Canine Epilepsy...

...really sucks.

Don't get me wrong, I'm not saying epilepsy is all fun and games for people.  However, canine epilepsy presents some serious challenges.  It is impossible to explain to a dog what is going on; similarly, the dog can't tell you how it's feeling, so it can be hard to recognize the signs pre-seizure.

A number of years ago, MeatHead, the bulldog, was diagnosed with hypothyroid, and then seizures.  
Most beautiful bully ever...
When Meathead was diagnosed, I learned that epilepsy is somewhat common.  The estimate is 4-5%, but anecdotally, many dog owners I know either had or knew someone who had a dog with grand-mal seizures.  There may be breeds predisposed to the disease, but that doesn't yet seem clear.

Epilepsy may be inherited (primary or idiopathic) or acquired (secondary or symptomatic). Seizures resulting from tumor, stroke, metabolic imbalance (think blood sugar, electrolytes) and hypothyroidism would all be considered secondary, because the seizures are the symptom of an underlying disease.  Inherited epilepsy has its own origin, probably genetic, and research is ongoing to try and tease apart the mechanisms of the disease.

What is a seizure, besides scary?  Basically, a seizure is a neurological event.  Think of a normal brain (human or dog) as a net - it's composed of many nerves (segments of rope) that respond to a stimulus (like... a tennis ball hitting the net).  The stimulus is transmitted through the neural network, and is translated into information.  

"Ow, that was hot." or.. "Hey look, a wall."

In a seizure, many different portions of the brain respond improperly to a stimulus.  So instead of a single tennis ball hitting the net, imagine a dozen rapid-fire volleying machines firing at will.  The result is a seizure, either of the grand-mal variety (stiffness, loss of body function, drooling, disorientation, etc) or the focal variety (this may or may not be noticeable, as it involves a smaller portion of the brain).  One seizure event pre-disposes the organism to subsequent seizures.  

Seizures of both types can be preceded by a 'prodrome' stage, and by a 'post-ictal' stage in which the dog lies still or may have trouble getting his bearings.

For a more thorough description of types and stages, go here.  

At the moment, treatment of epilepsy is all about controlling the seizures.  

Because Meatie also has hypothyroid, and hypothyroidism can cause seizures, both conditions must be carefully managed.  The thyroid medication has not resolved the symptoms alone, so he's also been on Potassium Bromide (KBr) for some time.  In the last day, we began supplementing his medication with phenobarbitol (PB).  Both of these drugs decrease the excitability of neurons in the brain.  

Interestingly, PB is not commonly prescribed for humans in developed countries.  Instead, benzodiazepime derivatives like Valium are preferred.  As a barbiturate, dependence, depression, and behavioral changes can result from PB use; however, in developing countries it is still given to humans.  

For dogs, KBr and PB are often given in combination with Diazepam (aka, Valium), one such benzodiazepime derivative.  Diazepam binds to a unique site in a receptor called a GABA receptor, which controls a Chloride 'ion pump' and normally inhibits nerve activity.  This binding makes the GABA receptor more likely to activate (increases the frequency), decreasing excitability.  

Barbiturates like PB bind the GABA receptor as well, but it acts in a different way: binding of PB increases the amount of time the receptor is active (increases efficacy).  PB also binds a receptor called AMPA which typically excites nerves, as well as other receptors in a non-specific manner.  

Side effects of both these drugs include confusion and sedation, which we've seen in our mutt.  PB can cause liver damage over time and requires regular blood testing.

Potassium bromide is a salt, like table salt, but with different elements.  KBr is the only one of these three drugs not approved for use in humans in the USA, because it's difficult to establish an effective dose without causing toxicity (called Bromism).  Bromism can cause changes in appetite, sensory perception, and behavior, aggressiveness, psychoses, and even more seizures.  

Determining a balance of each of these drugs is often necessary to manage canine epilepsy.

What else is a concerned owner to do?  First, we log each of MeatHead's seizures, and talk to the vet when we have concerns.  Like recommendations for people, we keep the area clear.  If he's on the couch or the bed, we move him to the floor.  When he's finished the seizure, we block off the area so he won't tumble down the steps and hurt himself.

There are several alternative therapies out there, but alternative drugs are very expensive because they're typically used in humans (who have insurance).  Administering supplements could make things worse if they cause side effects that haven't been documented by studies.  One thing we do is apply an ice pack to his back when he does have the seizures.  I'm not sure this helps, but at least keeping him cool won't hurt.

Our dog has been on KBr for years, with Diazepam as needed.  Recently, we decided to had PB, since the frequency of seizures has not really decreased to an acceptable level.  Since he's started the PB, Meathead has been disoriented.  The vet said it would take a few days for things to normalize, and I hope it does soon.  It's very hard to watch a loved one (and yes, dogs count) suffer, and it's even harder to be unable to explain it to them.
Mo and MeatHead
For more information, check out the links above.  If you have a story about dogs, canine epilepsy, or anything else, please share in the comments.

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