Traumatic brain injury is a common cause of hydrocephalus, which is often secondary to heavy craniocerebral injury. The cause of hydrocephalus is the accumulation of blood in the subarachnoid space and intraventricular space after traumatic brain injury, the blood clots block the conduit and the outlet of the fourth ventricle, which affects the circulation of cerebrospinal fluid, resulting in intracranial hypertension, or the subarachnoid villi are blocked by the red blood cells and adhered, which prevents the absorption of cerebrospinal fluid. Post-traumatic hydrocephalus is divided into two categories: acute and chronic. Acute hydrocephalus Acute hydrocephalus is mostly obstructive hydrocephalus, which is a pathological phenomenon caused by the obstruction of the cerebrospinal fluid circulation pathway above the fourth ventricle, so that the cerebrospinal fluid flows into the subarachnoid space (or cerebellar medullary pool) pathway is obstructed. Simply put, it means that a certain part of the fluid circulatory system in our brain is blocked, resulting in excessive accumulation of fluid in the brain, which affects the brain function and produces corresponding clinical symptoms. 2. Chronic hydrocephalus Chronic hydrocephalus is mostly traffic hydrocephalus, which is a pathological phenomenon caused by malabsorption or excessive secretion of cerebral crural fluid and impaired excretion. Simply put, it means that the fluid inside the cerebral chamber cannot be absorbed normally or is secreted excessively, resulting in more fluid coming in than going out, and the fluid accumulates in the brain. Doctor’s tip: Whether it is acute hydrocephalus or chronic hydrocephalus, the clinical symptoms are similar, mainly headache, vomiting, mental indifference, slow reaction and urinary incontinence clinical phenomenon, may appear alone, but more often contain more than two manifestations, need to pay attention to, and once appeared, respond to the doctor in a timely manner.