Answer by  
                                                                                          Latin4 (11170)
                                                            
                          
                          
                                                           It will cause bad breath, but i never heard of it causing seizures. Make sure that your child is brushing his tongue. This is a major cause of bad breath. See a Physician about the sinus infection. He will know what you should do or not do. Also be sure that he is learning to floss.