“Old dog disease” – another name for canine vestibular disease:
https://www.petmd.com/dog/conditions/neurological/vestibular-disease-dogs

Canine idiopathic vestibular disease, which is also sometimes called “old dog disease” or “old rolling dog syndrome,” can be very scary for pet parents. To the untrained eye, the symptoms may mimic serious, life threatening conditions such as stroke or a brain tumor.
The good news is that this condition, which is described by veterinarians as fairly common, typically disappears in a matter of days.
VCA Animal Hospitals define vestibular disease as a sudden, non-progressive disturbance of balance.

“Idiopathic refers to the fact that veterinarians can’t identify the source of the balance issue,” said Dr. Duffy Jones, DVM, a veterinarian with Peachtree Hills Animal Hospitals of Atlanta in Georgia. “There are a lot of theories such as inflammation, but as with some humans who suffer from vertigo, we really don’t know the cause.”

Dr. Keith Niesenbaum, DVM, a veterinarian with Crawford Dog and Cat Hospital in Garden City Park, New York, and who has been practicing for 32 years, said that idiopathic vestibular disease is more common in older dogs and there really isn’t a breed that is immune.
“Anecdotally, I’ve seen it more in large breed dogs, but it can also happen with small breeds as well,” Niesenbaum said.

Symptoms of Idiopathic Vestibular Disease: 
Deb Hipp of Kansas City, Missouri, was preparing to go out of town for a few days when her 17-year-old dog, Toby, suddenly had more trouble than normal getting up. “He has some mobility issues, so I thought he was just tired, so I waited another ten minutes and tried to get him up,” Hipp said. “On the second attempt, he was having trouble placing his paws to stand and I immediately took him to the emergency vet.” Hipp thought Toby might have had a stroke, but the veterinarian made a note of Toby’s eyes, which were darting back and forth. After some blood tests and a more thorough exam, he diagnosed idiopathic vestibular disease. By that time, in addition to not being able to stand and the darting eyes, Toby also displayed other symptoms of the disease, which include:
–  Head tilt, which may be slight to extreme
–  Acting dizzy and falling down, which may remind people of someone who is drunk
–  Nausea and/or vomiting
–  Dogs may also turn in circles or roll

“The symptoms are acute, or immediate,” said Jones. “The symptoms will not be a slow progression but happen all of a sudden. There really aren’t any symptoms that can be a sign this is coming on.”

Medical Treatment for Idiopathic Vestibular Disease:
Jones said it is important to get your dog to its veterinarian as soon as you see any of the signs, as the symptoms are similar to that of other more serious conditions, such as an inner ear infection, stroke, brain tumor, or seizure. Jones said idiopathic vestibular disease is confirmed by a veterinarian upon a complete physical examination, such as checking the eye movement, which would be rolling in cases of a stroke, and lifting the paw and flipping it over to see if the dog puts his paw back. “If the dog can flip his paw over, it typically isn’t a stroke,” said Jones. Niesenbaum said that once the condition is diagnosed, the dog is typically treated at home unless the dog is vomiting and is at risk of dehydration, at which point he will hospitalize the dog so it can be put on IV fluids. “If the dog goes home, we will typically prescribe an anti-nausea medication and something to help with dizziness,” Niesenbaum said.

Home Treatment for Idiopathic Vestibular Disease:
Jones said that dogs can eat, but due to the nausea, they may not want to eat. He added that it is important to watch for hydration issues. Other concerns include keeping the dog in a confined area, and not allowing them to climb stairs or be on the furniture. “The dog will really be off balance and if there are stairs or he gets on the furniture, he may fall and break bones,” said Jones. Another consideration, especially if it is a large dog, is getting the dog outside to go to the bathroom. This was a big concern for Hipp, whose dog, Toby, weighs 60 pounds. “Toby had mobility issues, so I had bought a special harness to help him up,” said Hipp. Still, when Toby was in the first days of idiopathic vestibular disease, he was dead weight, not being able to stand or walk at all. After conferring with her veterinarian, Hipp was advised to hospitalize Toby. “I was leaving town and didn’t want to leave him with the pet sitter. Although we were convinced Toby would recover, I didn’t want her to have to pick him up and take him outside,” said Hipp. Niesenbaum said if you don’t have a harness, you can use a towel as sling to help your dog stand.

The good news is that like most dogs with this condition, Toby completely recovered within a matter of days and now even goes on his daily short walk. “It can sometimes take a couple of weeks, but if they’re not improving after 72 hours, we know it could be something more serious,” said Jones. Some dogs do not recover completely from the head tilt. Even if your dog has appeared to have completely recovered, it’s important for the dog’s veterinarian to see the dog again just to be sure. “I don’t get to give a lot of good news to owners of geriatric dogs when they have serious conditions, but this really is the ‘good news’ condition in that most dogs will survive and recover completely,” Jones said.