Rickets
Definition
Rickets is a disorder caused by a lack of vitamin D, calcium, or phosphate. It leads to softening and weakening of the bones.
Alternative Names
Osteomalacia in children; Vitamin D deficiency; Renal rickets; Hepatic rickets
Causes
Vitamin D helps the body control calcium and phosphate levels. If the blood levels of these minerals become too low, the body may produce hormones that cause calcium and phosphate to be released from the bones. This leads to weak and soft bones.
Vitamin D is absorbed from food or produced by the skin when exposed to sunlight. Lack of vitamin D production by the skin may occur in people who:
- Live in climates with little exposure to sunlight
- Must stay indoors
- Work indoors during the daylight hours
You may not get enough vitamin D from your diet if you:
- Are lactose intolerant (have trouble digesting milk products)
- DO NOT drink milk products
- Follow a vegetarian diet
Infants who are breastfed only may develop vitamin D deficiency. Human breast milk does not supply the proper amount of vitamin D. This can be a particular problem for darker-skinned children in winter months. This is because there are lower levels of sunlight during these months.
Not getting enough calcium and phosphorous in your diet can also lead to rickets. Rickets caused by a lack of these minerals in the diet is rare in developed countries. Calcium and phosphorous are found in milk and green vegetables.
Your genes may increase your risk for rickets. Hereditary rickets is a form of the disease that is passed down through families. It occurs when the kidneys are unable to hold onto the mineral phosphate. Rickets may also be caused by kidney disorders that involve renal tubular acidosis.
Disorders that reduce the digestion or absorption of fats will make it more difficult for vitamin D to be absorbed into the body.
Sometimes, rickets may occur in children who have disorders of the liver. These children cannot convert vitamin D to its active form.
Rickets is rare in the United States. It is most likely to occur in children during periods of rapid growth. This is the age when the body needs high levels of calcium and phosphate. Rickets may also be seen in children ages 6 to 24 months. It is uncommon in newborns.
Symptoms
Symptoms of rickets include:
- Bone pain or tenderness in the arms, legs, pelvis, and spine
- Decreased muscle tone (loss of muscle strength) and weakness that gets worse
- Dental deformities, including delayed tooth formation, defects in the tooth structure, holes in the enamel, and increased cavities (dental caries)
- Impaired growth
- Increased bone fractures
- Muscle cramps
- Short stature (adults less than 5 feet or 1.52 meters tall)
- Skeletal deformities such as an odd-shaped skull, bowlegs, bumps in the ribcage (rachitic rosary), breastbone that is pushed forward (pigeon chest), pelvic deformities, and spine deformities (spine that curves abnormally, including scoliosis or kyphosis)
Exams and Tests
A physical exam reveals tenderness or pain in the bones, but not in the joints or muscles.
The following tests may help diagnose rickets:
- Arterial blood gases
- Blood tests (serum calcium)
- Bone biopsy (rarely done)
- Bone x-rays
- Serum alkaline phosphatase (ALP)
- Serum phosphorus
Other tests and procedures include the following:
- ALP isoenzyme
- Calcium (ionized)
- Parathyroid hormone (PTH)
- Urine calcium
Treatment
The goals of treatment are to relieve symptoms and correct the cause of the condition. The cause must be treated to prevent the disease from returning.
Replacing calcium, phosphorus, or vitamin D that is lacking will eliminate most symptoms of rickets. Dietary sources of vitamin D include fish liver and processed milk.
Exposure to moderate amounts of sunlight is encouraged. If rickets is caused by a metabolic problem, a prescription for vitamin D supplements may be needed.
Positioning or bracing may be used to reduce or prevent deformities. Some skeletal deformities may require surgery to correct them.
Outlook (Prognosis)
The disorder may be corrected by replacing vitamin D and minerals. Laboratory values and x-rays usually improve after about 1 week. Some cases may require large doses of minerals and vitamin D.
If rickets is not corrected while the child is still growing, skeletal deformities and short stature may be permanent. If it is corrected while the child is young, skeletal deformities often improve or disappear with time.
Possible Complications
Possible complications are:
- Long-term (chronic) skeletal pain
- Skeletal deformities
- Skeletal fractures, may occur without cause
When to Contact a Medical Professional
Contact your child's health care provider if you notice symptoms of rickets.
Prevention
You can prevent rickets by making sure that your child gets enough calcium, phosphorus, and vitamin D in their diet. Children who have digestive or other disorders may need to take supplements prescribed by the child's provider.
Kidney (renal) diseases that may cause poor vitamin D absorption should be treated right away. If you have renal disorders, monitor calcium and phosphorus levels regularly.
Genetic counseling may help people who have a family history of inherited disorders that can cause rickets.
References
Bhan A, Rao AD, Bhadada SK, Rao SD. Rickets and osteomalacia. In Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 31.
Demay MB, Krane SM. Disorders of mineralization. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 71.
Greenbaum LA. Vitamin D deficiency (rickets) and excess. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 64.
Weinstein RS. Osteomalacia and rickets. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 231.
Reviewed By: Charles I. Schwartz, MD, FAAP, Clinical Assistant Professor of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, General Pediatrician at PennCare for Kids, Phoenixville, PA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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