Systemic Inflammatory Response Syndrome (SIRS) and Sepsis - An Ever-evolving Paradigm.

Abstract

Sepsis remains the most common cause of mortality in children from developing countries [1, 2]. Systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis or septic shock reflects a physiologic continuum with increasing severity of disrupted balance between pro and anti-inflammatory responses of the body. The International Consensus Conference on Pediatric Sepsis and Organ Dysfunction modified the sepsis definitions for adult patients incorporating age-specific cut-offs for vital signs and laboratory data [3]. These definitions were devised to identify sepsis at an early stage to facilitate effective interventions to contain infection and, to prevent life threatening inflammatory reaction to infection. The distinct feature of pediatric SIRS is the mandatory requirement of either abnormal temperature or leukocyte count for diagnosis. This is important because abnormal heart rate and respiratory rates are common in children and do not necessarily indicate SIRS. Diverse clinical conditions like burns, pancreatitis, major trauma, surgery and sepsis can meet criteria for SIRS. Thus it represents a state of relative inflammatory activation and is not a diagnosis per se. In United States, the overall estimated prevalence of severe sepsis in children had increased from 0.56 cases per 1000 children in 1995 to 0.63 cases per 1000 children in 2000 to 0.89 cases per 1000 children in 2005 [4–6]. In a recent international multicenter point prevalence study involving network of 128 pediatric intensive care units, the prevalence of severe sepsis was 8.2% (95%CI, 7.6–8.9%) and inAsia was 15.3% (11.7–19.5 %) [7]. These trends of prevalence of disease are possible only if such epidemiological data is rigorously documented. In this issue of the journal, Ganjoo et al. in their hospital based descriptive point prevalence study have evaluated the clinical and demographic profile of children, admitted to the hospital [8]. The prevalence of SIRS amongst hospitalized children in the index study was 23 % [8]. However, this study did not include children from the emergency department or surgical or oncology wards. Thus, the data might not have been representative of all cases of non-infective SIRS [8]. Prevalence of sepsis in this study was 14.9 % (129/865), severe sepsis was 3.4 % (30/865) and septic shock was 2.1 %. (19/865). In a similar study from Latvia in 943 hospitalized children with fever, 72 % had SIRS, 8 % had sepsis, 5 % had severe sepsis and 2 % had septic shock [9]. The epidemiology of SIRS and sepsis varies with population in which it is described like inpatients or emergency department or intensive care unit. Among the pediatric intensive care population, reported incidence of sepsis varies from 7.9 to 23 % [10, 11]. The prevalence of sepsis is highest at the newborn and perinatal period and decreases consistently with increase in age. The prevalence of newborn sepsis in US is 9.7/1000 population, infants 2.25/1000 and for children 1–19 y of age it varies from 0.23 to 0.52/1000 population [6]. This age wise distribution of SIRS is different in the index study [8] with age group of 1 to 5 y contributing about 46.7 % (n=94) which is similar to data from other studies [9, 12]. The commonest cause of infective-SIRS in the index study was respiratory tract infection (33 %, n=286) and diagnosis of SIRS was mostly based on abnormal temperature with increased respiratory rate (85 %, n=172) [8]. This affirms with the fact that childhood pneumonia is the most common cause of pediatric severe sepsis worldwide [4, 7]. In the noninfective SIRS group, the commonest cause was acute exacerbation of asthma reported in 34 of the 42 cases. While acute exacerbation of asthma may qualify definition of SIRS, * Jhuma Sankar jhumaji@gmail.com