Hydrocephalus is the condition that develops when the fluid inside in the brain gets trapped, either within the ventricular system, or somewhere outside of it, or the fluid can't be absorbed quickly enough, and it builds up, resulting in pressure on the brain. This can result in life-threatening issues, such as seizures, stroke, and ultimately even death.
So...what can be done to treat it? "Hydro," as those of us who live with it often call it, is not curable, but it's usually treated with the surgical insertion of a shunt. A shunt is a siliconized-plastic, pencil-thin (or even more recently, angel-hair thin) catheter which is inserted into the blocked ventricle (or near the location of the blockage), threaded down the neck and torso, and into the peritoneal cavity near the stomach, atrial valve of the heart, or other "ending" site. The shunt has a valve which regulates the flow of CSF (cerebrospinal fluid) so that it drains at a slow but steady rate. The fluid is then absorbed into the bloodstream and eliminated from the body with other forms of waste. Because the whole thing is inside the body, you may know someone with hydro and a shunt and were never aware.
The scary thing about hydro is that the shunt is an imperfect and man-made device, so problems are common. They often disconnect from the ventricle, clog up with CSF protein or tissue debris, or become infected, so most of us need repeat surgeries throughout our lifetime to correct such problems. Because the hydro often goes undx'ed for a time (particularly in old people like me, who couldn't be dx'ed before birth, as many can be today), some damage may already be done by the time shunting is done. Learning disabilities are common, and many of us have ongoing bouts with headaches, seizures of one type or another, balance issues, and vision problems.
I hope this helps! Please feel free to ask any questions at anytime. I'm old hat at this (nearly 40 years), and I have learned a lot.
LIZ in RI, 39 yo mom with hydrocephalus since birth; five shunt surgeries by kindergarten and just ONE since (no kiddin'! ). Epilepsy finally dx'ed in college. Mom to Caren, 15, my "assistant"; and Drewy, 12 (autism, ACM I, and sassy adolescent boy nearly as tall as his mom! ), and wife to Don, World's Most Awesome Hubby, for 16 years! And BTW...I'm SHRINKIN'!! Ask me how!