Discriminative value of inflammatory biomarkers for suspected sepsis

Differential diagnosis between bacterial infection and neoplastic fever in patients with advanced urological cancer: the role of procalcitonin

It is difficult to determine the cause of high fever in patients with advanced cancer, because they tend to have both neoplastic fever and concomitant bacterial infections with elevated white blood cells and C-reactive protein levels. Procalcitonin has been reported to be a valuable marker for bacterial infections in a wide range of clinical scenarios. However, there have been no studies regarding the usefulness of procalcitonin to differentiate between febrile episodes caused by bacterial infections and neoplastic fever in patients with advanced urological cancer. In the present study, 37 febrile episodes were retrospectively analyzed. Although there were no differences in white blood cell number, C-reactive protein level or body temperature between bacterial infections and non-bacterial infections, procalcitonin levels were significantly higher in the former than the latter. Our findings suggest that measurement of procalcitonin might be valuable to determine the cause of febrile episodes in patients with advanced urological cancer, and can help clinicians to make appropriate decisions for treatment.

Usefulness of a selective neutrophil elastase inhibitor, sivelestat, in acute lung injury patients with sepsis

BACKGROUND

Neutrophil elastase plays a crucial role in the development of acute lung injury (ALI) in patients with systemic inflammatory response syndrome (SIRS). The clinical efficacy of the neutrophil elastase inhibitor, sivelestat, for patients with ALI associated with SIRS has not been convincingly demonstrated. The aim of this study was to determine if there are clinical features of patients with this condition that affect the efficacy of sivelestat.

METHODS

This was a retrospective study of 110 ALI patients with SIRS. Clinical information, including the etiology of ALI, the number of organs failing, scoring systems for assessing the severity of illness, and laboratory data, was collected at the time of diagnosis. Information on the number of ventilator-free days (VFDs) and changes in PaO(2)/F(I)O(2) (ΔP/F) before and 7 days after the time of ALI diagnosis was also collected. The effect of sivelestat on ALI patients was also examined based on whether they had sepsis and whether their initial serum procalcitonin level was ≥0.5 ng/mL.

RESULTS

There were 70 patients who were treated with sivelestat and 40 control patients. VFDs and ΔP/F were significantly higher in the treated patients than in the control patients. However, there was no significant difference in the patient survival rate between the two groups. Sivelestat was more effective in ALI patients with a PaO(2)/F(I)O(2) ratio ≥ 140 mmHg or sepsis. Sivelestat significantly prolonged survival and led to higher VFDs and increased ΔP/F in septic patients and patients with initial serum procalcitonin levels ≥ 0.5 ng/mL.

CONCLUSION

The results may facilitate a future randomized controlled trial to determine whether sivelestat is beneficial for ALI patients with sepsis.

Procalcitonin as a diagnostic marker for sepsis: a systematic review and meta-analysis

BACKGROUND

Procalcitonin is a promising marker for identification of bacterial infections. We assessed the accuracy and clinical value of procalcitonin for diagnosis of sepsis in critically ill patients.

METHODS

We searched Medline, Embase, ISI Web of Knowledge, the Cochrane Library, Scopus, BioMed Central, and Science Direct, from inception to Feb 21, 2012, and reference lists of identified primary studies. We included articles written in English, German, or French that investigated procalcitonin for differentiation of septic patients--those with sepsis, severe sepsis, or septic shock--from those with a systemic inflammatory response syndrome of non-infectious origin. Studies of healthy people, patients without probable infection, and children younger than 28 days were excluded. Two independent investigators extracted patient and study characteristics; discrepancies were resolved by consensus. We calculated individual and pooled sensitivities and specificities. We used I(2) to test heterogeneity and investigated the source of heterogeneity by metaregression.

FINDINGS

Our search returned 3487 reports, of which 30 fulfilled the inclusion criteria, accounting for 3244 patients. Bivariate analysis yielded a mean sensitivity of 0 · 77 (95% CI 0 · 72-0 · 81) and specificity of 0 · 79 (95% CI 0 · 74-0 · 84). The area under the receiver operating characteristic curve was 0 · 85 (95% CI 0 · 81-0 · 88). The studies had substantial heterogeneity (I(2)=96%, 95% CI 94-99). None of the subgroups investigated--population, admission category, assay used, severity of disease, and description and masking of the reference standard--could account for the heterogeneity.

INTERPRETATION

Procalcitonin is a helpful biomarker for early diagnosis of sepsis in critically ill patients. Nevertheless, the results of the test must be interpreted carefully in the context of medical history, physical examination, and microbiological assessment.

FUNDING

Ministry of Education and Research, the Deutsche Forschungsgemeinschaft, Thuringian Ministry for Education, Science and Culture, the Thuringian Foundation for Technology, Innovation and Research, and the German Sepsis Society.

New approaches to sepsis: molecular diagnostics and biomarkers

Sepsis is among the most common causes of death in hospitals. It arises from the host response to infection. Currently, diagnosis relies on nonspecific physiological criteria and culture-based pathogen detection. This results in diagnostic uncertainty, therapeutic delays, the mis- and overuse of antibiotics, and the failure to identify patients who might benefit from immunomodulatory therapies. There is a need for new sepsis biomarkers that can aid in therapeutic decision making and add information about screening, diagnosis, risk stratification, and monitoring of the response to therapy. The host response involves hundreds of mediators and single molecules, many of which have been proposed as biomarkers. It is, however, unlikely that one single biomarker is able to satisfy all the needs and expectations for sepsis research and management. Among biomarkers that are measurable by assays approved for clinical use, procalcitonin (PCT) has shown some usefulness as an infection marker and for antibiotic stewardship. Other possible new approaches consist of molecular strategies to improve pathogen detection and molecular diagnostics and prognostics based on transcriptomic, proteomic, or metabolic profiling. Novel approaches to sepsis promise to transform sepsis from a physiologic syndrome into a group of distinct biochemical disorders and help in the development of better diagnostic tools and effective adjunctive sepsis therapies.

Are circulating levels of CRP compared to IL-6 and PCT still relevant in intensive care unit patients?1)

C-reactive protein (CRP) currently constitutes one of the most widely used parameters for the diagnosis of infections and inflammatory processes, due to simple methods and low costs. However, in recent years, other parameters, such as interleukin 6 (IL-6) and procalcitonin (PCT), have gained in importance. Although these parameters are presently not established everywhere in clinical routine, they provide significant advantages in the diagnosis and monitoring of inflammatory diseases. For instance, in intensive care, the increase in IL-6 levels may indicate inflammatory complications 24 to 48 h prior to the increase in circulating CRP levels. In contrast to CRP, PCT shows a higher specifity for bacterial infections, which facilitates the diagnosis of bacterial infections and sepsis. PCT measurements further allow assessment of therapeutic success and indicate necessary changes in antibiotic therapy. These points raise the question whether CRP measurements should at least in part be replaced by PCT and/or IL-6. Thus, this review seeks to examine the value of CRP in relation to PCT and IL-6 for the diagnosis of bacterial infections, in therapeutic monitoring, and regarding prognosis in critical care patients.

The host response to infection: advancing a novel diagnostic paradigm

Capturing the host response by using genomic technologies such as transcriptional profiling provides a new paradigm for classifying and diagnosing infectious disease and for potentially distinguishing infection from other causes of serious respiratory illness. This strategy has been used to define a blood-based RNA signature as a classifier for pandemic H1N1 influenza infection that is distinct from bacterial pneumonia and other inflammatory causes of respiratory disease. To realize the full potential of this approach as a diagnostic test will require additional independent validation of the results and studies to examine the specificity of this signature for viral versus bacterial infection or co-infection.