Please advise what is the difference between shaking baby syndrome and epilepsy?

Very different. Shaking baby syndrome is a brutal traumatic event which can lead to death in an infant, and I presume you are instead asking about a small child experiencing a "shuddering episode", which is not a seizure usually. A pediatrician can sort this out. Epilepsy implies more than one true seizure. Hopefully, I have interpreted your question.