The commonest presentation is periumbilical pain associated with autonomic and functional symptoms and other painful conditions. Thus, on initial presentation RAP may mimic any acute abdominal disorder, and may prompt extensive evaluation and unnecessary invasive investigation. In their seminal study, Apley and Naish failed to identify an organic disease in 90% of children suffering from this problem but recent studies have found organic pathologies in a higher percentage of affected children.
Nevertheless, the majority of children with this condition still have no identifiable organic disorders. Numerous organic disorders lead to abdominal pain; in most, the pathophysiology is related to infection (e.g. urinary tract infection), inflammation (e.g. Crohn disease) or distension or obstruction of a hollow viscus (e.g. obstructive uropathy).