Hydrocephalus is caused by the continuous increase of cerebrospinal fluid in the ventricular system of the brain. There are two types of hydrocephalus: obstructive hydrocephalus and communicating hydrocephalus, each with different treatment methods. Obstructive hydrocephalus is caused by obstructions such as tumors or blood clots, so removing tumors or clearing blood clots can relieve the obstruction and treat the hydrocephalus. On the other hand, communicating hydrocephalus usually has no obstruction; it is primarily caused by excessive production or insufficient absorption of cerebrospinal fluid. A common treatment is ventriculoperitoneal shunt surgery, which diverts cerebrospinal fluid from the ventricles to the abdominal cavity to treat hydrocephalus.