The Heart of the Matter

Do dogs have strokes?

Yes. A stroke, or cerebrovascular accident, is the term used for the signs shown by a dog when the blood supply to the brain is reduced. There are two types of stroke: An ischemic stroke is caused by a sudden lack of blood supply to the brain. A hemorrhagic stroke is when bleeding occurs within the brain after a blood vessel ruptures.

The brain requires a constant supply of blood to provide it with oxygen and nutrients and then remove waste products. Ischemia is the term for interruption or severe reduction of the blood supply to the brain. In these cases, brain function is critically affected. An infarct refers to when the blood supply is cut off to a specific region of the brain fed by the affected artery. The brain cells in this part of the brain are destroyed.

The diseases causing an ischemic stroke can be basically divided into those diseases causing narrowing of an artery(thrombosis) and diseases causing clogging of the 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 pooling of blood in between the brain and the skull (subdural or subarachnoid hemorrhage). The site of the bleeding depends on the location of the affected blood vessel.

What are the signs when a dog has had a stroke?

The signs of strokes in dogs include tilting or turning of the head, loss of balance, loss of vision, circling or falling. These signs are not specific for stroke and may be symptoms of other diseases of the brain.

In order to make a definite diagnosis of stroke, it is necessary to take a picture of the brain using magnetic resonance imaging, otherwise known as an MRI. A spinal tap is also performed to remove spinal fluid, which will be tested to check for other potential diseases that could cause similar signs. It is not possible to make this diagnosis using standard X-rays.

Other diseases that could mimic a stroke include inflammation or infection of the brain, bleeding from a brain tumor, or a metastatic tumor that is spreading to the brain. Once the dog has been diagnosed with a stroke, further testing will be needed to determine the underlying cause.

Ischemic strokes have been associated with many medical conditions in dogs. These include kidney disease, heart disease, under- and over-active thyroid glands, Cushing’s disease, diabetes and high blood pressure (hypertension). Other less common causes of a blockage of the blood vessels supplying the brain include clogging by a fragment of tumor, fat, parasites or spinal cartilage. In most cases, it is difficult to determine the underlying cause, despite thorough investigation and advanced imaging.

Hemorrhagic strokes in dogs can be seen with diseases that interfere with blood clotting, some rodent poisons, immune-mediated thrombocytopenia (platelet disorder), congenital clotting diseases, diseases that cause high blood pressure (kidney, heart, Cushing’s or thyroid disease), inflammation of the arteries (vasculitis), or abnormal development of blood vessels in the brain. Head trauma, bleeding from a brain tumor or from a tumor spreading to the brain (especially common with tumors of the spleen) are other causes of bleeding in the brain.

Is there treatment for a 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 the potential cause for the stroke, and if a cause is found, treating it to prevent further strokes. Good supportive care is essential for recovery.

Although there is no specific treatment for strokes in dogs, in cases of mild to moderate strokes, most dogs tend to recover within a few weeks. However, recovery may not be possible if the stroke has destroyed a vital part of the brain. The long-term prognosis and chances of another stroke depend on the cause of the stroke and whether this can be successfully treated.

Do dogs have heart attacks?

In humans, a heart attack usually refers to a myocardial infarction. This is when the cells die in an area of the heart muscle, also known as the myocardium. Cell death is usually due to oxygen deprivation caused by the obstruction of the coronary blood vessels that supply blood to the heart muscle. Heart attacks are rare in dogs, but sudden and unexpected death in dogs diagnosed with any form of heart disease is possible.

There are two categories of heart disease in dogs. The first is congenital, meaning the dog is born with the condition, and the second type is acquired, which is a disease that develops later in life. The majority of cases, roughly 95 percent, are considered to be acquired.

Congenital conditions can be inherited from the sire and dam or the result of the breed’s predisposition. Congestive heart failure, dilated cardiomyopathy and pulmonic stenosis are the most common types of congenital heart disease in canines.

Congestive heart failure occurs when the dog’s heart has trouble pumping the proper amount of blood throughout the body. There is then an increase in fluid and pressure within the heart, which can leak into the lungs and make it harder for the dog to breathe. This condition can affect both sides of the heart and may take years to become noticeable.

Canine dilated cardiomyopathy is a disease that affects the cardiac muscles and reduces the heart’s ability to produce enough pressure to pump blood throughout the vascular system. Studies show this condition is most often genetic, but it can also be caused by factors relating to nutrition and infection.

Pulmonary stenosis is a heart defect that consists of a malformation of the pulmonic (lung) valve in the heart. The faulty valve severely restricts the blood flow from the heart into the lungs. This inherited, genetic defect may be associated with other congenital defects of the heart.

Acquired conditions are most often seen in middle-aged and older dogs. These conditions typically develop over time and are the result of normal wear, tear and aging.

Valvular disease occurs when the heart valves weaken and begin to leak. The sloshing of blood through the leaky valves can be heard with a stethoscope as a heart murmur.

Arrhythmias occur when a problem develops within the dog’s electrical system and interferes with the sequence of how the heart should beat. Pericardial disease is the name for the condition where the sac that surrounds the heart fills with fluid or blood. As the pressure of the fluid in the sac increases, the heart is unable to beat normally.

What are the signs of heart disease in dogs?

There are several key signs to be aware of that signal the onset of heart disease in your dog. A dry, non-productive cough that follows exercise or gets worse at night indicates fluid build-up in the lungs. This may be accompanied by shortness of breath and rapid, shallow breathing.

If your dog tires easily, but has trouble sleeping, he may be in the early stages of heart disease. The increased respiratory effort is exhausting, and you may notice a rapid weight loss due to the increased physical activity.

In the later stages of cardiac disease, fluid accumulates in the abdomen, giving the dog a pot-belly appearance. Fainting spells are brought on by overexertion of the poorly functioning heart.

It may take a long time for symptoms of heart disease in dogs to develop. Annual veterinary checkups are important in order to catch these conditions early, when they will have a better response to treatment.