Seizures

A first seizure cannot be sorted into a harmless or a serious cause at home. Poisoning, low blood sugar, bleeding inside the skull and brain inflammation can all first show as a single seizure, and several of these can produce further seizures within hours. The circumstances around the event, including any access to slug pellets, mouse baits, dog flea products in a cat, human medicines, chocolate or xylitol-sweetened foods, often carry much of the diagnostic information. The animal's age, breed, health history, and the specific character of the seizure all contribute to understanding what the event may represent.

Seizures that increase in frequency, duration, or intensity over time may suggest a progressive underlying process. In an animal with an established seizure pattern, a change such as more frequent episodes, longer recovery periods, or the development of new seizure types can be particularly significant, as it may reflect that progression or a change in how well seizures are controlled.

Cluster seizures, where two or more seizures occur within a 24-hour period, represent a different clinical situation from isolated events separated by weeks or months. Clusters can run on into continuous seizure activity, and whether a cluster is settling or building cannot be judged reliably at home.

Seizures that are accompanied by neurological abnormalities between episodes, such as behaviour changes, vision deficits, circling, head tilting, or altered consciousness, may suggest structural brain disease rather than idiopathic epilepsy. The presence of inter-ictal neurological signs can be an important distinguishing factor.

A seizure occurring in an older animal that has not previously had seizure activity may carry different implications compared with new-onset seizures in a young adult. The age of onset influences the range of likely underlying causes and may guide the investigative approach.

A seizure lasting longer than about five minutes, or seizures following one another without the animal regaining normal awareness in between, is known as status epilepticus. Continuous seizure activity drives body temperature up, deprives the brain of oxygen and can cause lasting brain injury or death, with the risk rising the longer it continues. Once established it is less likely to stop on its own, and control generally depends on anticonvulsant medication given by injection, or by the rectal or nasal route in animals already prescribed it for home use.

Seizures in a diabetic animal receiving insulin, in a very young toy-breed puppy, or in a bitch nursing a litter in the weeks after whelping fit the pattern of low blood sugar or low blood calcium. Both can worsen over a short period. Both usually reverse when corrected promptly, although prolonged, severe low blood sugar can leave lasting brain damage.

Some episodes resemble seizures but have other causes. Fainting (syncope) from a heart rhythm problem or heart disease tends to occur during exercise or excitement, lasts seconds, and the animal usually goes limp and returns to normal within a minute or so, without the prolonged confusion, pacing or apparent blindness that often follows a seizure. Some fainting episodes include brief stiffening, so the two cannot always be separated even on video, and heart-related collapse carries its own risk of sudden death. Head tremors in which the dog stays alert and can be distracted, and twitching or paddling during deep sleep that stops when the animal wakes, are more benign patterns.