How can I tell whether it was a seizure or fainting?
Look at three things: what the body was like (floppy or stiff), how long it lasted and how your dog recovered. Fainting often happens during exercise or excitement, lasts a few seconds, the body collapses limp, and the dog gets up quickly as if nothing had happened. An epileptic seizure often happens at rest or during sleep, the body goes stiff or jerks, and there may be drooling, chewing movements or loss of urine. Afterwards the dog is confused and unsteady on its feet, and sometimes does not recognise you for a few minutes or longer.
No single sign is reliable on its own. The 2017 review in Veterinary Evidence shows that fainting can involve brief jerks, and that loss of urine and drooling can occur in both.
What other episodes can look like an epileptic seizure?
Besides fainting, the international IVETF consensus on diagnosing epilepsy lists several episodic disorders that are often mistaken for seizures:
- Vestibular episode: a disturbance of balance, with a head tilt, eyes flicking rhythmically (nystagmus), an unsteady gait and falling to one side.
- Narcolepsy and cataplexy: the dog collapses limp, usually when excited or at mealtimes. In cataplexy it stays conscious; in narcolepsy it suddenly falls asleep.
- Paroxysmal dyskinesia: involuntary movements, cramping or odd postures while the dog is awake and conscious. It is seen mainly in young dogs of certain breeds.
- Pain: sudden spasms of the neck muscles, most often caused by a slipped disc in the neck, can look like twitching, but the dog stays conscious.
Comparison table: seizure, fainting and other episodes
| Episode | Consciousness | Duration | Muscle tone | After the episode | Triggers |
|---|---|---|---|---|---|
| Epileptic seizure | Often impaired | Seconds to minutes; over 5 minutes means status epilepticus | Usually increased: stiff or jerking | Often confusion, unsteadiness, restlessness, hunger, thirst, sleepiness, sometimes temporary blindness | Usually none; sometimes stress, flashing lights |
| Fainting (syncope) | Reduced to absent | Seconds | Floppy, whole body | Usually nothing, quick recovery | Exercise, excitement, coughing |
| Vestibular episode | Normal or disorientated | Seconds to hours | Reduced on one side | Subtle signs of imbalance may remain | Usually none |
| Narcolepsy / cataplexy | Normal in cataplexy, asleep in narcolepsy | Seconds to minutes | Floppy, whole body | Nothing | Excitement, food |
| Paroxysmal dyskinesia | Normal | Seconds to hours | Increased, in one area or throughout | Nothing, or tiredness | None, or activity, exercise, excitement, stress |
| Pain spasms (neck) | Normal | Short, sudden contractions | Contractions of the neck muscles | No confusion; neck pain may persist | Often linked to neck pain |
Source for rows 1-5: the IVETF consensus on diagnosing epilepsy (De Risio et al., 2015). Row 6: the study of 113 dogs with neck spasms (Martinez et al., 2025), in which 62% had neck pain at the consultation and the most common cause was a slipped disc.
Why does a video matter so much?
Because the vet almost never sees the episode in the consulting room, and between episodes the dog can be completely normal. The IVETF consensus recommends that owners record a video whenever possible, along with a detailed history. Even so, a study cited in the same consensus found that vets, neurologists included, agreed with each other only poorly when classifying episodes from video alone. A video does not replace an examination, but it makes it much more accurate.
You can send the videos and the history before the visit, by e-mail, to helga@demed.ro.
What should I watch for so I can describe the episode?
The answers to a few simple questions can make the difference between a quick diagnosis and months of uncertainty. Write them down while your memory is still clear, ideally the same day:
- Before: what your dog was doing (running, playing, sleeping, eating, coughing), and whether in the minutes or hours beforehand it was restless, wanted to be closer to you or went off to hide.
- During the episode: did it respond to its name or to touch, was its body floppy or rigid, were the movements in the whole body or only on one side, was it drooling or chewing on nothing, did it pass urine.
- Duration: timed, not estimated. Start the stopwatch on your phone as soon as you notice the episode.
- After: did it get up straight away as if nothing had happened, or was it confused, unsteady on its feet, very hungry or thirsty, and how long did it take to recover fully.
The same questions appear in the standardised questionnaire that the IVETF consensus recommends for every dog with suspicious episodes.
Can fainting be a heart problem?
Yes, and that is the main reason the difference matters. Fainting happens when the brain gets too little blood for a few seconds, for example because of a heart rhythm disorder (the heart beats too slowly or too fast) or a structural heart disease. The treatment is completely different from that of epilepsy: an antiepileptic drug will not help a dog that faints because of its heart.
If the episode looks like fainting, especially during exercise, or if the vet hears a murmur or an irregular rhythm, the dog needs to be assessed by a vet experienced in cardiology: an electrocardiogram (ECG), 24-hour Holter monitoring and a heart scan (echocardiogram). A neurologist can point you in that direction when the signs suggest the heart.
When is a neurological consultation needed?
When the episodes keep happening, when they are not clearly linked to exercise, when your dog is confused afterwards, or when you are not sure what you saw. The neurological examination shows whether there is a problem with the nervous system and where it is, and an EEG (a recording of the brain’s electrical activity) can help in cases that are hard to tell apart. You will find out how this works on the pages about the neurological consultation and the EEG.
A neurological consultation tells you where the problem comes from and what to do next.
If the episode did turn out to be an epileptic seizure, read about what the different types of epileptic seizures mean.
Frequently asked questions
Can a dog wet or soil itself while fainting?
Yes, it can happen during fainting too, although it is described more often in epileptic seizures. That is why loss of urine on its own does not settle the diagnosis.
Can fainting involve twitching?
Yes. When the brain goes without enough blood for a few seconds, brief jerks or stiffening can occur that look like a seizure. A quick recovery without confusion remains the main clue that it was fainting.
What tests are done to tell fainting from a seizure?
Besides the clinical and neurological examination, your dog may need blood tests, an electrocardiogram (ECG), Holter monitoring, a heart scan (echocardiogram), brain imaging or an EEG. The vet chooses the tests based on the history and on what the video shows.
Sources
- De Risio L. et al. 2015, International veterinary epilepsy task force consensus proposal: diagnostic approach to epilepsy in dogs, BMC Veterinary Research 11:148 (Table 1, episodic disorders)
- Charalambous M. et al. 2017, Epileptic Seizures Versus Syncope: Pathophysiology and Clinical Approach, Veterinary Evidence 2(1)
- Cerda-Gonzalez S. et al. 2021, International Veterinary Canine Dyskinesia Task Force ECVN consensus statement: terminology and classification, Journal of Veterinary Internal Medicine 35:1218-1230
- Martinez A. et al. 2025, Evaluation of Cervical Myoclonus in Dogs with Spinal Diseases: 113 Cases (2014-2023), Animals 15:2298
- Berendt M. et al. 2015, International veterinary epilepsy task force consensus report on epilepsy definition, classification and terminology in companion animals, BMC Veterinary Research 11:182
This article is for information only and does not replace a veterinary consultation.