Introduction
Seizures are caused by abnormal electrical impulses in the cortex of the brain. These impulses cause a combination of uncontrollable, involuntary and excessive or reduced muscle activities. There are a number of different causes of seizures in domestic dogs. However, the symptoms are fairly classic and easily recognizable.
Symptoms of Seizures in Dogs
Seizures tend to be transient and to start and stop abruptly. Most generalized seizures (also called “grand mal” seizures) start with a period of altered behavior, called the “aura.” During this period, owners may notice one or more of the following signs:
- Far-away look in the eyes
- Agitation
- Nervousness
- Restlessness
- Vocalization
- Unusual clinginess; attention-seeking behavior, or seeking of seclusion
- Confusion
The actual seizure event normally lasts for about two minutes or less and is characterized by one or more of the following symptoms:
- Weakness
- Loss of awareness of the immediate environment
- Trembling
- Collapse
- Rigid extension of the extremities
- Loss of consciousness
- Cessation of breathing (for roughly 10 to 30 seconds)
- Rhythmic jerking or paddling of the legs while lying down (resembles running)
- Muscle twitching (especially facial muscles)
- Teeth chomping; chewing
- Temporary blindness
- Vomiting (emesis)
- Excessive salivation (ptyalism; drooling)
- Inappropriate urination
- Inappropriate defecation
Generalized seizure episodes can last from seconds to minutes. In the time immediately following a seizure (called the post-ictal period), the dog begins to recover. She may still experience temporary blindness, confusion, sleepiness, disorientation and post-seizure convulsions during this period, which typically lasts for about an hour but can last for several days. Dogs with primary epilepsy usually have recurrent seizures that become increasingly frequent over time.
Dogs can also have focal or localized seizures, which only affect a limited part of their bodies. These are usually caused by a brain tumor, brain abscess or other focal brain lesion.
Dogs at Increased Risk
Seizures can occur in dogs of any age, sex or breed. Primary seizures, called epilepsy, are most common in dogs between the ages of 6 months and 5 years. Older dogs tend to suffer seizures caused by brain tumors, while younger dogs are predisposed to seizures from ingestion of toxins, metabolic disorders or conformational abnormalities. Breeds that have been reported to have a genetic predisposition to epilepsy include the Beagle, Belgian Tervuren, Dachshund, Keeshond and German Shepherd. Other breeds with an unusually high incidence of epileptic disorders, but without an established hereditary cause, include the Collie, Cocker Spaniel, Labrador Retriever, Golden Retriever, Irish Setter, Miniature Schnauzer, Siberian Husky, St. Bernard, Poodle and Wire Fox Terrier. Mixed-breed dogs can suffer from seizure disorders, as well.