Imagine this scenario: You’re working as a vet tech at your first job, just a few months after graduation. One morning, a client rushes into the clinic in a panic, on the verge of tears.
“Help, I think Duke had a stroke! He seemed fine when I left to take the kids to school, but when I came home he was lying on the ground. He can’t even stand up without falling over! Can someone please help me bring him in?!”
You and your coworker get Duke, a 10 yo MN Labrador Retriever, from the car and carry him inside to an exam room. The client tells you that Duke had been acting completely normal.
This morning, he ate his breakfast, went outside to go potty, and took treats from his owner like he does every morning. The owner left for 40 minutes and returned home to find him lying on the floor, struggling to stay upright. When she tried to help him into a standing position, he immediately fell over.
When you perform your triage exam, you notice that Duke is ataxic and rolling to the left. He also has a head tilt and horizontal nystagmus. You reassure the client that you will have the veterinarian in to see Duke as soon as possible, then go to relay the history and triage exam findings to the veterinarian.
After the veterinarian speaks with the owner and performs her own physical exam, she tells Duke’s owner that he likely has Idiopathic Vestibular Disease. She recommends some additional testing to rule out other possible causes of his signs, but reassures the owner that she does not feel that Duke has had a stroke and that most dogs with his signs go on to do quite well.
Idiopathic Vestibular Disease goes by a number of labels, including Idiopathic Vestibular Syndrome, Geriatric Vestibular Disease/Syndrome, and Old Dog Vestibular Disease/Syndrome.
These labels tell you two important things about this condition:
Dogs with Idiopathic Vestibular Disease typically present for an acute onset of vestibular signs, developing over a period of minutes to hours. Once these signs develop, they are non-progressive and often begin improving relatively quickly (within days).
Common exam findings associated with Idiopathic Vestibular disease include:
Dogs with Idiopathic Vestibular Disease may also experience facial paralysis (drooping of one side of the face) and/or Horner’s syndrome (constricted pupil, elevated third eyelid, and sunken globe), although these findings are not always present.
Idiopathic Vestibular Disease is primarily a diagnosis of exclusion. If an older dog presents for acute, non-progressive vestibular signs and an underlying cause cannot be found, the dog is diagnosed with Idiopathic Vestibular Disease.
In order to rule out other conditions, the veterinarian must first determine that the lesion is peripheral (within the nerves) and not central (within the brain). A complete neurologic exam is typically performed, to rule out cranial nerve deficits or other abnormalities that might suggest central disease. Characteristics of the dog’s nystagmus can also help distinguish central from peripheral vestibular disease. Nystagmus that is vertical, extremely slow, or that changes directions with changes in head position all suggest a higher likelihood of central vestibular disease.
Once it is established that a dog’s vestibular signs are due to peripheral disease, the veterinarian will consider other causes of peripheral vestibular signs. Differential diagnoses may include otitis media, otitis interna, otic neoplasia, exposure to ototoxic drugs, trauma, hypothyroidism, and rickettsial disease. Recommended testing will be based on which of these conditions is deemed likely in a given patient. In some cases, testing is postponed in favor of monitoring.
The bad news is that there’s no specific treatment for Idiopathic Vestibular Disease. The good news, however, is that dogs typically recover spontaneously. Most dogs are mostly “back to normal” within a period of days to weeks, although some dogs may have a long-term residual head tilt.
The treatment of Idiopathic Vestibular Disease is centered on supportive care. Dogs may benefit from motion sickness medication, such as meclizine or dimenhydrinate. Dogs with nausea, vomiting, and/or anorexia may also be treated with maropitant or chlorpromazine. Finally, some dogs become dehydrated due to their reluctance or inability to drink; these dogs may require a period of hospitalization and intravenous fluids.
Idiopathic Vestibular Disease can be terrifying for clients, many of whom worry that their dog has had a stroke. It is important to reassure these clients that dogs are far less susceptible to strokes than humans and that vestibular signs are rarely associated with a stroke in dogs.
Once a diagnosis has been made, clients may have concerns about their ability to care for their pet. Emphasize that signs typically begin to improve within two to three days; in fact, some dogs will experience complete resolution during that time period! Most dogs only require a brief period of supportive care, even if their signs seem severe when they are presented.
If the veterinarian prescribes or recommends medication for the pet, review these medications with the client and ensure that they understand dosing and side effects. Dogs often are not eating during the initial stages of Idiopathic Vestibular Disease, so you may need to demonstrate to owners how they can administer pills at home.
Finally, discuss appropriate nursing care. For a minimally affected dog, little to no change in the dog’s daily routine may be needed. In a dog with severe signs, however, consider the following:
Vestibular signs should gradually improve over time, beginning within a few days. If signs instead begin to worsen, or if several weeks go by without improvement, it is important that the dog is brought in for a recheck to rule out other neurologic conditions. In most cases, however, dogs will be back to normal within a couple of weeks.