Hematoceles, 411 –412 , 415 Hematochezia, 213 , 218 , 220 Hematologic abnormalities, 692 Hematologic dysfunction, definition, 77 t Hematologic emergencies, 769 anemia, 769 –770 blood loss, 770 –773 decreased red blood cell production, 777 hemolytic anemia, 773 –776 hemophilia, 795 –797 heparin-induced thrombocytopenia, 790 –791 , 791 t hypercoagulability, 798 –801 immune thrombocytopenia, 787 –790 methemoglobinemia, 776 –777 neonatal thrombocytopenia, 790 neutropenia, 785 –787 nonimmune thrombocytopenia, 791 sickle cell disease, 779 –783 , 781 t–782 t transfusion reactions, 801 Hematoma, 1388 Hematometrocolpos, 130 Hematuria, 529 approach to, 238 f causes common, 236 t life-threatening, 236 t principal, 236 t differential diagnosis, 235 evaluation and decision, 235 –239 history, 237 pathophysiology, 235 physical examination, 237 Heme protoporphyrin, 294 Hemiatlas, 330 Hemodialysis, 694 , 876 Hemoglobin, 417 , 419 , 421 Hemoglobinopathies, 420