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Did My Dog Have a Stroke?

Dog stroke symptoms may include the following

  • Head tilt

  • Deafness in one or both ears (temporary or permanent)

  • Turning the wrong way when called

  • Eating out of one side of his food bowl

  • Loss of balance

  • Lethargy

  • Blindness (temporary or permanent)

  • Loss of bladder and bowel control

  • Sudden behavioral changes

Stroke (cerebrovascular accident)

Until recently, it was thought that strokes were very rare in domestic pets. In the last few years, with the advance and increased availability of more specialist tests, strokes are being recognized more often in pets.

The thought of your pet suffering a stroke may be frightening - but you should not be alarmed - strokes are often not as debilitating in animals as they are in people. With appropriate care your pet may do very well.

What is a stroke?

A stroke or cerebrovascular accident is the term used for the signs shown by an animal when the blood supply to the brain is reduced. There are two types of stroke:

  1. Ischemic stroke is caused by a sudden lack of blood supply to the brain and
     
  2. Hemorrhagic stroke (or bleeding within the brain) is caused by a burst blood vessel.

More than any other organ, the brain relies on a constant blood supply to bring oxygen and nutrients and to remove waste products. If the blood supply to the brain fails brain function is severely disrupted (ischemia) or parts of the brain destroyed (infarct) in a specific region of the brain fed by the affected artery.

The diseases causing ischemic stroke can be broadly divided into those diseases causing narrowing of an artery (thrombosis) and diseases causing clogging of an artery by material coming from somewhere else in the body (embolism).

In hemorrhagic strokes there may be leakage of blood within the brain tissue itself (intraparenchymal hemorrhage) or between the brain and the skull (subdural or subarachnoid hemorrhage). The site of the bleeding depends on the location of the affected blood vessel.

How do I know if my pet has had a stroke?

The signs of strokes in dogs and cats are often very different from those seen in man. In human stroke victims a drooping face or total paralysis on one side of the body are common signs but these are rarely associated with stroke in dogs and cats. More common signs include head tilt or turn, loss of balance, loss of vision, circling and falling. These signs are not specific for stroke and can be seen associated with other brain disease.

How will my vet know that my pet has had a stroke?

Your vet may suspect that your pet has suffered a stroke from the signs your pet is showing. In order to make a definite diagnosis your vet will need to do some further tests including imaging your pet's brain. In order to get a picture of the inside of the brain specialist scans such as CT (computed tomography) or MRI (magnetic resonance imaging) are needed. It is not possible to make this diagnosis using standard X-rays.

These tests require that your pet be anaesthetized and this will also allow a sample of spinal fluid (spinal tap) to be taken to check for other potential diseases that could cause similar signs.

A diagnosis of stroke can be based on identification particular changes in the brain and ruling-out other diseases that could mimic a stroke (inflammation or infection of the brain, bleeding from a brain tumor or a metastatic tumor spreading to the brain). Once the diagnosis of stroke has been made, further tests will be needed to look for potential underlying causes for the stroke.

What causes strokes in dogs?

Ischemic strokes have been associated with many medical conditions in dogs and cats: kidney disease, heart disease, under or over-active thyroid glands, Cushing disease, diabetes and high blood pressure (hypertension).

Other less common causes of blockage of the blood vessels supplying the brain include clogging by a fragment of tumor, fat, parasites or spinal cartilage.

Despite thorough investigations, an underlying cause is not found in more than half of dogs with stroke.

Hemorrhagic strokes can be seen with diseases that interfere with blood clotting (angiostrongylosis (a kind of lung worm), some rodent poisons (warfarin-like products), immune-mediated thrombocytopenia, and congenital clotting diseases), disease causing high blood pressure (kidney disease, heart disease, Cushing's or thyroid disease), inflammation of the arteries (vasculitis) or abnormal development of the blood vessel in the brain. Other causes of bleeding in the brain include head trauma, bleeding from a brain tumor or from a tumor spreading to the brain (especially common with tumours of the spleen).

Is there any treatment for stroke?

Once a stroke has occurred there is no specific treatment that can repair the damage done to the brain. Efforts should be concentrated on identifying a potential cause for the stroke and, if a cause is found, treating it to prevent further strokes. Good nursing care is essential for recovery.

Will my pet get better?

Although there is no specific treatment for stroke, most dogs and cats tend to recover within a few weeks. However recovery may not be possible if the stroke has affected a vital part of the brain. The long-term outlook and chances of another stroke depend on what has caused the stroke and whether this can be treated.

You may need to encourage your pet to eat, and drink soon after he has suffered from a stroke, and help him onto his feet, and encourage him to take bathroom breaks outside.

Exercise, especially strenuous exercise, should be avoided. Once your dog is feeling well enough, he will soon tell you when he is ready to start going on walks again. After a matter of weeks, he will be starting to get back to his old self.

Don’t forget that once your dog has recovered, he will still need plenty of love, and encouragement, and may not be as agile as he was before the stroke. Strokes can keep reoccurring in dogs, so keep a close eye on him. 

See also: Vestibular Syndrome (disease)