1.What is hydrocephalus? Hydrocephalus is a large amount of cerebrospinal fluid that collects in the ventricular system and can lead to increased intracranial pressure and enlarged ventricles. This is not just one disease; hydrocephalus can be caused by a variety of reasons. Any disease that causes an increase in the amount of cerebrospinal fluid in the skull due to excessive cerebrospinal fluid secretion or impaired cerebrospinal fluid circulation or absorption can cause hydrocephalus. In Chinese medicine, hydrocephalus is called “craniosynostosis”. 2.What is cerebrospinal fluid? Cerebrospinal fluid is produced continuously in the ventricles of the brain. It flows around the brain and spinal cord, is absorbed, and then replaced by new cerebrospinal fluid. The functions of cerebrospinal fluid are: (1) to protect the brain and spinal cord from damage; (2) to nourish brain cells and help the brain perform its functions; (3) to carry away waste products produced by brain cells; cerebrospinal fluid flows around the brain and spinal cord along specific pathways. When too much cerebrospinal fluid builds up along the pathways, it causes the ventricles to swell and compress the brain. This condition is known as hydrocephalus. 3. What are traffic and non-traffic hydrocephalus? There are two types of hydrocephalus: (1) Traffic hydrocephalus: The accumulation of excess cerebrospinal fluid because it is not properly absorbed. (2) Non-traffic hydrocephalus: When the cerebrospinal fluid channels in the brain become blocked, the pressure increases. Some non-traffic hydrocephalus may be caused by a tumor, a blood clot, or a part of the cerebrospinal fluid pathway that was narrowed at birth. 4. Why does my child have hydrocephalus? The usual causes of hydrocephalus are: (1) Congenital malformations: such as stenosis of the midbrain aqueduct, diaphragm formation or atresia, atretic malformation of the interventricular foramen (median foramen of the fourth ventricle or lateral hollow atresia), cerebrovascular malformation, spina bifida, and submicrocephalic tonsillar herniation. (2) Infection: Intrauterine infection such as various viral, protozoal and syphilitic spirochete infectious meningitis is not controlled early enough, and the proliferating fibrous tissue blocks the circulatory orifice of cerebrospinal fluid, or intracranial inflammation of the fetus may also cause adhesions and occlusion of the brain pool, subarachnoid space and arachnoid granules. (3) Hemorrhage: fibrous hyperplasia caused by intracranial hemorrhage, malabsorption of intracranial hemorrhage from birth injury, etc. (4) Tumors: can obstruct any part of the cerebrospinal fluid circulation, more commonly seen near the fourth ventricle, or choroid plexus papilloma. (5) Other: certain hereditary metabolic diseases, perinatal and neonatal asphyxia, severe vitamin A deficiency, etc.