While in people the symptoms of a stroke are often dramatic, in dogs they can be subtle and may be overlooked or confused for something else.
Common symptoms include:
lack of appetite (caused by feeling nauseous)
loss of balance
loss of vision (possibly only on one side)
walking in circles
eyes flicking from side-to-side
behavioural changes (whining, seeking attention, aggression)
loss of basic training which could include incontinence
difficulty learning new things or struggling to focus on a task (most noticeable in dogs that compete in a dog sport which requires regular training)
seeming 'spaced out' or in a daze
dragging a hind leg or limping on a front leg
The type of symptoms a dog will display after suffering a CVA depends greatly on the severity of the stroke, what has caused it and where it occurs in the brain. Many owners only realize their pet is unwell when it suffers a severe stroke with dramatic symptoms, such as seizures and paralysis. They may later recall their pet having other, milder symptoms of stroke before this incident, which at the time they did not realize was significant or associated with their pet naturally aging.
CVA symptoms are often confused with Vestibular Disease, which causes a number of the same symptoms (head tilt, loss of balance, turning in circles). The vestibular system is responsible for balance and is located in the brain and the inner and middle ear.
Confusingly, a CVA can actually trigger a vestibular problem if it affects the portion of the brain associated with the vestibular system and sometimes Vestibular Disease is referred to as a canine stroke, which is incorrect. Vestibular Disease can occur due to an ear infection, head trauma, a tumor, or sometimes for no obvious reason. It is generally self-resolving without treatment and is not fatal, although it may be an indication of something else that could be life-limiting.
In contrast, CVAs are more serious as without treatment they can become progressively worse and result in the death of the dog.
Other conditions that could be confused with CVAs due to the symptoms are spinal problems (dragging the hind leg), arthritis or muscle sprain (front leg limp), epilepsy (seizures, behavioral changes, disorientation) and poisoning by something toxic.
Only a vet can determine if a dog has truly suffered a CVA, as this requires specific tests not only to rule out other conditions but potentially to spot where the stroke has occurred within the brain.
How Is a CVA Diagnosed?
Since the symptoms of a CVA can mimic many other conditions, it is important to seek veterinary advice at once if you suspect your dog has had a stroke. Diagnosis is partly dependent on ruling out other possible illnesses before your dog is confirmed as having a stroke. Blood and urine samples are taken to check for underlying conditions.
Occasionally, dependent on the type of stroke, it is possible to see evidence for it during a physical exam. For instance, in a hemorrhagic stroke where a blood vessel has burst and bled into the brain, it may be able to see evidence of this if the blood has hemorrhaged behind the eye causing temporary blindness.
Unfortunately, for most cases of stroke, the only reliable way of confirming a CVA has occurred is by using an MRI machine to scan the brain. However, MRIs are expensive and usually have to be performed at a specialist vet, which puts them out of the budget of many owners.
Dogs that have one stroke, may go on to have another and each one they have tends to be more severe, this is another factor in diagnosing a CVA, though it is not so helpful if your dog has only had a single stroke.
Treatment and Recovery
Dogs recover better from strokes than people and usually in a faster time. Minor strokes that do not cause paralysis or seizure can resolve in a week, however, things such as behavioral changes may take longer to resolve and in some cases, they may be permanent.
As with people, the initial few hours and days after a stroke has occurred are critical to determining recovery. The swifter the improvement the more chance of a full recovery, but this is very dependent on how much damage was done, what was affected in the brain and whether there is an underlying condition (such as a brain tumor, which triggered the stroke).
There is no treatment for a stroke, other than to take care of the pet during its recovery and to treat any potential side-effects, such as nausea. A dog that has suffered a CVA should have a thorough medical assessment, including blood tests and heart scan, to determine if there is an underlying cause for the stroke which needs to be treated.
Risk factors for CVAs include:
heart disease (specifically congestive heart failure)
blood clotting disorders
malformations of the blood vessels
chronic kidney disease
ingestion of poisonous substances
Hyperthyroidism has also been suggested as a risk factor, but the evidence is lacking to confirm this.
, it is impossible to find an underlying trigger for the stroke. around 50% of cases
Life After a Stroke
The long-term outcome for a dog that has suffered a stroke is dependent on a number of factors, such as the severity and whether an underlying cause was found to be associated with the CVA.
Some conditions that can trigger a stroke are in themselves life threatening, such as in the case of a brain tumour or kidney disease. In these cases, palliative care may be the only option for the dog and their life expectancy will not be great.
Other causes of stroke can be managed with medication, and as a result the outlook for the dog is more promising. With the correct treatment not only will the underlying disease be controlled, but the risk of further strokes is minimised.
In situations where a cause for the stroke cannot be determined then the outcome for the dog is far more complicated. There is a high possibility of further strokes occurring, these may be minor or major events, but each will do a little more damage to the brain and may lead to permanent disability in the dog.
There is little the owner can do to prevent further CVAs, but being vigilant of the pet and taking them to the vet the instant they notice potential signs of a stroke will help.
Only a handful of studies have been done into the long-term survival rate of dogs that suffer a CVA. Partly this is due to a lack of dogs being diagnosed with the condition.
looked at 22 dogs that had been diagnosed by MRI with ischemic strokes. study published in 2012
Five dogs (23%) died within 30 days of the stroke.
In those dogs that survived beyond 30 days, the prognosis was better, with an average life expectancy of 505 days (nearly 17 months).
Four dogs (18%) lived longer than this and were still alive at the time the study concluded.
The study found that in dogs that survived beyond 30 days there was a high probability of another stroke 6-17 months after the first.
It is not all doom and gloom, however. Veterinarian
"I'd say as many as 75% [of dogs] improve or normalize with time, but it could take a week or more. I've had dogs live years after a stroke. Happy, healthy lives." Dr Todd Bishop states,
While there is still a lot we don't know about strokes in dogs, the general picture is positive and many dogs survive even quite severe strokes and return to a normal life.
Author: SOPHIE JACKSON