My 5 year old has had 2 boughts with pancreatitis 4 1/2 months apart. Her lipase levels get over 18,000 and her amylase levels get over 1,500. They cannot find the cause. Have your son checked for cystic fibrosis (a "sweat test" performed), checked for pseudocysts (from ultrasound), then possibly genetic testing (we are pursuing that now). If he has a certain gene abnormality, then he could be suseptible to pancreatitis. We are also concerned that our child had a flu shot one month before the first attack, then had her MMR and chickenpox vaccines one month before the second attack. Has your son had any immunizations recently?
Make sure he's checked for autoimmune pancreatitis. In addition, you may want to inquire about the state of his gallbladder as in some cases gallbladder issues and pancreatic issues 'go together.' It's not unknown for a child to have GB problems.