Understanding Rickets

Rickets

Rickets is a childhood condition where bones lack certain minerals. Although they all look the same on X-rays, there are several different types of rickets. The type depends on which mineral is deficient – either calcium, phosphorus, or the enzyme that helps create the mineral portion of bone, alkaline phosphatase.

Bone is made up of two substances: the organic collagen portion and the inorganic mineral portion. The inorganic portion of bone is made up of both calcium and phosphate. Rickets describes the softening and weakening of children’s bones. While rickets looks the same on X-rays, there are many different types. These types depend on which mineral is deficient (low) – either calcium, phosphorus, or the enzyme that helps create the mineral portion of bone. 

Calcium deficiency

The most common cause of calcium deficiency in bone is a lack of vitamin D, not a lack of calcium in the diet. This is because vitamin D allows the body to absorb calcium. If the body does not have enough calcium in the blood, then it will take the calcium out of bone instead. If this cycle continues, bones can become weaker. This can lead to a child developing physical signs of rickets, such as bowed legs or other bone deformities.

Phosphorus deficiency

Phosphates support the growth and repair of bones and teeth. The most common reason for a phosphorus deficiency in bone is an inherited disorder known as X-linked hypophosphatemic rickets. This disorder is caused by a defect in the PHEX gene, which regulates the movement of phosphate compounds from the kidney. Normally, the kidney sends phosphates to the bone through the blood. The PHEX gene defect causes the kidney to get rid of the phosphate instead of sending it through the blood, leading to a phosphorus shortage in the blood. Similar to low calcium in the blood, when the body recognizes there is not enough phosphorus in the blood, it will remove it from the bone instead. This genetic defect may also prevent the kidneys from processing vitamin D, which is necessary for the body to absorb calcium. Women are twice as likely as men to have the X-linked hypophosphatemic disorder.

When there is less calcium or phosphorus in bone, the bone and the bone’s growth plate become weak. This weakening of bone can lead to slow growth. In severe cases, children can have seizures from calcium deficiencies or develop fractures in weakened bone.

Treatment

Treatment depends on which mineral is deficient. Determining treatment may require the assistance of an endocrinologist. Once the deficiency is known, treatment involves replacing the mineral – whether it be calcium, vitamin D, phosphorus or a combination of these minerals. In many cases, the bone changes are reversible. In more severe cases, children may continue to have growth delays and crooked. Occasionally, bones become so crooked that they may require surgery for correction.

Treatment for rickets depends on which mineral deficiency your child has. This may require the assistance of an endocrinologist. Once your child’s doctor determines the mineral deficiency, treatment involves replacing the mineral – whether it is calcium, vitamin D, phosphorus, or a combination of these. In many cases, the bone changes that happen with rickets get better with time. In more severe cases, children may continue to have slowed bone growth and bones that are somewhat crooked. Occasionally, bones become so crooked that they require surgery to correct.