A seizure is a sudden and uncontrolled burst of activity that may include one or more of the following signs: champing and chewing, foaming at the mouth, collapse, jerking of the legs, and loss of urine and stool. An altered level of consciousness is followed by a gradual return to normal.
Some seizures are atypical. Instead of the classic convulsion, the cat exhibits strange and inappropriate behavior, such as sudden rage or hysteria. Cats may lick and chew themselves, scratch or bite their owner or another cat. This is called a psychomotor seizure.
Toxoplasmosis is a disease caused by the parasite Toxoplasma gondii, which can be found in garden soil and raw meat. Cats can get toxoplasma infection by killing and eating infected prey. The disease can also be passed on from cats to humans.
Most classic seizures in cats are caused by acute poisoning. Seizures after head injury may occur at the time of the accident, but in most cases appear several weeks later as a result of scar tissue on the brain. Stroke, metabolic disorders, and epilepsy are other causes of seizures.
Common poisonings that induce seizures include strychnine, antifreeze (ethylene glycol), lead, insecticides (chlorinated hydrocarbons, organophosphates), and rat poisons. Organophosphates characteristically produce seizures that are preceded by drooling and muscle twitching. A history of exposure to an insecticide (spray, dip, or premise treatment) suggests this diagnosis.
Kidney and liver failure, accompanied by the accumulation of toxins in the blood, can cause seizures and coma.
Epilepsy is a recurrent seizure disorder that originates in the brain. It can be caused by outside influences, such as trauma, which is acquired epilepsy, or from a defect in neurochemicals in the brain, which is idiopathic epilepsy. Idiopathic epilepsy always has symmetrical signs. It is far less common in cats than it is in dogs.
To establish a diagnosis of epilepsy, the attacks must be recurrent and similar. Toward this purpose your veterinarian will ask you to provide a complete description of your cat’s behavior before, during, and after the seizures.
Narcolepsy-cataplexy is a rare condition in which the cat suddenly falls asleep and drops to the ground. The cat may have one or dozens of such attacks in a day, lasting a few seconds or up to 20 minutes. The attacks can be reversed by petting the cat or making a loud noise. The cat is completely normal when awake.