16 Seizures – an introduction
Seizures originate from the brain. They are the physical manifestation of abnormal synchronous electrical discharge in the brain. The brain can be stimulated to do so by intracranial or extracranial causes. The chief purpose of clinical examination and laboratory tests is to differentiate the two.
Generalized tonic-clonic seizures were regarded as the most common seizure type but a recent study found 65% of dogs had partial seizures. The difference in opinion is due to recognizing that the commencement of a generalized seizure may have a partial onset, and classifying it as such. Partial seizures may be missed in cats as the motor/behaviour signs can be subtle: sitting, staring, growling, salivating or facial twitching.
A bystander can assess the animal’s mental responsiveness to stimuli but not the level of awareness. This makes it difficult to classify some stereotypic activities as seizures or psychological disturbances. If an animal will not respond to being called or stroked because it is fearful, painful, or struggling to maintain balance, the event may be mistaken for seizure activity and treated inappropriately.