Jason, I'm sorry that your question wasn't answered in a timely manner. Please let me know if you still need help. Can you tell me, please, what was seen at the beginning of the month that prompted her vet to consider stroke? Her current heavy panting and agitation are not pathognomonic (specifically indicative) of stroke and can indicate any number of disorders in a 13 year old. Classic strokes in dogs will cause obtundation (altered level of consciousness) and coma but symptoms vary with the severity and location of the stroke in the brain.
Thank you for the additional information. The "old dog vestibular syndrome" should be the most important differential diagnosis. Caretakers often think that their dog has suffered a stroke when, instead, a balance disorder exists and can be represented by nystagmus (eyes flicking back and forth), head tilt, and ataxia ("drunken sailor"). A vet needs to distinguish this balance disorder from peripheral vestibular disease involving her inner/middle ear(s) and central vestibular disorder involving her cerebellum or brainstem.
A 13 year old who has experienced a second event may not recover completely. A lasting head tilt is common. There's no specific therapy for the old dog vestibular disorder. An antiemetic such as meclizine or maropitant can be prescribed if vomiting/nausea are severe. Please continue our conversation if you wish.
Blood work isn't helpful when differentiating one vestibular disorder from another but it's good to hear that it looked good at her age. Be patient with her; she can still improve but her recovery is likely to be protracted - 3-6 weeks - and incomplete. I can't set a follow-up in this venue so please return to our conversation - even after rating - with an update at your convenience. You can bookmark this page for ease of return.
Thank you for your kind accept. I appreciate it.
Thank you for the good update. I appreciate your taking the time to let me know.