**6. Systemic inflammatory response syndrome (SIRS)**

One complication that may arise as shock progresses is the development of **Systemic Inflammatory Response Syndrome (SIRS)**. While SIRS may not always be present in the progression of shock, its presence heralds the onset of a more serious syndrome mentioned earlier; Multiple Organ Dysfunction Syndrome (MODS). SIRS is defined as an "exaggerated defense response to a noxious stressor" and can be due to


#### **Table 3.**

*Diagnostic criteria for SIRS is the presence of any two of the above criteria.*

insults such as infection, trauma, surgery, acute inflammation, and ischemia or reperfusion injury [3]. The relationship between shock and SIRS is not linear and one does not necessarily arise from the other. Shock may progress in the absence of SIRS depending on the etiology and type of shock. Infection is the most common cause of SIRS and is termed sepsis. In the early phases of septic shock, a cause of distributive shock discussed later, pathological stimuli result in cellular and immunological activation. This cellular activation leads to the release of a variety of chemokines including histamine, kinin, prostaglandins, leukotrienes and complement. Over activation of this system results in an imbalance between pro-inflammatory and anti-inflammatory mechanisms. Diagnostic criteria for determining SIRS are outlined in **Table 3**.

The outcomes of this imbalance occur globally, are a result of increased proinflammatory activity and are listed below:

