Summarize this article in one sentence.
Canine stroke typically occurs when blood vessels in the brain rupture (hemorrhagic stroke) or become blocked (ischemic stroke). The symptoms of canine stroke may appear quite suddenly, and may also be different from the typical signs of stroke in humans. Your dog may have had a stroke if it:  Walks in circles for no apparent reason. Holds its head tilted to one side. Turns the wrong way when called. Has difficulty balancing, standing, or walking. Experiences extreme lethargy. Has sudden problems with bladder and bowel control. Shows signs of loss of vision. Suddenly collapses. You may also notice your dog’s eyes moving rapidly from side to side as if following a moving object (nystagmus). Stroke is only one possible cause of nystagmus, but it is always a good idea to get this symptom evaluated by a vet. You can help your vet diagnose canine stroke and identify potential underlying causes more quickly by letting them know if your dog has any common risk factors for stroke. Stroke may be more likely to occur in elderly dogs and dogs with a history of:  Head injury or trauma. Heart disease. Diabetes. Kidney disease. Endocrine disorders, such as thyroid disease or Cushing’s disease. Brain tumors. Exposure to some types of poison. Certain parasites or tick-borne diseases, such as Rocky Mountain Spotted Fever. If you suspect your dog has a stroke, take them to the vet immediately. Tell your vet about your dog’s symptoms and health history. In addition to examining your dog and observing their behavior, your vet may use imaging tests as an MRI, CT scan, or standard X-rays in order to confirm or rule out a stroke.  Your vet may perform other tests, such as a spinal tap, in an effort to check for other conditions and diseases with similar symptoms. The vet will be looking for bleeding, clots, inflammation, or masses in the brain. Treat any symptoms of stroke as a medical emergency. Early medical intervention may help ensure the best possible outcome for your dog.

Summary:
Look for the symptoms of canine stroke. Assess your dog’s risk factors for stroke. Bring your dog to the vet’s office for testing.