A systemic inflammatory response to a variety of clinical insults, characterized by two or more of the following conditions: (1) fever > 38 degrees C or hypothermia < 36 degrees C; (2) tachycardia > 90 beat/minute; (3) tachypnea > 24 breaths/minute; (4) leukocytosis > 12,000 cells/cubic mm or 10% immature forms. While usually related to infection, sirs can also be associated with noninfectious insults such as trauma; burns; or pancreatitis. If infection is involved, a patient with sirs is said to have sepsis.