Myoclonic Seizures in Canines

Canine myoclonic seizures cause sudden jerking motions in your dog’s muscle groups similar to what would occur if your pet received a strong electric shock. These types of canine seizures are often caused by Lafora disease, a degenerative neurological condition.

Myoclonic seizures are not the most common type of seizure found in dogs. In canines, seizures are more likely to be generalized tonic-clonic variety, which used to be known as grand mal seizures. Both myoclonic and tonic-clonic seizures are categorized as primary generalized meaning they involve the left and right brain hemispheres.

The primary difference between the two types is speed of seizure onset. In tonic-clonic seizures, the dog goes through two phases. First, he usually loses consciousness and control over basic body functions, such as the excretory system. Second, his body begins jerking rhythmically for several minutes. In myoclonic seizures, however, the onset of the seizure is faster because the dog does not go through the first phase. Instead, his body begins exhibiting brief jerking motions that can involve specific muscle groups or larger areas of the body.

These types of seizures are usually triggered by quick movements, flashing lights, and/or loud sounds, particularly near the dog’s head. Television, for instance, can sometimes cause a dog to experience a myoclonic seizure.

If the seizures continue to occur over a period of time, they could be a symptom of a genetic, neurological condition called Lafora disease, which is rarely seen among dogs in North America. In 2009, researchers published a case study in the Canadian Veterinary Journal of an 8-year-old male miniature wirehaired dachshund who had been experiencing increasingly severe facial twitches over a four-month period. These twitches were triggered by visual stimulation. Although the researchers could see the seizure activity in the dog’s brain, they used genetic testing to diagnose the cause of the ongoing seizures as Lafora disease.

Lafora disease typically begins affecting dogs after age 5, although the genetic mutation that causes the disease is present at birth. The disease cases progressively worsening myoclonic seizures. Affected dogs also may experience tonic-clonic seizures as the disease progresses. Eventually, affected dogs may lose bodily control, experience dementia, and/or go blind.

Although any dog breed can be affected by Lafora disease, the gene mutation responsible for the disease has been identified in the basset hound and the miniature wirehaired dachshund. A more severe form of the disease is found in beagles.

If your dog’s myoclonic seizures occur infrequently and do not worsen, your veterinarian may not recommend any treatment. Anti-epileptic medications can be prescribed, but they may cause serious side effects, such as liver failure and rear limb weakness. In some cases, the seizures may be resistant to these drugs. Beagles with Lafora disease, for example, are more likely to have drug resistant seizures than other breeds. Furthermore, as the disease progresses the seizures become increasingly resistant.

No cure for the disease is available. Feeding affected dogs a diet low in carbohydrates and high in antioxidants may slow the progression of the disease, but no large scale studies have been conducted to confirm this connection. When the disease progresses enough to interfere with the dog’s qualify of life, your veterinarian most likely will recommend euthanasia.