I. What is vitamin D deficiency rickets?
Vitamin D deficiency causes abnormal calcium and phosphorus metabolism in the body, resulting in impaired bone growth and skeletal deformities in severe cases, which is called vitamin D deficiency rickets. Dai Yuliang, Department of Pediatrics, Tangshan People’s Hospital
Calcium content and distribution in the body
The total amount of calcium in the body of adults is 700 to 1400 grams, of which more than 99.7% exists in the form of bone salts in bones and teeth, and only a small amount exists in blood, tissue fluid and cells. The normal value of calcium in the blood is 9 to 11 mg%, and despite the small amount of calcium in the blood, the role it plays is very critical. If the blood calcium is lower than the normal value, the excitability of neuromuscular increases, which leads to convulsions and laryngeal spasms, which can be life-threatening in serious cases.
Third, the absorption and excretion of calcium
Calcium mainly comes from food, only a small part of calcium in food is absorbed by the intestine after ingestion, most of it is excreted with feces, and a small part of absorbed calcium is excreted by urine. The absorption of calcium in the intestine is influenced by the following factors.
1, the amount of calcium in food: the more calcium in food, i.e., the higher the concentration of calcium in the intestine, the more calcium is absorbed.
2, the ratio of calcium and phosphorus in food: when the ratio of calcium and phosphorus in food is about 1:2, it is most beneficial to the intestinal absorption of calcium and phosphorus.
3, vitamin D: vitamin D can promote the absorption of calcium in the small intestine, which is one of the reasons for using vitamin D to treat vitamin D deficiency rickets.
Fourth, the regulation of blood calcium and its concentration
The normal concentration of blood calcium is 9 to 11 mg%. Calcium absorbed from food in the small intestine first enters the blood, and then is deposited in the bones or enters the cells. However, under normal conditions, a small amount of calcium is also released from the bones into the blood. Therefore, blood calcium is actually in a dynamic balance to maintain normal physiological functions in the body.
When blood calcium decreases, more calcium is released from the bones into the blood and insufficient calcium is deposited in the bones, thus causing impaired bone growth and development.
V. Why do children get rickets?
Most of the rickets in children are caused by vitamin D deficiency. When vitamin D is deficient, the calcium absorbed by the intestine decreases, blood calcium decreases, bone calcium is then released into the blood, and the bones cannot be calcified, thus causing impaired bone growth and development. It can be seen that the root cause of rickets in children is due to vitamin D deficiency.
VI. Why does vitamin D deficiency occur in children
Under normal circumstances, there are two sources of vitamin D: one is food, and the other is self-synthesis. Vitamin D in food comes from plants (vitamin D2) or animals (vitamin D3); human skin also contains a predecessor substance of vitamin D3 called vitamin D3 prodigy, which is changed to vitamin D3 by ultraviolet radiation in sunlight, which is the main source of vitamin D in humans. Children, especially infants, do not get enough vitamin D from food because of the small variety of food they eat; they grow fast and require relatively more vitamin D. In addition, the younger they are, the less chance they have to be exposed to ultraviolet light outdoors, so their bodies do not synthesize enough vitamin D. Therefore, children are prone to vitamin D deficiency.
VII. What are the manifestations of rickets?
In the early stage, the main manifestations are unstable sleep, easy to wake up, crying at night, excessive sweating (not related to temperature), occipital baldness; later on, square skull, lower edge of the rib cage outward, chicken chest, and in severe cases, bending deformation of the legs. Teething, sitting, walking and talking are later than normal children.
Eight, how to prevent rickets
Pregnant women should pay attention to pregnancy health care and avoid premature birth. For premature babies, twins, artificially fed babies or newborns born in winter, vitamin D can be given orally from 1-2 weeks after birth, 500~1000 units per day and taken continuously. For those who cannot adhere to the oral dose, vitamin D 2.1~200,000 units or vitamin D 315,000~300,000 units can be given once by intramuscular injection. It can be maintained for 2~3 months. As long as the conditions and climate allow, try to have more outdoor activities and sunbathing (in the shade of trees in hot summer).
About calcium supplementation: Those who have sufficient milk may not need to take another calcium supplement. If the food does not contain enough calcium, or if the baby is premature or weak, calcium can be given at 1 gram per day.
IX. How to treat rickets
In the early stage, children often show anxious temper, sweating, less sleep, night crying, etc. At this time, you can take 5,000 to 10,000 units of vitamin D orally every day, and change it to preventive amount after one month. If you can’t take it orally, you can inject vitamin D 2.4 million units or vitamin D 3.3 million units intramuscularly, with 1 or 2 times, each time with an interval of 1 month.
At the extreme stage, children mostly have skeletal changes, so they can take 1000-20,000 units of vitamin D orally every day for 1 month and then change to preventive amount. If you cannot take it orally, you can inject vitamin D 2.4 million units or vitamin D 3.3 million units intramuscularly for 2 to 3 times with an interval of 1 month each time.
Application of calcium: In parallel with vitamin D treatment, take calcium gluconate orally 1 to 3 grams per day, or other calcium supplements can be used.
X. Prevention of vitamin D toxicity
Long-term high dose of vitamin D can be poisoned, manifested as loss of appetite, irritability, mental discomfort, low fever, pallor, nausea, vomiting, diarrhea or constipation, excessive drinking, polyuria, and in severe cases, calcification of multiple parts of the body, such as the heart, kidneys, joints, etc. Therefore, the prevention and treatment of rickets cannot be abused by vitamin D on its own and needs the guidance of a professional physician.