I agree, at 15 years old I would doubt a liver shunt. I would think maybe something circulatory or possibly anxiety from being both blind and deaf. Bless his little heart, and yours for taking such wonderful care of your little man. Does he circle even while being walked...on leash? Give Chewy an extra kiss from me and Winston!
__________________ As Ever, Kathy 
Intruducing Bentley  Winston and Spencer: RIP My Sweet Angels |