There are metabolic syndromes in
children presenting with nausea, vomiting
and abdominal pain. If there are other manifestations, sometimes undiagnosed cause of abdominal pain is something called porphyria, for which specific testing exists. Also, if there is suspiscion based on multiple other symptoms, mitochondrial disorders can present with neurologic abnormalities along with GI symptoms. Conditions such as Cyclic vomiting can also present with episodes of vomiting with no underlying cause.