamin D) may also play a part in the nutritional causes of rickets. Rickets caused by a dietary lack of these minerals is rare in developed countries because calcium and phosphorous are present in milk and green vegetables.
Hereditary rickets is an inherited form of the disease caused when the kidneys are unable to retain phosphate. Rickets may also be caused by kidney disorders involving renal tubular acidosis.
Occasionally, it can also affect children who have disorders of the liver, do not adequately absorb fats and vitamin D, or cannot convert vitamin D to its active form. Renal osteodystrophy occurs in people with chronic renal failure. The manifestation is virtually identical to that of rickets in children and that of osteomalacia or osteoporosis in adults.
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. Rickets causes bone pain, slowed growth in children, dental problems, muscle loss and increased risk of fractures (easily broken bones).
The x-ray, or radiograph, in the article is the classic image of advanced rickets sufferers: bow legs (outward curve of long bone of the legs)and a deformed chest. Changes in the skull also occur causing a distinctive "square headed" appearance. These deformities persist into adult life.
Treatment involves increasing dietary intake of calcium, phosphate and vitamin D. Exposure to sunshine, cod liver oil, halibut-liver oil, and viosterol are all sources of vitamin D. A sufficient amount of sunlight each day and adequate supplies of calcium and phosphorus in the diet can prevent rickets. Darker skinned babies need to be exposed longer to the ultraviolet rays. The replacement of Vitamin D may correct rickets using these methods of ultraviolet light and medicine. Rickets can occur in adults, also. Then, it is caused by the inability of bone cells to calcify, or harden. Rickets occurs when the products of Vitamin D are scarce. Less frequently, nutritional shortage of calcium or phosphorus may produce rickets. Infants who are breastfeeding/breastfed and obtain no Vitamin D are at risk.