Seizures are, unfortunately quite common in pets. Seizures are much more common in dogs than in cats, but can occur in both. Thankfully, with proper diagnostics and medications we can often keep seizures under control.
Seizures are caused by abnormal brainwaves that start off in a small part of the brain, but are able to spread to other parts of the brain leading to a varying degree of signs. Seizures can look like anything from staring into space, to doing a behavior repeatedly, to full blown convulsions. Seizures can be caused by a number of conditions. The most common cause is idiopathic epilepsy-a seizure disorder that may have its roots in genetics. Other causes can include previous injury or damage to the brain, liver disease, hypothyroidism, brain masses, or other organ dysfunction.
As a general rule, when a pet has its first seizure, we will want to do lab testing to evaluate for metabolic diseases. Depending upon the initial results, additional testing may be recommended. Options even exist for your pet to be evaluated by a neurologist who may recommend advanced diagnostics such as an MRI or CT scan.
Once we have an idea of what led to the seizures, we will proceed with a treatment plan. If the seizures do not appear to be due to an obvious organ dysfunction, we may discuss using an anti-convulsant medication like Phenobarbital. Typically, we only start anti-convulsant therapy if the pet has had more than one seizure in a month, the seizures occur in clusters within a short period of time, or the seizures last longer than 5 minutes at a time. We almost always start therapy, if needed, with Phenobarbital because it is the least expensive and has the longest track record of use and success at managing seizures.
Other anti-convulsants are available to us if they are medically needed.
If anti-convulsants are started, at first the pet may be a bit wobbly on its feet; might drink more water than usual; and may develop an increased appetite. These signs should diminish within three to eight weeks.
Every pet metabolizes Phenobarbital, and other anti-convulsant medicines, differently. These medications also need to reach a certain level in the blood in order to do their job. Therefore, after a few weeks on the medication, we will want to do a blood test to check the Phenobarbital (or other drug) level, and see how your pet is doing. Often, we need to adjust the dose of the medication depending upon your pet’s progress and the blood levels.
Sometimes, Phenobarbital can adversely affect the liver-especially with long term usage. To monitor for problems, we will want to do a liver function test (called a bile acids) and a Phenobarbital level every six months. If a problem is beginning to develop, we may need to adjust the dosage, or change to another anti-convulsant altogether.
Occasionally, a pet will not respond well to Phenobarbital alone and we might have to add a second drug or transition to another drug.Whatever the plan is, it is important to never discontinue anti-convulsant therapy abruptly-stopping the medication, or in some cases even missing doses of medication can cause rebound seizures.