Seizures In Older Dogs
Seizures in older animals are relatively common and can exhibit in different forms depending on the underlying cause and/or location of the lesion within the brain. However, there are also causes of seizures related to abnormalities not associated directly with the brain. There can be toxins within the body (a liver shunt, kidney disease), or ingested toxins (snail bait, medications, alcohol and many others). A low blood sugar (glucose) can also result in seizures.
There are several different types of seizures: Grand Mal, Focal (Partial Motor or Petit Mal) and Psychomotor). Grand Mal seizures are the most prevalent, and seeing your pet having one can be frightening. In this type of seizure the animal usually falls on its side, the head draws back on the body, the legs move uncontrollably and there may be vocalization in the form of whining, crying, moaning, and even, barking. Vocalization is often thought of as pain, but not in this case, it is a reflex from the brain. In most cases urine and/or stool will be expelled. The length of time for the seizure can be extremely variable lasting seconds to minutes. For someone watching it can seem like an eternity and the usual response is to try to comfort the pet to no avail. It is actually best to let the animal finish the seizure without interference. Occasionally the animal will bite the tongue, and there can be significant blood visualized which contributes to the angst. Do not try to prevent this, as severe bite wounds can result to your fingers and hands. In most cases the seizure will end, but the animal will seem disoriented and may not be able to stand or move normally. This is termed the post-ictal phase and can last minutes to hours. The entire process can be emotionally devastating to the pet caregiver, but it’s important to know that the creature is completely unaware of the seizure and there is no pain associated with it.
If the seizure does not stop or if clusters of seizures occur in a short period of time, this constitutes an emergency and the animal needs to be taken to a veterinary hospital, preferably a 24 hour or specialty hospital, as soon as possible. Accomplishing this may be extremely difficult if the seizure is ongoing. A small dog or cat can be wrapped in a blanket or towel or placed in a carrier. A larger dog can be wrapped in a large blanket and carried to and placed in a vehicle for transport. Fortunately, the animal will not be aware which can make it somewhat easier. Unfortunately, getting the animal into a vehicle when they are in status epilepticus (as the constant seizure state is called) can be nearly impossible. A phone call to the destination hospital informing them of what’s going on would be a good idea so they can be ready.
Causes of seizures in the older dog
In general terms the cause of the seizure can usually be related to one of three general groups. First, unknown or idiopathic, second, reactive (due to a metabolic problem or possible ingested toxin), and third, structural (an active pathology or abnormality of the brain such as a tumor or inflammatory process).
Initially it is important to rule out a metabolic imbalance (low blood sugar, electrolyte changes, liver or kidney disease or deficiency of certain vitamins). In most cases a general blood panel will be sufficient for this determination. An ingestion of a toxin can be difficult to diagnose unless the caretaker witnesses their pet doing so. Animals that ingest a toxic substance are usually in a constant seizure state or extremely sensitive to noise or stimulation. Other diagnostic modalities such as radiographs, abdominal ultrasound, MRI’s or CT scans may be necessary to further elucidate the cause of the seizure. However, many of these animals fall into the extreme age category and it may not be prudent to proceed to advanced testing if the routine testing was negative for a cause.
In any patient presenting for recent onset seizure activity it will be important during initial evaluation for the veterinarian to determine if there any signs of reactive or structural brain disease. The answer will help guide decision making regarding further diagnostics and treatment. In senior pets over seven years of age this question becomes increasingly important due to a higher prevalence of intracranial neoplasia within this population. It is important to remember, however, that an equally large portion of the older population can also have idiopathic or primary epilepsy. In fact, studies have reported anywhere between 23-45% of cases of new onset seizures in senior dogs will be diagnosed with primary epilepsy. (Ghormley et al. 2015) Diagnostics therefore are important in these cases to determine the underlying cause and most appropriate treatment. Age may also affect the prevalence of co-morbidities (other diseases), and the degree to which clients are willing to pursue diagnostics, and treatment strategies.
Types of seizures
Grand Mal Seizures:
This is the most common and the scariest seizure seen in dogs and cats. It was described earlier in this missive.
Focal Seizures:
This type of seizure involves involuntary activity in one area of the body. The animal is not aware of what is going on, is not reactive or engaged and does not exhibit symptoms seen with a Grand Mal episode. A rapid movement of the affected body part will be seen. An example would be a chewing gum seizure. This will result in the mouth opening and closing rapidly. This particular type of seizure is often seen with later stages of canine distemper.
Psychomotor Seizures:
These are associated more with a form of abnormal behavior where the animal appears to be in an altered state. The pet may not recognize its owner and may become aggressive. Owners report their animal “spaced out” for a short time, as if it were seeing something that wasn’t there. It may “bite” at the air as if it were chasing a fly.
Seizure versus Fainting
It’s important for pet caretakers to also understand that a seizure is not fainting, which is a condition usually associated with a heart problem and is not neurological in origin, but the result of a lowered oxygen level in the blood. Seizures also result in a period of abnormalcy afterwards that can last a short time or several hours. This post-ictal stage results in the animal being less conscious and appearing disoriented. Fainting usually doesn’t result in disorientation, and the pet is up and acting normally within a few seconds.
Treatments
Phenobarbital:
In my opinion this medication should only be used in the older animal as a last resort, and quite honestly, I don’t recommend it be used at all. It is an inexpensive drug to purchase, but extremely expensive to use because veterinarians require numerous periodic tests to determine if the drug has reached a therapeutic level. Testing needs to be done two weeks after the dose is changed. It is also necessary to test for liver dysfunction, a common sequela of long term use. Only about 30% of animals treated with phenobarbital become seizure free. Also, it can take up to six weeks for the drug to reach a therapeutic level. This period can be shortened by giving a high “loading” dose, which makes the animal barely functional for up to 2 weeks.
Potassium Bromide:
Potassium Bromide is another medication I do not recommend for use in older animals. It is often associated with pancreatitis, which can be devastating for the elderly.
Keppra (Levetiracetam):
Keppra is my first recommendation for dogs that are large enough to use the extended release formulation. The regular formulation has to be given every 7-8 hours or there will be break through seizures in many cases. The Keppra Extended Release appears to be a very safe and well tolerated drug for seizure control. Although, veterinarians will not put small dogs on the extended release version, I have found that small dogs may tolerate the extended release, even though the initial dose may seem quite high. It is important to know that the extended release product cannot be compounded nor can the tablet be split.
Zonisamide:
Zonisamide medication may end up being the best choice. It’s given every 12 hours in the dog, but may only require once daily treatment in the cat. Because it is a sulfa, there is a risk of decreased tear formation resulting in “dry eye” syndrome.
Medical Grade CBD oil:
The FDA has approved a medical grade CBD oil for use in humans with refractory seizures, Epidiolex. There are also numerous reports of CBD oil’s effectiveness in seizure control in animals. That is also my personal recommendation as I have seen it be effective for seizures in older animals and younger ones too. NOTE: Almost all the CBD oil available for animals comes from the hemp plant and is not effective in my view. I recommend VetCBD as it’s from the cannabis plant and quite effective.
Additional thoughts
I often get calls in regard to end of life choices when an older pet has an initial Grand Mal, or other type of seizure. There is a tremendous amount of emotional expense associated when one of these major seizures is visualized. In many cases the animal has not been taken to a veterinarian for an evaluation, and euthanasia is the first thing that seems to enter the pet caretaker’s mind. To me, that is a sad commentary on how the pet public views end of life, and it’s due to how veterinarians approach the elderly animal with a major disease. The greater majority of veterinarians will immediately tell the pet caretaker that their pet likely has a brain tumor. Once that viewpoint has been espoused the pet family will be devastated because that usually means “no hope.” There is always hope in my world as I have seen so many of these little creatures respond to medication, even CBD oil. I never count them out. If the veterinarian rules out a metabolic cause, and the caretaker is amenable to treating the pet, then the animal will often do quite well for a period of time.
https://www.vin.com/veterinarypartner/default.aspx?pid=19239&id=4951440
https://www.medvetforpets.com/approach-to-new-onset-seizures-in-senior-dogs-and-cats/
