Gastroenteritis, 569 –570 with dehydration, 501 t in infants, 504 Gastroesophageal reflux disease (GERD), 102 , 105 , 133 , 136 , 138 , 330 , 360 , 366 , 369 , 372 , 378 –381 , 480 , 482 , 493 , 515 , 548 , 552 –553 , 742 –743 , 897 , 946 , 948 Gastrografin, 132 Gastrointestinal (GI) bleeding assessment, 213 –214 diagnostic approach to, 220 f establishing level of, 213 –214 , 214 f foreign bodies, 732 , 733 f gastrointestinal vascular malformations, 732 hemolytic uremic syndrome (HUS), 731 –732 Henoch–Schönlein purpura (HSP), 732 imitators, 213 lower, 218 –220 severity, 213 upper, 214 –218 Gastrointestinal emergencies abdominal emergencies, 742 –744 acute viral hepatitis, 740 –741 Alagille syndrome, 736 biliary tract disease, 734 –735 cholelithiasis, 736 dietary protein gastrointestinal disorders, 730 –731 gastrointestinal bleeding causes, 724 liver disease, 737 –739 lower GI bleeding, 728 –730 Mallory–Weiss tears, 728 pancreatitis, 732 –734 peptic ulcer disease, 727 –728 portal hypertension, 739 postexposure prophylaxis, 742 upper gastrointestinal bleeding, 724 –726 Gastrointestinal foreign body, 206 –210 Gastrointestinal (GI) tract tumors, 914 –915