By Jay McDonnell, DVM, MS, Diplomate ACVIM (Neurology)
When older pets (age 10 year or older) have a seizure, the owner's first thought typically is, "This has to be a tumor or something else bad. This must be a death knell for my pet." I'd like to assure you: This isn't necessarily true.
Every week in my practice I see geriatric pets that have had seizures. When we do a work-up with MRI and spinal tap, often there are NO terminal conditions present.
Frequently in dogs, the cause of the seizure(s) is a stroke. It's valuable to utilize a CSF tap and MRI to make a diagnosis of stroke as we know that many pets will not get worse. Instead, with treatment using standard anti-convulsants, they recover with minimal deficits. Another advantage to diagnosis is that we are able to anticipate future stroke episodes and prevent them.
Possible causes for seizures in a geriatric pet include hypertension, kidney disease, liver disease, adrenal disease, and hypothyroidism or hyperthyroidism (especially in cats), to name a few.
My approach to stroke in dogs is to have the primary care veterinarian screen for many of these diseases after the initial event to prevent further stroke episodes.
Based on my experience in working up many geriatric animals with late onset seizure disorders who have normal MRIs and spinal tap results AND excellent response to our standard anti-convulsants, I believe that geriatric onset ideopathic epilepsy is a true syndrome in animals.
I encourage my colleagues and pet owners not to give up on an animal who's had a seizure at an advanced age, and who receives an alternate diagnosis other than tumor. Typically when they have a clear brain scan, they can be put on anti-convulsants and will live longer—and die from something else. The owners of those patients are so grateful to have pursued a diagnosis with MRI and CSF tap.
I've spoken to many other veterinary neurologists who report the same findings.
In conclusion: It's important for us to offer this opportunity for a complete diagnosis to owners, and not default to a worst case scenario.
Below: Sample MRIs of dog that has had a stroke.