looks like we may have 2 problems!
if your dog did improve on lactulose, it maybe that some of the symptoms are due to a liver shunt. If the lactulose does not work anymore, the liver shunt and/or the hydrocephalus could be the culprit. we won't be able to tell.
Here is a link about hydrocephalus:
It is hard to tell if he is painful, probably his mentation is just not normal.
As for hydrocephalus treatment:
-Shunt surgically implanted (different surgery techniques). Symptoms can be helped. If some permanent damage is not done, some symptoms may not improve. Complications includes infection, which has a lower rate then in humans. Some will clog after a year (10-15 % for certain practices). Needed if severe disease.
-Prednisone or dexamethasone. Yes, long term it may induce Cushing symptoms, but dogs may get a better quality of life for several months/years depending of how severe their condition is. It will not slow down the progression of the disease process. not sure it is very good for the liver problem though! but you may have no choice!
-Some neurologist also use Furosemide. Some thinks it does not work well.
-Acetazolamide: does decrease the CSF fluid formation, but it's use is limited due to the fact the blood becomes very acid.
You may want to continue the lactulose, and maybe even ask about adding some antibiotics like amoxicillin. If the liver is of concern, a low protein/high quality protein diet might be better instead of the brain diet!
I hope all this discussion can help you communicate with your primary care veterinarian and/or the neurologist to find what will be the best approach for Chewie.
i will hope for the best!
Let me know if you have more questions, or need additional information.
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