Subdural hematomas are more common in infants and children, and there are several common causes. 1, birth injury, that is, the fetus through the mother’s birth canal when extrusion injury. If the fetus is large or the mother has a small pelvis due to low size, the head of the fetus is repeatedly squeezed during delivery, making the cranial suture large and small, or even squeezing the two bones together, resulting in bleeding due to strain injury to the brain surface vessels or meningeal vessels. Sometimes intracerebral hematoma will be formed. 2.Vitamin k1 deficiency Vitamin k1 deficiency directly leads to a decrease in coagulation function, resulting in bleeding from rupture of subdural blood vessels or brain surface or intracerebral blood vessels and formation of subdural hematoma. Vitamin K deficiency leads to bleeding because the coagulation ability of blood clotting factors 2, 7, 9 and 10 directly depends on the presence of vitamin K1 in order to play the coagulation activity, lack of vitamin K, the above four coagulation factors can not participate in the coagulation process, and bleeding is likely to occur. 3, other coagulation function problems such as platelet low. Prognosis and sequelae: Vitamin K1-deficient subdural hematoma usually does not recur after treatment with vitamin K1 supplementation. Most hematomas are cured by drainage, but a very small percentage of infants and children develop subdural fluid, and hydrocephalus may form later if the hematoma breaks into the ventricle. Subdural effusion can be gradually improved by hyperbaric oxygen therapy, treatment to improve circulation, and lumbar puncture. If hydrocephalus worsens during observation, surgical treatment is required.