The head size of children is not necessarily caused by hydrocephalus, there are more reasons for the head size. First of all, the head is big due to hydrocephalus, if the children have obvious hydrocephalus, it will cause the brain circumference to increase, that is, the children’s head is bigger, this situation needs to give the children timely surgical treatment. Secondly, it is caused by vitamin D deficiency rickets. When children suffer from vitamin D deficiency rickets, it can cause calcium deficiency, which can lead to a square skull and a larger head circumference. If there is a tumor in the brain, it can also cause an increase in brain volume, and the child’s head size is progressively aggravated, and there are also symptoms such as severe headache and vomiting.