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Friday, November 22, 2013

My Dog Just Had A Seizure!

One of the most awful and disconcerting things a pet owner may suffer is watching their pet experience a grand mal seizure. These seizures are often violent, and the pet seems to be dying right in front of you. They usually fall over, their eyes roll back in their heads, and there are uncontrollable body movements. In addition, some will urinate and/or defecate on themselves. It is a terrible, terrible thing to see.

The good news is that a single seizure is rarely as serious as it appears. They usually last no more than a couple of minutes (although they seem to last forever), and after some recovery time, the dog returns to normal. As with most medical problems, there are some exceptions.

Some dogs who have a seizure, only have a single one, and then are fine. For this reason, I usually do not do a full work-up on a young adult dog who has had a single seizure, has no other symptoms, and has a normal physical exam. However, if a dog is less than a year old, older than five years old, has other symptoms, or has had more than one seizure; that dog will need a full work-up.

By far, the most common cause of seizures is a disease called Idiopathic Epilepsy. Epilepsy usually first appears in dogs between the ages of one and five. There is no known cause, but certain breeds seem to be predisposed. There is no test for epilepsy, so the diagnosis is made by ruling out other causes of seizures. So, what are some other causes of seizures? The list is long, but includes: head trauma, toxins, metabolic disorders (low blood sugar, kidney disease, liver disease), congenital brain disorders (such as hydrocephalus), cancer, meningitis, heart disease, and "stroke." My typical work-up for a seizure dog includes an ECG, CBC, blood chemistries, blood pressure, and a thyroid test. If these tests are all normal, but the dog is showing other neurologic symptoms or is not responding to treatment, I refer the dog to a specialist who can do more advanced testing such as CT scan or MRI.

My first choice anti-seizure drug for epileptics is phenobarbital. Phenobarbital is very effective in most cases and is fairly inexpensive (the dog will be on medication for life). There are potential side-effects of phenobarbital which include transient sedation, increased appetite, and most significantly - liver toxicity. The liver problem is uncommon, but we closely monitor liver values on our patients who take phenobarbital. For those patients whose seizures are not adequately controlled with phenobarbital, I usually add potassium bromide. When combined with phenobarbital, potassium bromide is a very effective anti-seizure drug, and is also fairly inexpensive. Dogs on potassium bromide have an increased risk for pancreatitis.

There are newer anti-seizure drugs on the market, which are significantly more expensive. However, these drugs tend to have fewer side-effects, and are sometimes effective in patients not responding to (or who are having side-effects from), phenobarbital or potassium bromide.

A recent study showed that the sooner an epileptic dog is put on medication, the better the medication will work, and lower doses will be needed. Historically, veterinarians (including myself) tended to not start anti-seizure drugs until the patient was having seizures with unacceptable frequency ("unacceptable" was based on the owner's tolerance, but I often would suggest that more than every two months was "unacceptable.") Since the newer information has come out, I strongly urge that my epileptic patients start medication after the second seizure. Being able to use lower doses of anti-seizure drugs (lower-doses = less chance for side-effects) with better results is definitely in the best interest of the patient!