End-organ dysfunction
Examples of end-organ dysfunction include the following:
Lungs: acute respiratory distress syndrome (ARDS) (PaO2/FiO2 ratio < 300), different ratio in pediatric acute respiratory distress syndrome
Brain: encephalopathy symptoms including agitation, confusion, coma; causes may include ischemia, bleeding, formation of blood clots in small blood vessels, microabscesses, multifocal necrotizing leukoencephalopathy
Liver: disruption of protein synthetic function manifests acutely as progressive disruption of blood clotting due to an inability to synthesize clotting factors and disruption of metabolic functions leads to impaired bilirubin metabolism, resulting in elevated unconjugated serum bilirubin levels
Kidney: low urine output or no urine output, electrolyte abnormalities, or volume overload
Heart: systolic and diastolic heart failure, likely due to chemical signals that depress myocyte function, cellular damage, manifest as a troponin leak (although not necessarily ischemic in nature)More specific definitions of end-organ dysfunction exist for SIRS in pediatrics.
Biomarkers
Biomarkers can help diagnosis because they can point to the presence or severity of sepsis, although their exact role in the management of sepsis remains undefined. A 2013 review concluded moderate-quality evidence exists to support the use of the procalcitonin level as a method to distinguish sepsis from non-infectious causes of SIRS. The same review found the sensitivity of the test to be 77% and the specificity to be 79%. The authors suggested that procalcitonin may serve as a helpful diagnostic marker for sepsis, but cautioned that its level alone does not definitively make the diagnosis. A 2012 systematic review found that soluble urokinase-type plasminogen activator receptor (SuPAR) is a nonspecific marker of inflammation and does not accurately diagnose sepsis. This same review concluded, however, that SuPAR has prognostic value, as higher SuPAR levels are associated with an increased rate of death in those with sepsis. Serial measurement of lactate levels (approximately every 4 to 6 hours) may guide treatment and is associated with lower mortality in sepsis. Differential diagnosis
The differential diagnosis for sepsis is broad and has to examine (to exclude) the non-infectious conditions that may cause the systemic signs of SIRS: alcohol withdrawal, acute pancreatitis, burns, pulmonary embolism, thyrotoxicosis, anaphylaxis, adrenal insufficiency, and neurogenic shock. Hyperinflammatory syndromes such as hemophagocytic lymphohistiocytosis (HLH) may have similar symptoms and are on the differential diagnosis.