Fast Five Quiz: How Much Do You Know About Systemic Inflammatory Response Syndrome?

Michael R. Pinksy, MD, CM, Dr(HC), FCCP, MCCM


February 12, 2018

Because infectious SIRS etiologies have a high mortality if not effectively treated, and because effective treatment for infection often requires bacteriologic identification of the inciting organism, priority for bacteriologic cultures in the diagnostic workup needs to be stressed.

A white blood cell count of greater than 12,000/µL or less than 4000/µL or with greater than 10% immature (band) forms on the differential is a criterion for SIRS. An increased percentage of bands is associated with an increased incidence of infectious causes of SIRS.

Blood lactate levels are often measured in critically ill patients. These are thought to be indicators of anaerobic metabolism associated with tissue dysoxia. Although a reasonable presumption in patients presenting with circulatory shock and trauma, in septic patients they reflect more the inflammatory burden rather than level of tissue hypoperfusion and, as such, usually do not decrease, if elevated, in response to fluid resuscitation. Levels are commonly elevated from increased peripheral intraorgan production, reduced hepatic uptake, and reduced renal elimination. Numerous studies have found that lactate levels correlate strongly with mortality.

Leptin, a hormone generated by adipocytes that acts centrally on the hypothalamus to regulate body weight and energy expenditure, is an emerging marker that correlates well with serum interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-alpha) levels. Using serum leptin levels with a cutoff of 38 µg/L, researchers have been able to differentiate sepsis from noninfectious SIRS with a sensitivity of 91.2% and a specificity of 85%. This test is not yet readily available for clinical practice in the United States.

For more on the workup of SIRS, read here.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.