- Last Updated: August 10, 2016
Hydrocephalus is a condition involving the build-up of cerebrospinal fluid (CSF) in the ventricles of the brain. Normally located in both inside the ventricles and around the brain tissue, CSF allows the brain to float inside the skull, acting as a “shock absorber” to prevent injury, and helps deliver nutrients, remove waste products and maintain constant pressure inside the brain. When too much CSF accumulates in the ventricles, the resulting pressure can damage brain tissue and impair brain function.
While hydrocephalus usually occurs in infants or older adults, it can present at any age. The causes are not well understood but can result from genetic abnormalities, developmental disorders, intraventricular hemorrhage, meningitis, tumors or traumatic brain injury. In infants, common symptoms include an unusually large head, fatigue, vomiting and seizures. Older patients, who have less ability to compensate for increased intracranial pressure, are known to experience dizziness, blurred vision, nausea, loss of motor function and changes in cognition and personality.
Hydrocephalus is currently treated by one of two invasive surgical procedures. The first procedure involves inserting a shunt (drain) to direct CSF from the brain to another area of the body (abdomen, heart) where it can be absorbed in the circulatory system. These drainage systems are not perfect and often require constant monitoring for the duration of a patient’s life. Infection, mechanical failure and blockages can all disrupt the shunt’s ability to properly regulate the flow of CSF. In cases where the shunt fails, surgery is required to replace the shunt.
Another less common surgical procedure to treat hydrocephalus is called an endoscopic third ventriculostomy and is effective only for patients whose hydrocephalus is due to a blockage in the ventricle system. During the surgery, a small hole is made in the third ventricle to divert the CSF around the blockage. As with any surgical procedure, complications may arise from infection and bleeding. However, the risk of infection is smaller than for a plastic shunt because there is no foreign object permanently residing inside the body.
Focused ultrasound is not currently available as a treatment for hydrocephalus but it has been explored as means of performing a completely non-invasive third ventriculostomy. A pre-clinical feasibility study was conducted at the Sunnybrook Research Institute in Toronto, Canada. Researchers were able to show that it is possible to create small holes in the third ventricle using focused ultrasound. However, further studies are needed to evaluate the safety and efficacy of this procedure before research can proceed to the clinical stages.
Alkins R, Huang Y, Pajek D, Hynynen K. Cavitation-based third ventriculostomy using MRI-guided focused ultrasound. J Neurosurg. 2013 Dec;119(6):1520-9
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