Are My Dog's Heart Failure and Seizures Linked?

When a dog has more than one set of symptoms it’s easy to try and explain everything with a single disease. Unfortunately, biology can be a bit more complicated than that!

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Hi, I've watched your videos on dog seizures and found them very useful. My dog has recently been having them daily (most often in the evening/night while she is resting). She is a mixed breed rescue who is between 14-16 years of age and is very active and happy at other times. Her blood and urine tests don't show anything abnormal but she does have a very bad heart (enlarged, irregular pulse) and is on pimobendan/Vetmedin and frusemide/Lasix. It's possible that she's been having them occasionally for 2 years but it was misdiagnosed as her losing consciousness due to heart disease. If so, it has increased in severity where it is easier to identify as a seizure. My question is: Is heart disease a possible other cause of seizures?

Right, so moving onto my next question, and that's from Lasanthi who's dog has heart failure and has recently developed seizures. Is there a link?

What does a seizure look like

So I’ll start off by saying that seizure activity typically involves a loss of consciousness along with what we call tonic-clonic muscle contractions. So that's where we have the typical seizure activity where their legs, and their other muscles, contract and then relax, or they contract in an alternating way.

This then causes the legs to start extending and then contracting, extending and contracting and we get the tremors and rigidity that we would typically associate with having fits.

What about collapsing?

Now collapse due to heart failure can take place with or without loss of consciousness. So if a dog’s not getting loss of consciousness, then we're going to know that that's a collapsing episode and that's not a seizure.

If we do get loss of consciousness though, we don't get that muscle activity that we do with seizures. So we often get a weakness first. They'll get wobbly on their legs and then fall to the ground. Now, if they do lose consciousness, then like I said, they don't contract and relax their muscles or they don't become rigid, like a typical seizure.

Instead, the opposite happens, with collapse due to heart failure would cause the muscles to become limp.

A video can help

So there is a difference between collapsing and having seizures. It's important that we appreciate that difference and again that kind of goes back to taking a video of an episode while your pet is having it so that we can be certain that we're dealing with the right thing.

Because, if we're actually dealing with a dog who is collapsing and not having seizures then there's a whole load of things we potentially don't need to do, especially in a dog that has already been diagnosed with heart disease. We've got our diagnosis already, whereas seizures are caused by different things.

So, the bottom line here is that we're not going to get seizure activity due to heart disease in this dog.

Causes of seizures

So causes of seizures in dogs can really be broken down into a number of different groups if you'd like. Toxins is one. That's something that a dog has eaten such as a poison, slug bait or mycotoxin, which is from moldy food. There's a whole range of different things that can cause seizures. Infection, for example, so things like meningitis or other infections can cause seizures. We can get organ disease or hormonal abnormalities that causes changes in the blood that then can trigger seizures. We can get central lesions, so that's lesions within the brain that can cause seizures. So that can be kind of brain masses, brain tumors and that kind of thing, and we can also get epilepsy.

So depending on the age of the dog, the nature of the seizures and the clinical exam in between seizures depends on what's going to be more likely.

Now epilepsy isn't going to be likely in this case because that's a disease of young dogs. It typically starts between about one to five years of age, there’s a little bit of variation there but it's a disease that starts in early age. Poisons are always a potential, but that's really going to most likely cause one off seizures. Infections, that can happen at any age. There are some that are more likely to affect different aged dogs.

Organ disease is definitely something the older dogs can be affected with, but you tend to get changes in between seizures. So you might see vomiting, diarrhea, changes in drinking and urination, that kind of thing. And then central lesions, so like brain tumors and again we would often see other neurological changes in between kind of that seizure activity but that can be sometimes very difficult to appreciate.

So really those are the causes of seizures and I wouldn't expect the heart failure to be related, but taking a video is going to be a good idea so that you can really confirm that it is seizure activity and not just a collapse with loss of consciousness.

The above is a transcript taken from “The Dr Alex Answers Show”.

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