Ask the Vet: Dog Tremors by Frank Utchen, DVM

Dear Bishop Ranch Veterinary Center & Urgent Care,

My dog gets tremors and her whole body shakes. She seems to panic during these episodes, almost running in circles. This may last up to 5 to 10 minutes. She was chewing on Himalayan Yak cheese bones, but we recently stopped. We keep our home warm and Luna has blankets. Any idea what this may be coming from?

-Barbara B.

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Dear Barbara,

First, it will help us if we know a little more about Luna: 1st, what breed is she? 2nd, how old is she? 3rd, approximately how frequently is this happening, and how many times total would you estimate you have seen this? 4th, has this happened since you stopped giving her the cheese bones? 5th, if she is less than a year old, and if you are able to compare her with her littermates, is she about the same size as her littermates, or is she maybe the runt of the litter? And 6th, I just need to be sure Luna is not getting into any chocolate, which itself could cause something like you are seeing.

Without knowing the answers to those questions, and not having examined her, the following must be understood to be a “best guess”:

To begin with one of your concerns, it is unlikely that anything in the chew bones is anything to worry about. Although yak cheese bones might be too hard for a dog’s teeth, and some dogs can crack a tooth/teeth chewing on them (like people chewing on very hard candy),  I can’t find any reports or other information that suggests they could cause anything like you are describing with Luna.  

So here’s my line of thought:

You may be seeing a mild version of an epileptic seizure. This is not a serious problem for Luna based on your description (assuming that is what we are seeing with her), although we understand that the term “epilepsy” can sound alarming. Read on…

Just like people, some dogs can have epilepsy, which means the brain fires off random repeated electrical signals to the body causing muscle contractions to various degrees. This is surprisingly common in dogs and is almost always not harmful to them. (See below for my experience with my own dogs). A seizure can be severe, which would involve collapsing and shaking of the whole body, usually lasting less than a minute, although often followed by 30 - 60 minutes of acting “spacey”, or being unsteady on their feet, or appearing not to see or hear. Those after-effects are referred to as the “post-ictal signs”. It is believed that dogs are unaware of the situation when it is happening, although that is impossible to know with certainty. That conclusion is drawn from the experiences of people who report not remembering having a seizure.

If a dog has seizures like that, and is observed to have them more than 3 or 4 times a year, we will discuss starting medications to attempt to reduce the frequency and severity of the seizures. Treatment is considered successful if a dog is only observed to have 1 or 2 seizures a year. However, those numbers need some context, and if a dog is having a seizure every month or more often (this is not very common), then “success” would likely involve more than 1 or 2 seizures being observed every year.*

Other times, a seizure can be mild, sometimes called a “partial seizure” which might only involve part of the body or be more generalized like you describe, but not especially severe. For example, one of my dogs had partial seizures only involving twitching of facial muscles and jaw chattering, which would last about a minute. This happened 3 or 4 times a year his whole life. We also see dogs who act like you are describing with Luna, that are ultimately diagnosed as having partial seizures.

In my own case, in addition to the dog of mine that I just mentioned, I have had two other dogs in the past 30 years who have had epilepsy to very mild degrees (this is how common epilepsy is in dogs). Those two had full-body seizures, but I only observed a seizure like that once in one of my dogs, and only twice in the lifetime of the last one. Those two dogs both had the typical “post-ictal” signs as I described above. I did not treat any of my dogs and they all lived long healthy lives.

There is one theory, however, that bears considering: put in simple terms, it is believed that in some cases, the more seizures a dog has, the more frequent and possibly more severe they can become. It is as if the brain’s repeated experience of generating a seizure is something that it “learns” to do better and better every time it happens. By that line of thought, it makes sense to start a dog on medications sooner than later, to help avoid the tendency of seizures getting ingrained in the brain. Again, that is theoretical at this point.

Bottom line is that if what we are seeing with Luna is partial/mild epileptic seizures, it would depend how frequently they are occurring in order to decide if we should start her on meds to prevent this from progressing. Really impossible to predict how much this could progress in terms of frequency and severity, or over what time period, although it sounds like the appearance of what you are seeing is mild.

OK, enough about epileptic seizures. We can certainly do more of a deep dive on that if you want to bring her in for a checkup. But I want to leave you with one final thought: rarely we’ll see young dogs – typically less than a year old – who have an under-developed liver due to the lack of a normal amount of blood flow through it. Since the liver cleans the blood of various by-products that can be harmful, if a dog does not have proper blood flow through the liver due to a blood vessel abnormality where some of the blood vessels that should flow into the liver make a detour around the liver instead (called a liver shunt), a dog’s blood can accumulate certain compounds that can affect the normal functioning of the brain. This could could lead to a situation like you are observing or even very severe seizures. The technical term for the resulting neurologic signs that occur is called “Hepatic Encephalopathy”, and the underlying blood vessel abnormality that allows some blood to bypass the liver is called a “Porto-systemic shunt”. This can be diagnosed by doing blood tests and an ultrasound exam, and can be treated surgically by re-routing the blood flow through the liver by permanently clamping off the shunt, thereby forcing the blood to flow through the other (underdeveloped) blood vessels inside the liver. Over time, those underdeveloped blood vessels expand and multiply to accommodate the increased blood flow that has been re-directed through them. 

So that’s a rather long answer to a short question, but without having answers to the 6 questions I posed at the top of this response, those are the two conditions that come to mind immediately for me. Again, like with many Q&A situations, I’m a bit hamstrung not actually having examined Luna, but that’s a reasonable way to interpret what your are seeing with her. 

Please let me know how this continues to go for Luna, and if you have further questions please feel free to ask those as well.

Happy holidays to you and Luna!

Frank Utchen, DVM

* I use the term “observed” seizures, because it is understood that a dog might be having more seizures than we actually see, but since all we can know about is what we observe, that is how we have to evaluate this.