Overview of Syncope (Fainting) in Dogs
The term syncope (or fainting) refers to a brief period of unconsciousness due a lack of blood flow or oxygen to the brain. Syncope causes collapse, which may last from seconds to minutes. Most fainting “spells” are due to low blood pressure or lack of oxygen delivery to the brain (cerebral hypoxia). Syncope is a clinical sign, not a diagnosis or primary form of heart disease.
Blood pressure depends mostly on heart and blood vessel function. Accordingly, disorders of the heart or vessels (cardiovascular system) are the most common causes of syncope. Often, the cause is an electrical disturbance of the heart (slow or irregular heart activity). At other times, there is a structural problem of the heart (such as an abnormality of the heart muscle or a valve) or pericardial disease (the sac around the heart). Recurrent syncopal attacks may cause brain injury.
Other conditions that can lead to syncope include: severe respiratory disease or severe coughing; metabolic (body chemistry) disease; endocrine (hormonal) disorders; dysautonomia (abnormal function of the involuntary nervous system); anemia and drug therapy. The brief event ends with rapid and complete recovery, in most cases.
What To Watch For
Diagnosis of Syncope in Dogs
Diagnostic studies should include:
Treatment of Syncope in Dogs
The treatment of syncope must be tailored to the underlying cause. In most cases, syncope is an historical complaint, but the cause of the problem must be sought and managed to prevent further occurrences.
Optimal treatment for a pet with syncope requires a combination of home and professional veterinary care. Follow-up can be critical. Administer prescribed medication(s) as directed, and be certain to alert your veterinarian if you are experiencing problems treating your pet. Exact follow-up depends upon the cause.
Prevention of Syncope in Dogs
In-depth Information on Syncope in Dogs
Syncope (fainting) is a symptom related to a wide number of disorders.
Causes of Syncope in Dogs
Heart conditions that may cause syncope include:
Some heart conditions are especially common in particular breeds, for example:
Syncope (fainting) must be distinguished from brain dysfunction or weakness related to neurologic disease (such as epilepsy), stroke, neuromuscular disease, orthopedic (bone and joint) diseases, and metabolic disorders such as liver failure. Syncope can occur in any breed and in pets of any age.
As there are dozens of reasons for syncope, your veterinarian must formulate an often-detailed evaluation to make a correct diagnosis. The conditions most often confused with syncope are seizure disorders (epileptic fits), metabolic (body chemistry and hormone) diseases, and disorders of muscle, bone and joints (musculoskeletal diseases).
You can assist in the diagnosis by observing and writing down answers to the following questions:
A complete medical history should be obtained and your veterinarian should complete a thorough physical examination with an emphasis on stethoscope examination (auscultation) of the heart and lungs. Medical tests are needed to establish the diagnosis, exclude other diseases, and determine the impact of syncope on your pet. The minimum “database” for syncope varies depending on the duration of signs, presence of systemic signs, and physical examination findings. Recommended tests may include:
Your veterinarian may recommend additional diagnostic tests to insure optimal medical care. These are selected on a case-by-case basis (if indicated from the examination, prior test results, or lack of response). When a syncopal patient does not respond to symptomatic therapy or if a definitive diagnosis has not been attained, other diagnostic tests may be recommended. These tests may include:
The treatment for syncope depends entirely on the underlying cause.