Epilepsy causes mild or severe seizures. Seizures may present unusual behaviour, such as staggering, running anxiously as if being chased, or hiding. Episodes are scary to watch, but the long-term prognosis is generally excellent. Seizures can also be caused by many things, such as infectious diseases that affect the brain, tumours, metabolic disorders, exposure to poisons, and more. If your dog has seizures, you must take them to the vet for examination.