Those who own a pet that has suffered from seizures know firsthand how scary these episodes can be. A seizure is defined as uncontrollable behavior or muscle activity caused by an abnormal increase in the brain’s nervous activities. Epilepsy is a term used to describe recur- ring seizures.
Seizural activity in cats can be quite obvious or quite subtle. In essence, seizures should be suspected anytime that a pet undergoes sporadic, unexplained behavioral changes.
What causes seizures in cats? Potential causes are numerous and include viral infections (e.g., distemper, FIP), toxoplasmosis, fungal infections (e.g., cryptococcosis), epilepsy, hydrocephalus, brain tumor, intestinal parasites, low blood sugar, low blood calcium, insecticide poisoning, and heat stroke. Sometimes the cause cannot be determined; if so, seizure episodes are termed “idiopathic.”
Because causes of seizures are so numerous, a thorough examination and blood workup by a veterinarian is warranted whenever a pet exhibits seizures. In some cases, managing or eliminating an underlying cause will eliminate the seizures. In others, such as with idiopathic epilepsy, there is no known cause, yet by ruling out the other potential causes and establishing a pattern of occurrence, most cases can be effectively managed with anticonvulsant medications.
With idiopathic epilepsy, seizures can begin at any stage in life, yet, for the most part, they begin around 1 to 3 years of age. Seizures themselves are rarely life-threatening, unless some physical harm comes to the pet as a result of the fit.
The typical seizure or epileptic fit has three stages, or phases. The first of these, the preictal phase, is marked by anxiety and restlessness on the part of the pet. The actual period of the seizure activity, ictus, follows next. Its duration might be for only a few seconds or it might be minutes.
Certainly, the longer the seizure lasts, the more dangerous it is to the health of the pet. The postictal phase following the seizure is characterized by an overall depression or confusion. P
ostictal pets can appear to be blind, running into walls and objects, or they might just sleep a lot. This phase can last for a few hours or for days, with the pet returning to its normal state after its conclusion.
There is one seizural presentation called status epilepticus that can prove fatal to a pet. This condition is characterized by a cluster of seizure events occurring in quick succession.
Unless appropriate emergency medication is administered intravenously to stop the seizures, these cats can lapse into a coma and die. As a result, prompt recognition and action on the part of the pet owner is essential.
When attempting to diagnose the cause of seizural activity, veterinarians will first look at the age and the type of pet involved. For example, seizures occurring in pets under 1 year of age commonly result from birth defects or from infectious diseases, such as intestinal parasites, whereas seizures occurring in a very old cat often indicate kidney failure or cancer.
Seizures occurring in a pregnant cat or one that has just given birth are usually caused by “milk fever,” or low blood calcium. Finally, as mentioned above, certain breeds are prone to idiopathic epilepsy.
A good history is also vital to help determine the cause of the seizures. Does the pet have access to any type of poison? Has the pet ever suffered any type of physical trauma, such as being hit by a car? Has the intensity of the seizures gradually been getting worse or increasing in frequency? The answers to these and other questions can help a veterinarian narrow the choices.
A complete blood profile and urinalysis should be performed to help rule out the metabolic and infectious causes of seizures. Radiographs and ultrasound can prove to be helpful in certain instances as well.
If no underlying cause can be found, and the history supports it, a diagnosis of idiopathic epilepsy is made and treatment is started on this premise.
For cases other than idiopathic epilepsy, treatment is geared toward correcting or managing the underlying problem, whether it is kidney failure, poisoning, low blood sugar, or another condition. In instances in which idiopathic epilepsy is suspect, anticonvulsant medications can be used to control or even eliminate the seizural activity.
Determining the exact dosages of anticonvulsant medications might require frequent adjustments at the start in order to accommodate the pet’s individual needs. Pets on anticonvulsant medication may need liver function tests performed annually, since some of these medications can damage the liver over the long term.