If bloody<unk>  use caution with beginning antibiotics in ED before stool culture results
Some studies demonstrate antibiotic treatment in setting of E.coli O157:H7 leads to increasing risk of hemolytic uremic syndrome (HUS)
Diarrhea 
Viral
Constipation 
Rotavirus
Constipation
Norovirus, Norwalk virus
Sedation 
Enterovirus