When I was first diagnosed with thyroid cancer, I didn't feel any odd lumps or nodules in my neck, but I was suffering from muscle weakness, tiredness and getting constant colds. After a particularly nasty bug I noticed that my lymph nodes never seemed to go down in size.
SIRS is nonspecific and can be caused by ischemia, inflammation, trauma, infection, or several insults combined. Thus, SIRS is not always related to infection. Venn diagram showing overlap of infection, bacteremia, sepsis, systemic inflammatory response syndrome (SIRS), and multiorgan dysfunction.
Systemic inflammatory response syndrome is an inflammatory state affecting the whole body. It is the body's response to an infectious or noninfectious insult. Although the definition of SIRS refers to it as an inflammatory response, it actually has pro- and anti-inflammatory components.