One of the more common emergency conditions we deal with is seizures. Seizures can occur for a number of reasons and at any age, from the young puppy or kitten to the elderly patient. The reasons for seizures can be as diverse as the patients. It can be a very traumatic event for both you and your pet when it first occurs, so being informed can help you to provide the best care for your mate and hopefully be a little less distressed if a seizure occurs.
I recently saw a young dog who had seizured so much that he was not able to respond to us. He had been fine the previous day but found seizuring in the morning. There was no known access to toxins and other tests did not reveal any specific causes, but unfortunately, his owner decided not to continue with his care before more investigation could be performed.
All seizures are essentially caused by abnormal signals in the brain, however, the origin of seizure disorders will be classified as intracranial (within the brain or central nervous system) or extracranial (outside of the brain). Intracranial diseases include such disorders as brain tumours, meningitis or other inflammatory conditions and commonly, canine epilepsy. Seizures can develop as a result of scarring of brain tissue from earlier head trauma, or migration of parasites into the brain tissues. Infections of the central nervous system from bacteria, fungal infections and viruses can also result in seizures.
Extracranial causes of seizures can be just as diverse, often resulting from organ dysfunction, commonly of the liver. The liver metabolises and clears all the nasty toxins from the body. If it is not working properly, it is unable to do this job successfully resulting in a build up of toxins that can overload the brain and result in seizures.
A common cause of seizures, particularly in the very young patients, is low blood glucose levels. Glucose levels drop quickly in puppies and kittens who are either unwell or not eating for various reasons. Brain cells are unable to function properly in a low glucose environment, leading to abnormalities in nerve conduction. Adult patients who have blood-borne bacterial infections or who receive an insulin overdose may also seizure due to low blood glucose levels. There is a also a type of cancer in the pancreas, called an insulinoma, in which insulin is produced excessively, often resulting in severe drops in blood glucose levels.
Low blood calcium levels also commonly cause seizures as calcium is also very important for nerve conduction in the brain. Eclampsia or “milk fever” is a common name for the condition where lactating bitches begin to tremor and seizure in the days or weeks after giving birth, especially to large litters. This is due to loss of calcium in milk when their diet is lacking in nutritional balance.
Toxins can also be a cause of extra cranial seizures and there are many that should be considered before a diagnosis can be made. Some of the more common toxins include lead, antifreeze, snail baits, organophosphates, strychnine, certain types of garbage ingestion, recreational drugs and toads. Occasionally foul play can be involved, but in general, accidental access in the pet’s yard is the main cause.
Some seizures will be termed “partial” or focal seizures, where the seizure appears to be localized to a part of the animal’s body, such as a facial twitch. Some random behaviours, including “fly-catching”, can be types of seizures. These classifications are due to more localized intracranial causes but can still be forms of epilepsy.
These are just a few of the potential causes of seizures. The most common diagnosis for seizures in our dogs (less so for cats) is epilepsy. However, the underlying message is that if your pet has a seizure, epilepsy is not necessarily the cause, and many other conditions need to be ruled out before epilepsy can be assumed. Even then, there is no diagnostic test that confirms epilepsy.
So, what does a seizure look like? Syncopal (pronounced “Sin-cop-all”) episodes may be confused for seizures. A syncopal episode occurs as a result of heart disease. The animal will generally collapse without significant tremoring or other stressed muscular actions. However, I did recently see a cat who was having syncopal episodes due to a heart problem and kind of looked like she was seizuring. Her actions included stretching and curling, she was unresponsive to us, but when she came to, she appeared normal. Most animals will remain mentally inappropriate after their seizure for a short period, known as the “post-ictal” period.
A seizure can be a very violent action. It often involves a loss of awareness, possibly followed by twitching, drooling, sometimes jaw champing before falling and either showing rigid limbs or violent paddling. Some will stretch open their jaw as though howling. Loss of bowel and bladder control is common. After what seems like an eternity the animal may relax, though it will be a little longer before they come to and then they may not be mentally appropriate. The post-ictal period may see some animals become very excitable and some will pace or vocalise.
During a seizure, the best thing you can do as an owner is not to panic and make sure your pet is in a safe position, unable to hurt themselves by falling objects or falling from heights. It is extremely rare for an animal to swallow their tongue and placing your hand in their mouth is more likely to get you bitten and injured than serving any benefit to your pet. Most seizures will only last around 30-60 seconds, though seem like an eternity. In some cases, the animal continues to seizure (what we term “status epilepticus”). This scenario is a true emergency and you need to contact your vet immediately! Continued seizures lead to overheating and potentially fatal injury to the blood and internal organs.
The diagnostic process for seizures can be lengthy and “unrewarding”. I say this because of the perceived lack of value of performing tests which do not reveal any diagnosis. In the opinion of the veterinarian though, a negative diagnostic test can be just as informative for what you are not finding, hence, ruling out potential conditions. I have met many owners who felt that their vet has wasted their money on blood tests or x-rays that have come back normal. But if those tests were not performed and an obvious cause was there….
A thorough history is the first important step in any diagnostic work up. Further diagnosis may require a thorough blood work up, looking at organ functions and blood cells, examination of the urine, blood titres for certain microorganisms, spinal fluid analysis, and brain imaging with CT scans and/or MRIs where available. Where finances are limiting, sometimes a treatment trial with anti-epileptic medication will be performed depending on what the vet thinks the underlying cause may be. There is little point, for example, in trialling anti-seizure medications if the cause is a liver shunt or snail bait intoxication. When commencing anti-epileptic medication, most animals will be lethargic and a little sedated for the first week or two as they learn to adapt to the medication.
Animals can live well with epilepsy for a reasonable length of time if their seizures are adequately controlled on medications. If not, additional medications may be required, or further diagnostics where they were not performed initially. Seizures can be quite harrowing for owners and their pets, so it is important to get to the bottom of the condition early and gain appropriate supportive care.