I would lean towards doing an xray first. Dogs with LS typically have small livers, and the xray would also show any disk, back, neck, or head problems, which can be a cause of his legs going out from under him.
Are his symptoms worse right after he eats? Does he press his head against walls, or do any circling, pacing back and forth, inability to settle down for any length of time? Has he had any falls, or walked into anything?
If his liver enzymes are elevated, putting him on Denamarin or a similar product will help to protect and regenerate his Liver, LS or no. |