Hydrocephalus is an abnormal accumulation of cerebrospinal fluid within the ventricles of the brain. Cerebrospinal fluid is produced in the ventricles of the brain, circulates through the ventricular system and is absorbed into the bloodstream. Cerebrospinal fluid circulates continuously and serves many important functions. It surrounds the brain and spinal cord and acts as a protective cushion. Hydrocephalus occurs when there is an imbalance between the amount of cerebrospinal fluid produced and the rate at which it is absorbed. As cerebrospinal fluid builds up, it causes the ventricles of the brain to enlarge and the pressure inside the head to increase; the cause of hydrocephalus is unknown. Congenital hydrocephalus (present at birth) is thought to be caused by a complex interaction of environmental and genetic factors. Stenosis of the aqueduct and spina bifida are two examples, acquired hydrocephalus may be caused by intraventricular hemorrhage, meningitis, head trauma, tumors, and cysts, and it is thought that hydrocephalus occurs in about two out of 1,000 births. The incidence of adult hydrocephalus and acquired hydrocephalus is unknown. Diagnosis: Hydrocephalus is an abnormality, not a disease, so it is important to investigate the cause of hydrocephalus and the diagnosis of hydrocephalus is best confirmed by magnetic resonance imaging (MRI) of the brain. A CT scan of the brain can also diagnose hydrocephalus. (However, in most cases, an MRI is required.) In infants, ultrasound can also be used for initial diagnosis. Symptoms: Signs and symptoms of hydrocephalus vary with age and severity: Infants and young children: large head, poor diet, vomiting, sleepiness, irritability, downward shifting of the eyes (also known as the “sunset sign”), seizures in both children and adults, vomiting and nausea after a headache, optic papillae edema, blurred vision, double vision (diplopia), sunsetting of the eyes (the sunset sign), problems with balance, and blurred vision. ), problems with balance, poor coordination, sleepiness Elderly: (normal pressure hydrocephalus), progressive mental disorders and dementia, unsteady gait, impaired bladder sphincter leading to frequent urination and/or incontinence Treatment: There is no definitive prevention or treatment for hydrocephalus. The most effective treatment is shunting, and endoscopic third ventriculostomy is increasingly used as an alternative treatment for hydrocephalus.