My Lady is an epileptic so I know more about the disease than I'd like to.
Seizures can be a symptom of something like a liver shunt. Thyroid malfunction can also cause seizures. As the others have said, you should have a bile acids test done on Coco if she's never had one done before. Coco also should have a thyroid panel and CBC. If everything comes back normal, then you just wait and see if she has another one.
If she continues to have seizures with no known cause, she would be diagnosed with idiopathic (organic) epilepsy, what my Lady has.
This website is a wealth of information about seizures, from what to do during one to what can cause them.
http://www.canine-epilepsy-guardian-angels.com/