By Carol McCarthy
Chances are, you know someone who has had a stroke and have seen the life-altering impact it can have. As a pet parent, you might be surprised to learn that dogs can have strokes, too.
With the increased availability of MRI and CT scans for pets, strokes are being diagnosed more frequently, says Dr. Brett Levitzke, medical director of the Veterinary Emergency and Referral Group in Brooklyn, N.Y. Understanding the causes, symptoms, and treatment of strokes in dogs will help you to be a savvy pet parent.
What is a Stroke?
Dr. Virginia Sinnott of the Massachusetts Society for the Prevention of Cruelty to Animals Angell Medical Center explains that a stroke is loss of blood flow to parts of the brain that leads to neurologic abnormalities.
There are two mechanisms that cause strokes in dogs: an obstruction in blood vessels (ischemic strokes) which occur due to blood clots, tumor cells, clumps of platelets, bacteria and parasites; and bleeds in the brain (hemorrhagic strokes), which result from the rupture of blood vessels or clotting disorders.
What a Stroke Looks Like in a Dog
Signs of strokes in animals can be similar to those in people, though animals obviously do not suffer from slurred speech or loss of memory, and symptoms vary depending on the location in the brain where the stroke occurred, Dr. Levitzke says.
“Even in people, these signs can be subtle, and since animals can’t speak and tell us they ‘feel dizzy’ or ‘I can no longer see out of my left eye,’ subtle true strokes can go unnoticed in animals,” Dr. Sinnott says.
However, it is more common to see massive strokes in dogs, she says, and pet parents sometimes mistake fainting spells (syncope) for strokes. “Both are very serious and require immediate attention by a veterinarian,” Dr. Sinnott says.
Symptoms of strokes in dogs can include:
- Inability to walk or walking with an uncoordinated gait
- Head tilt
- Abnormal eye movements, side to side or rotary (nystagmus)
- Abnormal eye positioning (strabismus)
- Loss of consciousness
- Abnormal behavior
- Falling to one side
- Abnormal behavior
- Rapid onset of symptoms
“Generally, one minute owners report the pet is fine, and the next [the pet] cannot get up. These signs may last for a few minutes or much longer (hours to days),” Dr. Sinnott says.
Causes of Strokes in Dogs
Dr. Sinnott says vets typically see only a couple of cases of strokes in dogs every year, and when they do occur, it is usually in a very old dog who has diseases that can increase the risk of clots or bleeding.
“The signs can be frightening and may be associated with discomfort for the dog, and some owners elect to euthanize their pets,” Dr. Sinnott says in the cases of strokes in very old dogs.
The underlying diseases that can cause strokes in dogs include kidney disease, Cushing’s disease (hyperadrenocorticism), hypertension, diabetes, heart disease, bleeding disorders, hypothyroidism, cancer, and in some cases, high doses of steroids, such as prednisone, can lead to stroke. While no one breed is more likely to suffer a stroke than another, breeds that are prone to some of the underlying diseases that cause them might be predisposed to strokes, such as King Charles Cavalier Spaniels, which have a high rate of heart disease, Dr. Levitzke says.
Treatment Begins with Diagnosis
Proper diagnosis is the most important part of treating strokes in dogs. A fainting spell that might look like a stroke can be caused by abnormal heart rhythm, which can be life threatening. Your vet can distinguish a stroke from a fainting spell by examining your dog’s heart functions to rule out a cardiac problem. Tests may include an electrocardiogram (ECG), chest X-rays, and possibly a cardiac ultrasound, Dr. Sinnott says.
If the heart is normal, the brain will be examined by MRI or CAT scan. Your vet might also do more testing to look for underlying disease that could cause a blood clot, such as hormone testing, bloodwork, and urinalysis, she says.
Once the cause is determined, treatment will aim to resolve it, Dr. Levitzke says. If a clot caused the stroke, blood thinners might be prescribed, or high blood pressure medications might be in order for a stroke caused by hypertension.
“The neurologic signs associated with a stroke are allowed to resolve on their own as the patient’s body re-establishes blood flow to the affected area and swelling resolves. Medications such as steroids, mannitol and hypertonic saline can help resolve swelling in the brain,” Dr. Levitzke says.
Managing urination and defecation, maintaining good nutrition, and simple physical therapy (massage, passive range of motion of limbs, if needed, etc.) are important for healing. “The brain is very adept at recovery, though it can take time,” says Dr. Levitzke.
Can Strokes in Dogs be Prevented?
Strokes per se cannot be prevented. However, given the fact that they are associated with underlying disease processes, routine check-ups with a veterinarian and screening blood work can identify potential causes that can be addressed, says Dr. Levitzke.