Systemic Inflammatory Response Syndrome (SIRS) is a widespread inflammation of the body with no known infectious cause. When SIRS develops in response to a known or suspected infection, it is known as sepsis. SIRS is treated as a medical emergency requiring prompt intervention and treatment, and it can lead to a variety of complications, even with treatment.
There are four diagnostic criteria for SIRS, two or more of which must be present for a patient to be diagnoses. The first is a rapid heart rate, defined as a heart rate higher than 90 beats per minute. An elevated respiratory rate is another key indicator of SIRS, as is a temperature which is either elevated from normal, or substantially lower than normal. The final symptom is an abnormally high or low white blood cell count, which indicates that the body is trying to fight inflammation.
The widespread inflammation of the body which characterizes SIRS can lead to several complications. One of the most serious is permanent organ damage or failure, caused by a spread of the inflammation to the organs. SIRS can also cause the patient to go into shock as his or her body attempts to cope with the inflammation, and it can cause dangerously low blood pressure as a result of hugely dilated blood vessels.
One of the key aspects of treatment involves identifying the cause, because it can be difficult to eliminate the inflammation without getting rid of the root cause. In the case of patients with low blood pressure, fluids may be given to increase blood volume and cause an elevation in blood pressure. Cooling or warming blankets can be used to stabilize the body's core temperature, and in extreme cases, a pacing device or respirator may be used to cope with the elevated heart rate and breathing.
Underlying unidentified infections are a potential cause of SIRS, as are trauma, surgical complications, severe burns, heart attacks, drug overdoses, immunodeficiency disorders, and anaphylactic shock, among others. Once the patient has been stabilized, medical staff will work on determining the cause of the SIRS, with the use of interviews to take medical history and medical testing such as blood draws and medical imaging to look for tell-tale signs of the inflammation's cause. In the case of patients who cannot be interviewed, family members and friends may be interviewed to gather information about the patient and the activities he or she was most recently engaged in.