Loss of Consciousness (syncope and coma) in Dogs
Key takeaways
Commonly mistaken for collapse, sleep, and seizure, syncope (or fainting) is a serious condition where dogs lose consciousness briefly, followed by spontaneous recovery.
- A coma may appear to start as a syncopal episode, but refers to the more specific case when unconsciousness is prolonged and dogs cannot be roused
- Any episode of loss of consciousness requires immediate veterinary care to determine the root cause and to initiate treatment
- Loss of consciousness can be caused by many conditions, most commonly cardiac disease, low blood sugar, electrolyte imbalances, and poisoning
- A physical examination, bloodwork, and full cardiac workup are required to diagnose the underlying condition
- Treatment is often supportive in nature and varies based on what caused the episode
- Prognosis for a dog who has experienced loss of consciousness varies greatly based on the underlying cause and can range from favorable to poor
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A closer look: Loss of Consciousness (syncope and coma) in Dogs
Loss of consciousness is rare in dogs, but if it does occur it can be very concerning as it indicates a potential emergency. Any time a dog loses consciousness, they require immediate veterinary care to identify the cause.
Syncope and coma are secondary to a wide variety of conditions, which must be determined in order to proceed with treatment, if required.
Possible causes
There are a large number of conditions and other factors that may cause loss of consciousness in a dog. Essentially any illness that is severe enough to cause shock or imminent death has potential to cause loss of consciousness.
Risk factors
The amount of time a dog is unconscious may vary, as well as the amount of times syncope occurs in a period of time. For example, a dog that is experiencing a choking episode may have a syncopal episode, recover, then have another episode shortly after if the blockage is not cleared. Regarding duration of unconsciousness, a dog that appears to have a syncopal episode but is not awakening may actually be in a coma.
Testing and diagnosis
Diagnosing the root cause of a dog that has experienced loss of consciousness begins with a thorough patient history and physical examination. The events that occurred before, during and after the episode are important in determining the potential cause.
Further diagnostics may include
- Physical examination
- Neurological examination to determine if there are any deficits or brain injuries
- Cardiac workup including auscultation, electrocardiogram (ECG) and diagnostic imaging (X-ray or ultrasound of the heart) to determine if there is any cardiac insufficiency
- Laboratory testing such as bloodwork
Referral to a specialist may be required in some cases.
Treatment relies entirely on what condition caused the episode, and may include:
- Medication (for example, to treat diabetes, heart disease, or thyroid insufficiency)
- Fluid therapy (for rehydration and to correct electrolyte imbalances)
- Detoxification
Occasionally, the cause of an episode cannot be determined. In these cases, close monitoring of the environment and reporting of future episodes is crucial.
Similar symptoms
Associated symptoms
Syncopy is often observed with various other symptoms, depending on the root cause.
