Introduction

Seizure disorders are not particularly difficult to detect. The difficult part is determining the cause of the seizures.

How Seizures are Diagnosed

Presented with a dog suspected of having a seizure disorder, most veterinarians will recommend a complete blood count, serum biochemistry panel and urinalysis, after obtaining a complete history of the dog’s symptoms and conducting thorough physical and neurological examinations. The results of the blood and urine tests may reveal metabolic disorders, intoxication, liver or kidney disease or other abnormalities. In dogs with primary epilepsy, the results of these tests usually are normal. The veterinarian may also recommend an electrocardiogram (ECG) to assess the health of the dog’s heart, and thoracic (chest) and abdominal radiographs (X-rays) to look for any visible abnormalities. Dogs with heart disease that involves abnormal heart rhythms (arrythmias) can have clinical signs that mimic primary seizures. If the patient is a puppy under 6 months of age, a serum bile acid assay may be performed to rule out a portosystemic shunt as a cause of hepatic (liver) encephalopathy.

Advanced diagnostics will include more detailed assessment of the brain using computed tomography (CT or CAT scan) or magnetic resonance imaging (MRI). These sophisticated diagnostic tools can identify tumors or other lesions in the brain or skull. Typically, they are only available at veterinary teaching hospitals and specialty clinics. Radiographs of the skull are normally unremarkable and not particularly helpful, unless the cause of the disorder is direct trauma to the head. A spinal tap to obtain a sample of cerebrospinal fluid (CSF) can help to identify certain types of neurological disease and inflammation. If exposure to a particular toxin is suspected, diagnostic blood tests may be productive, as well.

Special Notes

Dogs under 6 months or over 5 years of age that present with signs of seizures probably do not have primary epilepsy. Structural brain abnormalities are a more likely cause of their symptoms. Research is underway to identify a genetic marker for epilepsy. Hopefully, one day breeders will be able to identify dogs as carriers of the “epilepsy gene(s),” so that they can eliminate them from responsible breeding programs.