When it comes to veterinary emergencies, one of my favorites to treat is the "old dog stroke." In other words, your dog suddenly looks drunk, is acutely unable to walk, and is potentially rolling, flailing, and falling to his or her side.
The reason why I like treating these? Because the cause often has a happier ending than many of my other life-threatening emergencies that I treat. I’ve had clients call the ER frantically, stating that their dog has had a stroke. These pet owners are often prepared to euthanize their dog based on the severity of their signs, only to thank me days later when their dog returns to almost normal!
In humans, strokes can be life-threatening and severely debilitating. They typically occur due to lack of blood flow ("ischemic" injury) or acute blood vessel abnormalities. Dogs, on the other hand, develop strokes from different reasons: fibrocartilagenous emboli (FCE) or "old dog vestibular disease."
Fibrocartilagenous emboli occur when microscopic pieces of cartilage and fibrous tissue develop in the body and break off somewhere, blocking blood flow to the spinal cord by occluding the spinal cord’s blood vessels. Signs of FCE are acute and usually more unilateral (worse on one side than both sides), and are seen more commonly in certain breeds, such as miniature schnauzers, Shetland sheepdogs, and Labrador retrievers. Unfortunately, there is no cure for an FCE, and nursing care and supportive care are necessary to help your dog improve, as recovery from paralysis may be gradual and slow. Just like with humans affected by strokes, some dogs can have permanent neurologic deficits.
The other, "happier" reason for a stroke in a dog is old dog vestibular disease. This is an acute inflammation of the vestibular nerve. This nerve, which runs through the inner/middle ear and stems from the brain, helps us all to stay physically balanced. It’s also the same nerve that makes you and your dog carsick.
Old dog vestibular disease occurs acutely for several reasons: sticking a Q-tip in your dog’s ear (bad owner!); cleaning your dog’s ear with liquid ear medications; from ear infections, trauma, or thyroid problems; or, just simply, for no reason except the fact that your dog is old.
When dogs develop old dog vestibular disease, it’s the doggy equivalent to tinnitus. Signs include sudden imbalance, falling over to the side, not being able to walk, vomiting, nausea, rolling or circling to one side, and abnormal sudden eye movement (called a nystagmus).
So what's the "good" news with old dog vestibular disease? The important "walking" reflexes called conscious proprioception (CP) reflexes are normal, meaning the brain isn’t directly affected. With old dog vestibular disease, signs usually resolve within 2-3 days with marked, sudden improvement — as suddenly as it came, it’ll go away! Your dog may be left with a mild head tilt, making him look eternally curious and perplexed (and even cuter).
Dr. Justine Lee