Markers for Early Diagnosis of Sepsis

Abstract

Sepsis is defined as the presence of an infection accompanied by systemic inflammatory response syndrome. Systemic inflammatory response syndrome is defined as the presence of 2 or more of the following: temperature greater than 38.5°C or less than 36°C ; pulse rate greater than 90 beats/min; and WBC count greater than 12,000/mm3 or less than 4,000/mm3, or greater than 10% immature band forms. Severe sepsis is defined as the presence of sepsis and 1 or more organ dysfunctions. Septic shock is defined as the presence of sepsis and refractory hypotension. A series of pathogenic events are responsible for the transition from sepsis to severe sepsis/septic shock. The initial reaction to infection is a neurohumoral, generalized pro- and anti-inflammatory response. This begins with a cellular activation of monocytes, macrophages, and neutrophils that interact with endothelial cells through numerous pathogen recognition receptors. Early goal-directed resuscitation has been shown to improve survival for emergency department patients presenting with septic shock, Resuscitation is directed toward: Central venous pressure 8–12 mmHg, mean arterial pressure (MAP) ≥65mm Hg, urine output ≥0.5 mL/kg/hr, central venous (superior venacava) or mixed venous oxygen saturation≥70% or ≥65%, respectively. Intravenous antibiotic therapy should be started as early as possible and within the first hour of recognition of septic shock and severe sepsis without septic shock. Antimicrobial regimen should be reassessed daily to prevent the development of resistance, to reduce toxicity, and to reduce costs. Appropriate cultures should be obtained before antimicrobial therapy is initiated if such cultures do not cause significant delay in antibiotic administration. Hyperprocalcitoninemia in systemic inflammation or infection occurs within 2 to 4 hours, often reaches peak concentrations in 8 to 24 hours, and persists for as long as the inflammatory process continues. The half-life of PCT is approximately 24 hours; therefore, concentrations normalize fairly quickly with the patient’s recovery. PCT <0.5 ng/mL is considered normal, whereas levels >10 ng/mL are considered significantly elevated. Serum concentrations between 2 to 10 ng/mL are considered suggestive of sepsis, whereas PCT concentrations between 0.5 to 2 ng/mL indicate the possibility of sepsis but do not rule out other causes of elevated PCT. CRP is an acute-phase reactant and CRP level is used for the diagnosis of bacterial infections but that lack specificity for