My Dog Is Fainting - Syncope in Dogs

To talk about syncope in dogs, we need to be clear about its definition. Otherwise known as fainting, syncope is a temporary loss of consciousness, accompanied by a loss of muscle strength. The result means the dog will pass out and fall over. This loss is usually caused by a decrease in oxygen in the brain due to less blood flow. It may be accompanied by muscle twitching.

The key is the loss of consciousness, which is the fundamental symptoms used to identify syncope. While fainting is temporary, it can be of different durations. It is possible for a dog to faint so quickly, they don't even have time to fall over. In other instances, the loss of consciousness can be minutes in duration.

It is important we differentiate fainting from other types of consciousness loss. For example, if a dog goes into toxic shock, they can lose consciousness because their organism is shutting down. This is very dangerous and potentially fatal. Another example is epilepsy in dogs where a dog will have a fit and seemingly lose consciousness.

We can divide the causes of syncope or fainting in dogs into two separate categories, which are the following:

• Cardiovascular origin: fainting can occur due to arrhythmias and various diseases that affect the heart, such as dilated cardiomyopathy or pulmonary stenosis.
• Extracardiac origin: this includes neurological causes such as epilepsy, hemorrhage or encephalitis. Pulmonary causes include pulmonary hypertension, metabolic causes are hypoglycemia, hypocalcemia, hypoadrenocorticism or anemia, and situational causes such as chronic coughing.

Cardiac issues are perhaps the most common cause of syncope in dogs, as well as hypoglycemia. The latter is due to a drop in blood sugar levels. If the dog has arrhythmias, it is worrying as a sudden fainting spell can be due to cardiac arrest. If our dog has been diagnosed with some form of congenital heart disease, congestive heart failure or a heart murmur, we need to be very careful with their health and activity.

Situations of high excitement in dogs can lead to syncope. These could be a fight with another animal, exerting great effort on a walk, exercising too much or performing other activities which raise blood pressure. If a dog has significant heart problems, even minor exertion such as straining when defecating can cause them to faint.

The reason is that greater muscular effort triggers tachycardia. This stimulates the vagal system, decreases heart rate and leads to syncope. This is known as vasovagal syncope in dogs.

Older dogs are often more susceptible to fainting. The reason is that extended life results in wear and tear of the body. Minors efforts become harder to perform. When the heart muscles have also degraded, blood pressure can drop and the dog will faint more easily.

It should be noted that some dogs are more prone to fainting than others. These include brachycephalic dog breeds such as Pugs or Boxer dogs. This is often due to coughing since their morphology restricts airways. Pressure is then increased in the thorax which puts pressure on the heart muscles. The result is a decrease in blood flow and subsequent syncope.

Smaller dog breeds are also more likely to faint than larger dog breeds. Dogs like the Chihuahua and Yorkshire terrier often faint due to hypoglycemia which can occur when they are stressed. This is especially so in puppies of these breeds. Additionally, these breeds are more prone to tracheal collapse. This is an interruption of airflow through the trachea, sometimes leading to syncope.

Before syncope occurs, the dog may show signs of dizziness. If our dog has symptoms such as the following, it means they are likely to faint:

• Sudden and temporary loss of consciousness
• Loss of posture
• Lies on its side
• Legs are stiff
• Emit vocalizations
• Urinates on themselves

Syncope usually lasts for about a minute and the dog shows rapid recovery. For this reason, it is most common to observe the dog faints for only a short number of seconds. If our dog has collapsed, we must contact our veterinarian and describe all the details so they can reach the diagnosis. As stated above, there are other reasons which can cause a dog to lose consciousness, some of them life threatening.

It is important that we look at the dog's behavior before and after the episode. We must also inform the veterinarian if our dog suffers from any disease or is taking any treatment. The vet's exam will focus on exploring the cardiac, respiratory and neurological systems. Blood and urine tests for dogs are performed to detect endocrine or metabolic causes of syncope.

We have already explained that there are multiple causes behind a syncope and that it is not itself a disease, but a symptom. Even if they have only experienced one episode, we should take them to the veterinarian to determine the underlying cause. If it is caused by situational triggers, such as exercise, stress, excitement, fear, pain, etc., we should avoid them as much as possible. For cases involving disease, the vet will have to establish the appropriate treatment and medication.

To detect the cause and treat fainting in dogs, tests such as an electrocardiogram, blood pressure measurement, ultrasound, etc. will be necessary. The dog may require blood pressure medication and the symptoms will need to be managed for the remainder of their life.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to My Dog Is Fainting - Syncope in Dogs, we recommend you visit our First aid category.