abdominal pain after eating

My niece is being tested for porphyria. I have read up on the disorder, but could not find any reference to severe pain after eating. She gets severe pain in her abdomen and extreme burping after eating. Then she goes in and out of a "faint" for 45-60 mins, alternating with panting and belching, and waking up to moan and scream, then slump over again. When she comes to, she is very confused, doesn't know her own mother, where she is., etc. Then she will snap out of it, and cannot remember what she ate. She will giggle about it. Does any of this sound like porphyria? I think some symptoms do, but would love to hear from anyone who has it or takes care of someone with it. Thanks.