Strokes in dogs happen when blood flow to part of the brain is suddenly cut off or when a blood vessel in the brain ruptures. About 50 percent of dogs who have a stroke have an identifiable underlying disease driving the event, and roughly 30 percent have high blood pressure at the time of diagnosis. Unlike in humans, the clot-blocking type of stroke is far more common in dogs than the bleeding type.
Two Types of Canine Stroke
An ischemic stroke occurs when an artery or vein inside the brain becomes blocked, starving brain tissue of oxygen. This is the more common form in dogs and tends to affect smaller, more defined areas of the brain. A hemorrhagic stroke occurs when a blood vessel in the brain ruptures and bleeds into surrounding tissue. Bleeding strokes generally affect larger areas and tend to be more severe.
In some cases, an ischemic stroke can convert into a hemorrhagic one. Blood leaks from damaged vessels after the initial blockage, compounding the injury. This progression can happen within hours and is one reason veterinarians monitor neurological status closely in the first day or two.
The Most Common Underlying Causes
Cushing’s disease and chronic kidney failure are the two conditions most frequently linked to strokes in dogs. Cushing’s disease causes the body to overproduce stress hormones, which thickens the blood and promotes clot formation. Chronic kidney disease raises blood pressure and disrupts the body’s ability to regulate clotting factors, both of which increase the odds of a vascular event in the brain.
Other conditions that raise stroke risk include:
- Heart disease and heartworm: Both can send clots from the heart into the brain’s blood supply.
- Hypothyroidism: Low thyroid function can cause cholesterol plaques to build up in arteries, similar to what happens in humans with atherosclerosis.
- High blood fat levels: Miniature Schnauzers are particularly prone to elevated triglycerides, which damage blood vessel walls.
- Cancer: Tumors can interfere with circulation directly or make blood more prone to clotting.
- High blood pressure: Systolic pressure above 180 mmHg puts dogs at severe risk for organ damage, including stroke. Values above 150/95 already pose some risk.
Phenylpropanolamine, a medication sometimes prescribed for urinary incontinence in dogs, has been implicated in rare cases of vascular accidents. If your dog takes this medication, it’s worth discussing the risk with your vet, especially if other risk factors are present.
Breeds With Higher Risk
Greyhounds have a notably elevated stroke risk. A study published in the Journal of the American Veterinary Medical Association found that Greyhounds were 6.6 times more likely to be diagnosed with an ischemic stroke than all other breeds combined. Cavalier King Charles Spaniels have also been identified as overrepresented in stroke cases, likely related to their predisposition to heart disease. Miniature Schnauzers face added risk through their tendency toward high blood fat levels.
What a Stroke Looks Like
Symptoms appear suddenly and depend entirely on which part of the brain loses blood flow. A stroke affecting the front of the brain can cause seizures, circling, head pressing against walls, a drunken or wobbly gait, weakness on one side of the body, or a noticeable change in alertness or behavior. When the stroke hits deeper brain structures, you might see crossed eyes, a head tilt, or loss of normal eye reflexes. Strokes in the cerebellum produce tremors during movement, exaggerated or poorly measured steps, and sometimes a rigid posture with the head twisted backward. Brain stem strokes are the most alarming, potentially causing weakness in all four legs, altered consciousness, and problems with reflexes in the head and face.
Many dog owners assume their pet is having a stroke when they actually have vestibular disease, a much more common condition that causes head tilting, falling to one side, and rapid back-and-forth eye movements. While a stroke can produce these same signs, vestibular disease is usually not caused by a blood vessel problem and often resolves on its own. The distinction matters because treatment and outlook differ significantly.
How Strokes Are Diagnosed
MRI is the gold standard for confirming a stroke in dogs. A specific type of MRI sequence called diffusion-weighted imaging can detect an ischemic stroke within hours of onset, before it becomes visible on standard scans. Veterinarians look for areas where water movement in brain tissue is restricted, a signature of cells dying from oxygen deprivation. For hemorrhagic strokes, another MRI technique highlights areas of bleeding as dark signal voids. A follow-up MRI may be performed within a day or two to check whether the stroke is expanding or converting from ischemic to hemorrhagic.
Beyond imaging, vets typically run bloodwork and check blood pressure to identify the underlying condition responsible. Finding and treating the root cause is critical to preventing another stroke.
Treatment and What to Expect
There is no canine equivalent of the clot-busting drugs used in human emergency rooms. Treatment focuses on three goals: stabilizing basic body functions like oxygen levels, blood pressure, and hydration; protecting brain cells from further damage; and identifying and managing whatever underlying disease triggered the stroke.
For hemorrhagic strokes, the priority shifts to controlling brain swelling. If pressure inside the skull rises dangerously, medications can be given intravenously to draw fluid away from the brain. In rare cases with large bleeds and rapidly worsening neurological signs, surgery to remove the blood collection may be considered.
Dogs that have had a stroke from a known cardiac source may be placed on low-dose aspirin therapy to reduce the chance of future clots. Most of the treatment, though, is supportive: keeping the dog comfortable, monitoring for worsening signs in the first 24 hours (when brain swelling peaks), and beginning rehabilitation as the dog stabilizes.
Recovery and Long-Term Outlook
The first 30 days are the critical window. In one study tracking 22 dogs after ischemic stroke, about 23 percent died within the first month. Among those that survived past 30 days, the median survival time was 505 days, well over a year. Forty-one percent of 30-day survivors were eventually assessed as having an excellent clinical outcome, meaning they returned to near-normal function.
Location matters. Dogs with strokes on the right side of the brain had significantly worse outcomes, with a median survival of just 24 days compared to 602 days for left-sided strokes. The reason for this difference isn’t fully understood.
If your dog’s neurological signs are going to worsen, it typically happens within the first 24 hours due to progressive swelling around the damaged tissue. After that initial period, gradual improvement is the more likely trajectory. However, about 40 percent of 30-day survivors in the same study eventually developed a poor outcome, and roughly a third experienced new acute neurological signs within 6 to 17 months, with some confirmed as repeat strokes on MRI. This is why managing the underlying disease, whether it’s Cushing’s, kidney failure, or high blood pressure, is just as important as treating the stroke itself.