Workup
Ask yourself -- again -- why is this not... appendicitis-torsion-intussusception-etc.
Admit sick children, but most go home, so...
Non-bloody, febrile -- no workup necessary; precautionary advice
Non-bloody, afebrile -- be more skeptical, but generally same as above
Bloody, febrile -- stool culture, follow up; do not treat empirically unless septic and admitted. Culture will dictate treat/no treat/how.
Bloody, afebrile -- evaluate for hemolytic uremic syndrome, especially if under 5 years old: CBC, chemistries, UA, stool culture