Idiopathic Epilepsy in Cats

Idiopathic epilepsy is a specific term referring to a seizure disorder in cats that has no identifiable cause. Although idiopathic epilepsy is very common in dogs, seizures in cats have a 50:50 chance of having a specific cause found. If your cat has a seizure, it is worthwhile to do everything possible to find a cause for the seizures.

Epilepsy is a condition characterized by recurrent seizures. Approximately 0.5 percent of cats are epileptic. Some cats can have one seizure without ever having a second. The seizures can be generalized or partial.

Partial or focal seizures indicate activation of a limited number or group of neurons. Generalized seizures indicate a synchronous discharge of a large number of neurons in both sides of the brain. The majority of cats (50 to 60 percent) with idiopathic epilepsy have generalized seizures.

Seizures usually appear suddenly and end spontaneously. Seizures can last from seconds to minutes. Generalized seizures that last more than 30 minutes or multiple seizures that occur so rapidly as to prevent complete recovery are considered emergency situations that require immediate intervention as permanent brain damage may occur after this 30 minutes.

Some cats exhibit the following three stages of seizures. However, not all cats have the exact type of seizure stages.

The aura or prodromal stage is the time immediately before the actual seizure, which may last minutes or hours. During this time, your cat may show a slight change in behavior or attitude. In many cats, the seizures begin suddenly without any warning signs.

The ictus is the actual seizure episode in which your cat may become stiff, lose consciousness, fall over and begin paddling, vocalize, gnash the teeth, urinate, defecate, and salivate. This stage can last seconds to minutes and is generally the part of the seizure your veterinarian wants you to time. During this time, your cat is unconscious and is not suffering.

The post-ictal phase immediately follows the ictus and begins as your cat regains consciousness, as evidenced by looking around or focusing on something or someone. Some cats remain lying down in exhaustion or fall into a deep sleep. Some stand up after a few seconds or minutes. They may be disoriented, weak, poorly responsive, blind, deaf and/or anxious. Most cats return to normal within a few minutes although some cats may require days to recover completely.

Several different diseases may cause seizures (convulsions). The term idiopathic epilepsy refers to a seizure disorder the cause of which remains unknown despite a thorough diagnostic evaluation. Treatment and prognosis (outcome) of seizures depend on their underlying cause. The following are the most important causes of seizures in cats:

Structural disorders

Viral or inflammatory disorders

Fungal disease (cryptococcosis)

Toxoplasmosis

Encephalitis

Rabies

Brain abscess

Head trauma

Brain tumor

Cerebral infarct (uncommon)

Vasculitis (inflammation of blood vessel)

Developmental disorders (hydrocephalus)