الفهرس 
SIRS and SepsisOnly 14 pages are availabe for public view
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Abstract
Increased rates of infection with anti-microbial resistant bacteria, especially methicilline-resistant staphylococcus aureus (MRSA), have focused attention on early detection of infection and the adoption of measures to control their spread. Similarly, the increased incidence of sepsis, an unusual systemic response to infection which occurs in some patients, has stimulated great interest in identifying infected patients at risk and intervening early. When this condition progress to severe sepsis (characterized by organ dysfunction) and septic shock (associated with hypotension), mortality rate is high. Like MRSA, sepsis is no longer limited to hospitalized patients but has begun to appear as a potential complication of community-acquired infections, especially pneumonia. Patients with suspected severe sepsis now account for over 500,000 visit emergency department annually (Wang et al, 2007).
The most recent sepsis definition conference suggested an expansion of the diagnostic criteria, and several of additional variables involving inflammatory markers such as CRP and PCT (Levy et al, 2003).
Scientific progress has resulted in an endless array of potential mediators in sepsis and yet-to-be-characterized interactions pathways. The ability to diagnose and predict severity of sepsis is limited by the insensitive and non specific clinical and laboratory parameters that are currently available. Based on rapidly expanding knowledge about the pathophysiology of the host inflammatory response to infection, biomarkers may provide a much-needed solution. The current evidence suggests that IL-6 and CRP are likely to remain sentinel markers of inflammation and Infection but are too non specific for further use (Ventetuolo and Levy, 2008).
PCT is prohormone of calcium homeostasis hormone, calcitonin (Weglohner, 2001). In the early 1990s, elevated PCT in patients with invasive infection was discovered (Assicot et al, 1993). It has been shown that many tissues throughout the body are the source of PCT during infection (Muller et al, 2001) and that PCT is probably part of the abnormal systemic response that leads to severe sepsis. PCT was soon used to differentiate bacterial infection from non infectious systemic inflammation (Eberhard et al, 1997) and to identify patient with severe sepsis (Karazai et al, 1997). Over the past decade numerous studies –mostly PCT, There has been significant controversy, and PCT clearly has some limitations (Christ-Crain and Muller, 2005).
A recent critical review of the published literature regarding PCT concluded that the test has considerable utility in the diagnosis of severe sepsis (Becker et al, 2008), and PCT has been cited in recent guidelines as useful in identification of patient with infection who are at increased risk of developing sepsis (O’Grady et al, 2008).
In the past, the clinical utility of PCT could not be performed as rapidly as other tests needed in the support of critically ill patients. But commercially available assays for PCT are now capable of producing results within 30 minutes, and also more analytically sensitive than the so-called first generation assays. These will allow PCT measurements to be more precise, less expensive, and more relevant to clinical decision making. They may also extend the usefulness of PCT beyond the diagnosis of sepsis (Becker et al, 2008).
In Europe, there has been great interest in using PCT levels to help decide whether or not to initiate antibiotic therapy and to guide its duration. This antibiotic steward ship can prevent antibiotic over use, reducing cost as well as decreasing the risk of developing bacterial resistance. The initial focus was on lower respiratory tract infection (Christ-Crain et al, 2004), but the approach has also been applied to community-acquired pneumonia (Christ-Crain et al, 2006). As well as severe infection itself (Nobre et al, 2008).
Based on recently published studies, PCT likely will enhance clinician ability to diagnose the presence of infection in critically ill patients and perhaps guide anti-microbial treatment (Ventetuolo et al, 2008).
In the future, PCT may guide triage in the emergency department for infectious diseases in a manner similar to the use of troponin for patients suspected of having acute coronary syndrome. PCT levels may allow physicians to admit patients at high risk of developing severe sepsis, and discharge those as out patients whose infection may be safely treated. PCT is the only one of the emerging laboratory markers of sepsis proposed as adjuncts to clinical evaluation of sepsis