SIRS (Systemic Inflammatory Response Syndrome)

By | June 8, 2022

SIRS is an acronym for Systemic Inflammatory Response Syndrome. In the context of infections, medicine also speaks of sepsis for this immunological whole-body inflammation. Removal of the inflammatory focus is an important treatment step.

What is SIRS?

Inflammatory reactions are signs of immunological activation. The immune system wants to remove pathogens or other harmful substances from the organism via immunological inflammation. Foreign substances, antigens or abnormal tissue conditions trigger a stimulus that initiates the immunological defense reaction. The respective inflammatory reaction can take place in the affected organs and the surrounding tissues or systematically affect the entire body. For everything about hydronephrosis, please visit

Finally, any stimulus above a physiologically normal level can activate inflammation. This applies to physical stimuli as well as to mechanical stimuli. In addition to thermal, radiation and chemical causes, inflammation can also be caused by allergens or autoallergens and actual pathogens such as viruses. SIRS stands for Systemic Inflammatory Response Syndrome and thus an inflammatory reaction of the entire body.

Instead of a local inflammation, the systemic inflammatory response syndrome is a systemic inflammation that spreads from a directly affected tissue in the body. The clinical picture is similar to blood poisoning. In contrast to sepsis, however, no infections can be detected with SIRS.


Ultimately, sepsis is an infectious special form of SIRS. The systemic inflammatory response syndrome can thus be triggered by even more circumstances than sepsis, but resembles it in its basic properties. The systemic inflammatory reaction without detectable infection can have an immunological origin. However, the clinical picture can also be caused by chemical relationships.

For example, in acute pancreatitis, bile acid backs up in the pancreatic ducts, damaging the epithelium of the pancreas or making it permeable to various substances. Thermal triggers are also possible causes of SIRS. These include, for example, burns of a certain size and severity. Among the mechanical triggers, major surgeries are among the most important causes of SIRS.

In particular, interventions with an extracorporeal circulation are observed as triggers for the inflammatory reactions. In addition to heart surgery, large wound areas can also cause SIRS. Severe trauma, bleeding, ischaemia or anaphylaxis can also be triggers. Serious diseases such as necrotizing pancreatitis are also a possible cause of the systemic inflammatory response of the whole body.

Symptoms, Ailments & Signs

Various parameters indicate the SIRS. However, there are usually only around two of these in a patient at the same time. The criteria for making a diagnosis include, for example, a body temperature below 36 or above 38 degrees Celsius. The same goes for a heart rate above 90 per minute. Tachypneas with respiratory rates above 20 per minute and a paCO2 below 32 mmHg or oxygenation indices below 200 are also conceivable.

A WBC count of less than 4000/mm3 or more than 12000/mm3 can also indicate SIRS. The same applies to less than ten percent immature leukocytes. In the laboratory, hypophosphatemia and thrombocytopenia turn out to be additional markers for SIRS. A drastic drop in fibrinogen or factors II, V and X can also provide clues to the clinical picture.

CRP and ESR are usually highly positive and procalcitonin is constantly increasing. Increasing IL-6 and IL-8 is also indicative as they are the major mediators of the acute phase response.

Diagnosis & course of disease

The doctor makes the diagnosis of SIRS based on the parameters mentioned. At least two of the above criteria must be met for diagnosis. The combination of fever and abnormal leukocytosis is the most common combination in the diagnosis of SIRS and indicates an appropriate or excessive immune response.

A body temperature below 36 degrees Celsius in combination with leukopenia is also known as cold SIRS and indicates an immune deficiency. If two or more of the criteria mentioned are accompanied by a detectable infection, the question is no longer of systemic inflammatory response syndrome but of sepsis. The course depends strongly on the clinical picture in the individual case. Treatment as early as possible improves the prognosis. The initiation of therapy before the detection of possible pathogens is considered the recommended standard.


As the disease progresses, SIRS can cause a range of symptoms and complications. The whole body inflammation initially causes the body to overheat – symptoms such as fever and hyperventilation occur. If the body temperature rises above 41 degrees Celsius, life-threatening cardiovascular problems can occur. If left untreated, it eventually leads to circulatory collapse or heart failure.

Accompanying symptoms such as dehydration and deficiency symptoms can also be fatal if left untreated. Due to the weakened immune system, there is also an increased risk of infections. As a result, inflammation can occur throughout the body, which in the worst case can lead to blood poisoning. If the internal organs or the skin are affected, further complications arise, for example renal insufficiency and abscesses.

The treatment also comes with risks. The administration of antibiotics can lead to gastrointestinal complaints, headaches, muscle and body aches and skin irritations. Even allergies and intolerance reactions cannot be ruled out. Surgery can lead to infection, bleeding and nerve damage. In some cases, allergic reactions to the substances and materials used can also occur.

When should you go to the doctor?

Medical treatment is definitely necessary for SIRS. In the worst case, the person affected can also die due to the symptoms of the syndrome, so early diagnosis is very important. In most cases, the life expectancy of the patient is significantly reduced by SIRS. A doctor should be consulted if the patient suffers from a body temperature that is significantly too low or too high. This can lead to very high-frequency breathing or gasping.

Many of those affected suffer from fever or even loss of consciousness. If these symptoms occur, a doctor must be consulted immediately. A reduced resistance of the immune system can also indicate this disease and should always be examined by a doctor. First and foremost, a general practitioner can be consulted for SIRS. Further treatment is then usually carried out by a specialist. Whether the treatment will lead to success cannot always be predicted. In emergencies, you should go to the hospital or call an ambulance.

Treatment & Therapy

In order to treat SIRS, the focus of inflammation must first be identified. Once the focus of the inflammatory response has been detected, surgical intervention is performed to clean up the focus. Antibiotics are given initially and correspond to broad coverage based on suspicion. This step can be described as calculated therapy. An antibiogram is created to elucidate any resistance.

Thereafter, if necessary, a switch is made to a specified antibiotic therapy. The drug and surgical steps are completed with a volume infusion that produces a CVP above eight to twelve mmHg and a mean arterial pressure above 65 mmHg. If volume administration is not sufficient to achieve values, treatment with vasopressors or positive inotropic agents such as norepinephrine is considered as early as possible.

The therapy pursues a central venous oxygen saturation of more than 70 percent, which is maintained in the further course of therapy. In addition, an ideal Hb concentration with a hematocrit of over 24 to 30 percent is aimed for. If necessary, this value can be achieved by administering concentrated erythrocytes. Ventilation with a tidal volume of six milliliters per kilogram of body weight serves to protect the lungs, with the open-lung concept being pursued with a PEEP above the inflection point.


SIRS is a relatively natural reaction. Severe forms can be prevented by prompt treatment if necessary. Above all, the timely elimination of the inflammatory focus can be described as a preventive measure.


The entire organism is affected by the systemic inflammatory response syndrome (abbreviated as SIRS). If left untreated, the syndrome can develop into life-threatening sepsis with organ failure. In addition to treatment of the underlying disease, medical follow-up care is necessary. The aim is to avoid organic consequential damage and septic shock. For a favorable course of the disease, therapy and follow-up care must take place within one day in good time.

The affected person receives antibiotic and/or anti-inflammatory agents. With the help of the medication, the inflammation should subside, and the vital functions must also be closely monitored. After the emergency treatment, the patient should be out of danger. Care should be taken to prevent SIRS from recurring. Further follow-up care depends on the causative disease and is initiated in the clinic.

In the case of drug therapy, the specialist monitors the healing progress. The aftercare ends with the healing. In the case of surgical treatment, it is scheduled for the medium to long term. After being discharged from the clinic, the patient must see the family doctor at fixed intervals. There the postoperative condition is determined. Follow-up ends when the individual is found to be stable.

You can do that yourself

With this disorder, the possibilities for self-help are limited to taking measures to improve general well-being and strengthen the immune system. The patient’s body can be supported with a balanced diet rich in vitamins. Sufficient oxygen, avoiding environments with pollutants and daily exercise in fresh air help the body to build up its defenses.

In order to alleviate gastrointestinal complaints, it is important to have a food intake that is tailored to the patient’s needs. Alcohol, nicotine, a fatty food or excessive intake of food should be avoided. To stop muscle and joint pain, regular balancing movements, warm baths or massages are recommended. Physical overexertion is to be avoided, as is adopting a one-sided or rigid posture. With the first complaints or when you feel unwell, you should take breaks so that the organism has time to regenerate. If you have a headache, it is advisable to remain calm and reduce stressors as much as possible.

Cognitive training can be used in everyday life to reduce emotional stress and promote inner balance. Various relaxation techniques also help to alleviate existing symptoms. Although no recovery occurs, methods such as yoga or meditation can provide the patient with an improvement in well-being in the area of ​​self-help.

SIRS (Systemic Inflammatory Response Syndrome)