What Causes Nausea And Increased Flatulence In A Child?

Hi my son is almost 13. When he was younger he had been diagnosed with seizures. He has been off of meds for a long time with no problems. Recently he has started to experiencing nausea, flashing lights, arm and leg jerking with no loss of consciousness, increased heart rate, sweating, and increased flatulence. Do think it is possible that his seizures have returned?