Syncope in Dogs
Syncope is the clinical term for what is otherwise often described as fainting. This is a medical condition that is characterized as a temporary loss of consciousness and spontaneous recovery.
The most common cause of syncope is a temporary interruption in the brain blood supply leading to impairment in oxygen and nutrient delivery to brain. Another important cause of syncope in dogs is heart disease leading to interruption in the blood supply to the brain. Syncope is more commonly seen in older dogs, especially Cocker spaniels, miniature schnauzers, pugs, dachshunds, boxers, and German shepherds.
Causes
- Heart diseases
- Heart tumor
- Emotional stress
- Excitement
- Low concentration of glucose, calcium, sodium in blood
- Diseases leading to thickening of blood
- Use of certain drugs
Situational syncope may be associated with:
- Cough
- Defecation
- Urination
- Swallowing
- After pulling on the dog’s collar
Diagnosis
Although syncope often only causes temporary loss of consciousness, diagnosing the underlying cause is important for the affected patient, since the underlying condition may be of a chronic and progressive nature, or may even be life-threatening.
Your veterinarian will take your dog's health history and will carry out a detailed physical examination. Routine laboratory tests include complete blood count, biochemistry profile, and urinalysis.
The results of these tests are often within normal ranges, but if hypoglycemia is the cause of syncope, the biochemistry profile will indicate lower than normal levels of glucose in the blood. In these patients, insulin concentration is also measured. Further testing may be required in patients with low sodium or potassium levels in blood. As heart disease remains one of the important causes of syncope, an electrocardiogram (ECG) and echocardiography will be conducted to determine whether there is an underlying heart disease.
Your veterinarian will also ask you to calculate your dog's heart rate during syncopic episodes at home and may recommend 24-hour ECG monitoring if your dog has been determined to have an underlying heart problems. A computed tomography (CT) scan of the head, and an analysis of cerebrospinal fluid (the fluid that bathes the brain and spinal cord) will be conducted if brain disease is suspected.
Treatment
Syncope is a temporary and reversible condition, with the dog regaining consciousness soon after an episode of unconsciousness. However, if the underlying cause is not treated in time, it can lead to recurrent episodes of syncope and aggravation of other symptoms related to the underlying disease.
If side effects due to medication are responsible for the syncopic episodes, your veterinarian will halt the use of the medication. If the medications are necessary for your dog's long term health, your doctor will look into other medications that can be used without the harmful side effects.
Living and Management
Protect your dog from being exposed to the types of stimulus that can provoke an episode of syncope. If cardiac insufficiency is the cause, physical activity should be minimized to prevent further stress on the heart. Moreover, stress and excitement can also contribute to an episode of syncope and should be prevented as much as possible. You will need to take your dog for regular checkups until it has fully recovered.
Watch your dog closely at home for another episode of fainting and call your veterinarian immediately if the dog begins to show symptoms of losing consciousness again. The usual prognosis for patients with heart disease related to syncope is not good. However, for patients that do not have a non-cardiac related condition underlying the syncope, the overall prognosis is good, especially if the primary disease is treated.