My mother had hydrocephalitis she had been “off” for a while. Thanksgiving day she was Not herself she ate with her hands,literally had no clu what was happening. The neurologist said the brain fluid was not draining properly and putting pressure on the brain causing the strange behavior. They put in a shunt to drain the extra off.they check it yearly to see if the pressure is ok. He said she should come back pretty well but would never be quite as good as before. She did. She has some decline but she’s also 87 yr old. I interpreted that to mean the pressure can cause some damage to the brain which is is dementia but I don’t think it causes it if it’s taken care of fairly quickly. That was my understanding of the situation.

Hydrocephalus is one of many causes of dementia. My husband was diagnosed with it about 5 years. He was being evaluated for dementia at that time and the fluid build-up was detected on an MRI. He had a shunt put in the brain at that time in the hopes that his dementia symptoms might be reversed.
Unfortunately, the surgery did not result in any improvement for his dementia. His neurologist subsequently diagnosed Alzheimer's as the cause of his dementia.

Maxine does your mom have dementia or did she have it before the hydrocephalitis diagnosis.

Grammybeach, thanks! This was useful and what I was looking for.
My mom already stated she did not want any kind of surgery. We have to set up appointment to see Neurologist.