Seizures in Dogs

Watching your dog have a fit is alarming for any pet parent. But what many people don’t realize is that seizures in dogs are a symptom, rather than a diagnosis in itself.

To control seizures in dogs it’s important to get your dog checked by a vet to search for the cause. For some dogs this means their seizures stop when the underlying health problem is diagnosed and treated. However, for many dogs no cause is found, in which case they have ‘idiopathic seizures’, also known as epilepsy, and anticonvulsant therapy is required.

 

To better understand what your dog’s seizure could mean, here is an overview of the commonest causes of seizures in dogs along with those breeds most likely to be affected.

Toxicities that Cause Seizures in Dogs

Have you ever drunk too much coffee and got the shakes as a result? That pounding heart and shaking hand is down to the stimulant effects of caffeine. Actually, taken to excess caffeine can causes seizures.

Our pet pals are more sensitive to common substances such as caffeine and theobromine found in coffee, tea, and chocolate; which is why so many food stuffs are off the menu for dogs. Other examples include low-sugar products (xylitol is a complete no-no) and alcohol.

It’s all a matter of dose! Many common medications can trigger seizures in dogs, due to sensitivity or overdose. Just think how much smaller a dog is compared to a person and you begin to see how easily problems happen.

Those medications regularly topping lists of accidental poisonings include:

  • Illicit drugs such as cannabis, synthetic cannaboids, amphetamines, and cocaine
  • Human medications such as ibuprofen, 5-Fu cream, diphenhydramine, and antidepressants such as fluoxetine
  • Overdose of antiparasite treatments such as ivermectin, pyrethrum, selamectin, or pyrethroids
  • Rodenticides such as metaldehyde, strychnine, or bifenthrin

As to which dogs are most at risk, chow hounds such as the Labrador who eat first and never ask questions place themselves in danger by eating what they shouldn’t.

Breeds with a Genetic Tendency to Seizure

Sadly, some dogs are born with a genetic pre-programing which places them at greater risk of seizure. Not all pups in the litter may be affected, but in this case the cause of the fits lie with parentage not poisoning.

Brace yourself for some long names.

  • Pug Encephalitis: This condition is a rare genetic predisposition to brain inflammation, resulting in behavior changes and seizures. Sadly, pug encephalitis has a poor long term outlook However, if your pug has seizures there could be many other explanations, so don’t worry until your vet tells you to. Other breeds such as Chihuahuas, Maltese terriers, and Yorkshire terriers can suffer from a similar type of brain inflammation.
  • Under-developed Brains: Breeds such as the Lhasa Apso, Irish setter, wire-haired fox terriers, and Samoyeds are recognized as suffering from lissencephaly and cerebellar hypoplasia. This is where the brain doesn’t develop properly, resulting in odd behavior and seizures.
  • Water on the Brain: Also known as hydrocephalus, this is where fluid builds up around the brain and squashes it. This is well-recognized in toy breeds, such as the Chihuahua, and squish-faced breeds such as pugs, pekes, and French bulldogs.

Metabolic Causes of Seizures

Metabolism is the process of breaking down and processing food, to supply the body’s need for energy. When something goes wrong, the result is a buildup of naturally occurring toxins which slowly poison the body. The commonest causes are:

  • Disturbances in blood sugar levels: Both very low (hypoglycemia) and very high (hyperglycemia) levels result in neurological abnormalities including seizures.
  • Hepatic Encephalopathy: This affects younger dogs that have a fault with how the liver is plumbed into the circulation. This is a portosystemic shunt (PSS) and results in high levels of blood ammonia, which causes seizures and drooling, especially after eating. Breeds that are over represented with PSS include the Yorkshire terrier, Cairn terrier, Golden retrievers, miniature schnauzers, and Old English sheepdogs.
  • Older dogs: Seniors of any breed with kidney disease or underactive thyroids are at risk of secondary metabolic seizures.

Infections that Cause Seizures in Dogs

It’s also possible to catch an infection that causes seizures.

  • Migratory Parasites: Examples include heartworm (Dilofilaria), lungworm (Angiostrongylus), tapeworm (Taenia species), roundworm (Toxocara species) and hookworm (Ancylostoma.) Larvae traveling through the brain cause inflammation and bleeding, which can result in fits.
  • Bacterial and Viral infections: Of these the classic is the distemper virus which causes seizures as a late stage symptom. Bacterial or viral infections can cause meningitis with serious, sudden onset seizures.
  • Protozoal infections: Single-celled parasites such as Neospora, Toxoplasma, or Isospora can set up home in the brain, causing inflammation that triggers seizures. These are often the result of the dog eating an intermediate host, such as infected mouse, and becoming accidentally infected as a result.

Idiopathic Seizures

Lastly, the most significant group are those dogs suffering idiopathic seizures. Actually, idiopathic is a fancy way of saying no-one knows why the dogs has fits. The most well-known idiopathic seizures is ‘epilepsy’.

True epilepsy is a diagnosis of exclusion. This means all the tests have been done, from blood tests to brain scans, and no abnormalities were found. The conclusion is the fit is a result of abnormal electrical activity in the brain. Some dogs have identifiable triggers such as stress or sleep, whilst for others the seizures strike out of the blue.
Several dog breeds are linked to an increased risk of epilepsy, although a genetic predisposition hasn’t been positively proven.  Because no underlying cause is present that can be treated, many epileptics need to take anti-convulsant medication in order to control their symptoms.

Breeds most linked to epilepsy include:

 

And finally, if your dog has a fit, stay calm.

Keep things quiet by switching off lights and turning off the TV. Check to see if the dog is in danger of hurting themselves on furniture, and if so place a cushion in the way to protect them. Do not attempt to touch or move the dog, unless they are in imminent danger such as falling into a fire or tumbling downstairs. Most fits last a few minutes only, at which point phone the vet for further instructions about what to do next.