Procalcitonin and C-reactive protein in pericardial fluid for postmortem diagnosis of sepsis

Exploration of sepsis assisting parameters in hospital autopsied-patients: a prospective study

Although Sepsis-3 doesn't require evidence of bacteremia to diagnose sepsis, clinicians often want to identify the causative pathogen at autopsy. In principle, if the blood cultures are the same at ante- and postmortem, the cause of death is obvious. However, interpretations of postmortem blood cultures are often difficult due to discordance, negativity, mixed infection, and contamination, of pathogens occupying ≥ 50% of the tests. To increase specificity identifying agonal phase sepsis in the situations where blood cultures are discordant, multiple or negative at postmortem, we established a scoring system using blood cultures, procalcitonin (PCN) showing highest sensitivity and specificity for postmortem serum, and bone marrow polyhemophagocytosis (PHP). Histological sepsis showed significantly higher levels of culture score (2.3 ± 1.5 vs. 0.4 ± 0.5, p < 0.001), PHP score (2.5 ± 0.8 vs. 1.0 ± 1.1, p < 0.001), and PCN score (1.8 ± 0.8 vs. 0.8 ± 0.6, p < 0.01) than non-septic patients. Receiver operating characteristic curve analysis indicated that estimation of three scores was the most reliable indicator for recognizing agonal phase sepsis. These findings suggest that the combination of these three inspections enables to determine the pathological diagnoses of sepsis even it is not obvious by discordant, mixed or negative blood cultures.

Autopsy Findings and Inflammatory Markers in SARS-CoV-2: A Single-Center Experience

Purpose

The systemic inflammatory response related to COVID-19 can be easily investigated in living patients. Unfortunately, not every biomarker is suitable for postmortem analysis since several factors may interfere. The aim of this study was to summarize key histopathological findings within each organ system due to COVID-19 and to assess if serological inexpensive and widely available biomarkers such as CRP, IL-6, fibrinogen and d-Dimers, associated with adverse outcomes in COVID-19, can be implemented in a post-mortem assessment.

Patients and Methods

A total of 60 subjects divided in 2 groups were included. All subjects died outside a hospital setting and therefore did not receive specific or symptomatic therapies that could have modulated the inflammatory response. The first group included 45 subjects in which mandatory autopsy was performed in order to establish the cause of death and macroscopic examination of the lungs was highly suggestive of SARS-CoV-2 infection. As controls (Group 2), 20 subjects who died from polytrauma in high velocity car accidents and suicide were selected. Bronchial fluids collected during the autopsy procedure were used for the RT-PCR diagnosis of SARS-CoV-2 and serum samples were sent for analysis of IL-6, CRP, d-Dimers and fibrinogen.

Results

Compared with the control group, the subjects of the COVID-19 group were older (59±19.5 vs.38±19.15 years, p=0.0002) and had more underlying comorbidities such as hypertension (60% vs 35%, p=0.06) or were overweight (53.3% vs 30%, p=0.08). The levels of CRP, IL-6, fibrinogen and d-Dimers in postmortem plasma samples were significantly higher in COVID-19 subjects than in control group (p< 0.0001). Moreover, the level of IL-6 was significantly higher in overweight patients (r=0.52, P<0.001). In all COVID-19 subjects, the histological examination revealed features corresponding to the exudative and/or proliferative phases of diffuse alveolar damage. Large pulmonary emboli were observed in 7 cases. Gross cardiac enlargement with left ventricular hypertrophy was observed in 19 cases. The most frequent pathological finding of the central nervous system was acute/early-subacute infarction.

Conclusion

Due to the complexity of the inflammatory response, we postulate that a combination of biomarkers, rather than a single laboratory parameter, might be more effective in obtaining a reliable postmortem COVID-19 diagnosis.

Accuracy of Urea Nitrogen and Creatinine Measurements in Postmortem Serum and Pericardial Fluid Compared With Antemortem Data

ABSTRACT

Although several studies have measured urea nitrogen (UN) and creatinine (Cr) concentrations in postmortem serum and pericardial fluid, no recent antemortem biochemical data have been available for forensic autopsy, thereby making the evaluation of the accuracy of postmortem data difficult. This study compared antemortem (from emergency room results before the declaration of death) and postmortem serum UN and Cr concentrations, as well as postmortem serum and pericardial fluid values, in 51 forensic autopsy cases (postmortem interval within 87 hours). Postmortem UN concentrations were strongly correlated with antemortem data. Moreover, no significant difference between pericardial fluid UN concentrations and antemortem data was observed. Postmortem serum and pericardial fluid Cr values were also correlated with antemortem data, although postmortem values were significantly higher than antemortem ones. Given our observation of early postmortem elevation in Cr concentrations, such an elevation was attributed to rigor mortis. In conclusion, the current study demonstrated the utility of postmortem UN and Cr concentrations, in particular of those measured in the pericardial fluid.

Post-Mortem Investigations for the Diagnosis of Sepsis: A Review of Literature

To date, sepsis is still one of the most important causes of death due to the difficulties concerning the achievement of a correct diagnosis. As well as in a clinical context, also in a medico-legal setting the diagnosis of sepsis can reveal challenging due to the unspecificity of the signs detected during autopsies, especially when no ante-mortem clinical data, laboratory, and cultural results are available. Thus, a systematic review of literature was performed to provide an overview of the main available and updated forensic tools for the post-mortem diagnosis of sepsis. Moreover, the aim of this review was to evaluate whether a marker or a combination of markers exist, specific enough to allow a correct and definite post-mortem diagnosis. The review was conducted searching in PubMed and Scopus databases, and using variable combinations of the keywords "post mortem sepsis diagnosis", "macroscopic signs", "morphology", "histology", "immunohistochemical markers", "biochemical markers", and "forensic microbiology". The article selection was carried out following specific inclusion and exclusion criteria. A total of 44 works was identified, providing data on morphological aspects of the organs examined, histological findings, immunohistochemical and biochemical markers, and cultural assays. The review findings suggested that the post-mortem diagnosis of sepsis can be achieved by a combination of data obtained from macroscopic and microscopic analysis and microbial investigations, associated with the increased levels of at least two of three biochemical and/or immunohistochemical markers evaluated simultaneously on blood samples.

Comparison of C-reactive protein levels between antemortem serum and postmortem serum and pericardial fluid

Biochemical markers undergo postmortem changes that complicate diagnostic measurement. C-reactive protein (CRP) is one marker that is known to be useful in postmortem specimens, with high levels reported in forensic cases of sepsis, trauma, and ketoacidosis. In the present study, we included 30 cases (17 males and 13 females) that underwent forensic autopsy within 80 h of death and had a CRP result from two postmortem specimens (serum from cardiac blood and pericardial fluid) and an emergency room specimen. Antemortem results were taken at a time near to cardiopulmonary arrest and the declaration of death. CRP levels in postmortem serum and pericardial fluid correlated with those in antemortem serum. Although no significant difference was observed between the antemortem and postmortem serum levels, the pericardial level was significantly low and five false negatives were observed. We conclude that postmortem serum is suitable for use in CRP measurement, and in cases with high antemortem CRP levels, postmortem pericardial fluid may be an appropriate alternative.

Sepsis and Nosocomial Infections: The Role of Medico-Legal Experts in Italy

Sepsis is a leading cause of morbidity and mortality worldwide. It is defined as the presence of a Systemic Inflammatory Response Syndrome, and it represents a significant burden for the healthcare system. This is particularly true when it is diagnosed in the setting of nosocomial infections, which are usually a matter of concern with regard to medical liability being correlated with increasing economic costs and people's loss of trust in healthcare. Hence, the Italian governance promotes the clinical risk management with the aim of improving the quality and safety of healthcare services. In this context, the role of medico-legal experts working in a hospital setting is fundamental for performing autopsy to diagnose sepsis and link it with possible nosocomial infections. On the other hand, medico-legal experts are party to the clinical risk management assessment, and deal with malpractice cases and therefore contribute to formulating clinical guidelines and procedures for improving patient safety and healthcare providers' work practices. Due to this scenario, the authors here discuss the role of medico-legal experts in Italy, focusing on sepsis and nosocomial infections.

Presepsin: A potential superior diagnostic biomarker for the postmortem differentiation of sepsis based on the Sepsis-3 criteria

Diagnosis of sepsis-related death by autopsy is often a complex process. Presepsin (PSEP) is typically used as a marker for diagnosing sepsis after death; however, its efficacy remains unclear. In the present study, we compared the levels of PSEP, C-reactive protein (CRP), and procalcitonin (PCT) in the postmortem serum of femoral blood to determine their efficacies as biomarkers for the postmortem differentiation of sepsis. Patients (n = 93; 48 males, 45 females with a mean age: 62.8 ± 19.2 years) who were admitted to and died in hospitals were screened for sepsis based on the sequential organ failure assessment score, and those with clinically confirmed sepsis were assessed in this study. All patients underwent autopsy within 48 h (n = 44 patients) or 48-96 h (n = 49 patients) of death. The cadavers were divided into two groups using the Sepsis-3 criteria: control group (n = 74) comprising patients without clinically diagnosed sepsis, and the group of patients who were clinically diagnosed with sepsis (n = 19). The area under the curve values (AUCs) for CRP, PCT, and PSEP levels in the sepsis group were 0.83, 0.817, and 0.977, respectively, with optimal cutoff levels of 7 mg/dL (sensitivity: 78.9%, specificity: 77.0%) for CRP, 0.07 ng/mL (sensitivity: 84.2%, specificity: 68.9%) for PCT, and 1250 pg/mL (sensitivity: 100.0%, specificity: 91.9%) for PSEP. No significant differences were noted for PSEP levels for gender, age, elapsed time after death, and the presence or absence of postmortem trauma. The present study demonstrated that compared to CRP and PCT, PSEP is a superior biomarker for the postmortem differentiation of sepsis and that a concentration >1250 pg/mL is highly likely to indicate sepsis within 96 h of death. This is the first report confirming the superiority of PSEP for diagnosing sepsis after death.

A Pathophysiological Insight into Sepsis and Its Correlation with Postmortem Diagnosis

BACKGROUND

Sepsis is among the leading causes of death worldwide and is the focus of a great deal of attention from policymakers and caregivers. However, sepsis poses significant challenges from a clinical point of view regarding its early detection and the best organization of sepsis care. Furthermore, we do not yet have reliable tools for measuring the incidence of sepsis. Methods based on analyses of insurance claims are unreliable, and postmortem diagnosis is still challenging since autopsy findings are often nonspecific.

AIM

The objective of this review is to assess the state of our knowledge of the molecular and biohumoral mechanisms of sepsis and to correlate them with our postmortem diagnosis ability.

CONCLUSION

The diagnosis of sepsis-related deaths is an illustrative example of the reciprocal value of autopsy both for clinicians and for pathologists. A complete methodological approach, integrating clinical data by means of autopsy and histological and laboratory findings aiming to identify and demonstrate the host response to infectious insults, is mandatory to illuminate the exact cause of death. This would help clinicians to compare pre- and postmortem findings and to reliably measure the incidence of sepsis.

Bacterial Translocation and Sample Contamination in Postmortem Microbiological Analyses

The diagnostic value of postmortem bacteriology has been discussed controversially for decades. In the study herein, contamination during sampling procedures and postmortem translocation were investigated to interpret postmortem microbiology results. One hundred medicolegal autopsy cases in total were included. Radiology, histology, bacteriology, and biochemistry were performed in all cases. Based on all investigation findings, 4 groups of cases were identified: death unrelated to infection, true infections, false positive (contamination during sampling procedures, postmortem translocation and mixed situations), and undetermined. The results of this study indicate that postmortem bacteriology provides useful data supporting infection-related deaths, especially when potentially significant observations are accompanied by consistent autopsy, histology, and biochemistry. Result interpretation requires careful evaluation of number and type of isolated microorganisms.

Evaluation of procalcitonin postmortem levels in some models of death: An experimental study

Post-mortem determination of biochemical parameters, especially for obscure cases, has been recognized useful in diagnosis of the underlying causes of death. Procalcitonin (PCT) is known to rise in a response to any proinflammatory stimulus. The present study aims to estimate postmortem PCT levels in serum and kidney, liver, brain; and whether it is similar in different causes of death models (trauma, drowning and freezing) models or not. The study was performed on 60 male rabbits. Rabbits were divided into four different death induced models (15 rabbit each): trauma, infection, drowning and freezing models. At the end of the study, all rabbits were sacrificed; blood samples, kidneys, livers and brains were collected. PCT was measured using ELISA assay. Results showed highly significant increase in PCT levels in all tested samples in different models of death. The infection induced model showed the highest levels in all tested samples compared to other groups mainly in liver; followed by trauma model and drowning model which were increased mainly in brain's samples. The least model which showed increased PCT levels was the freezing model mainly in liver samples. Post Hoc multiple comparisons test showed significant differences between groups in most of liver, brain and kidney samples, while PCT serum blood samples were significant only between trauma and infection groups. It was concluded that PCT can differentiate between sepsis and non-sepsis related deaths and that organs like liver, kidney and brain PCT levels could be an alternative to serum PCT for the diagnosis of postmortem sepsis.

Cerebrospinal fluid PCR analysis and biochemistry in bodies with severe decomposition

The aim of this study was to assess whether Neisseria meningitidis, Listeria monocytogenes, Streptococcus pneumoniae and Haemophilus influenzae can be identified using the polymerase chain reaction technique in the cerebrospinal fluid of severely decomposed bodies with known, noninfectious causes of death or whether postmortem changes can lead to false positive results and thus erroneous diagnostic information. Biochemical investigations, postmortem bacteriology and real-time polymerase chain reaction analysis in cerebrospinal fluid were performed in a series of medico-legal autopsies that included noninfectious causes of death with decomposition, bacterial meningitis without decomposition, bacterial meningitis with decomposition, low respiratory tract infections with decomposition and abdominal infections with decomposition. In noninfectious causes of death with decomposition, postmortem investigations failed to reveal results consistent with generalized inflammation or bacterial infections at the time of death. Real-time polymerase chain reaction analysis in cerebrospinal fluid did not identify the studied bacteria in any of these cases. The results of this study highlight the usefulness of molecular approaches in bacteriology as well as the use of alternative biological samples in postmortem biochemistry in order to obtain suitable information even in corpses with severe decompositional changes.

Markers for sepsis diagnosis in the forensic setting: state of the art

Reliable diagnoses of sepsis remain challenging in forensic pathology routine despite improved methods of sample collection and extensive biochemical and immunohistochemical investigations. Macroscopic findings may be elusive and have an infectious or non-infectious origin. Blood culture results can be difficult to interpret due to postmortem contamination or bacterial translocation. Lastly, peripheral and cardiac blood may be unavailable during autopsy. Procalcitonin, C-reactive protein, and interleukin-6 can be measured in biological fluids collected during autopsy and may be used as in clinical practice for diagnostic purposes. However, concentrations of these parameters may be increased due to etiologies other than bacterial infections, indicating that a combination of biomarkers could more effectively discriminate non-infectious from infectious inflammations. In this article, we propose a review of the literature pertaining to the diagnostic performance of classical and novel biomarkers of inflammation and bacterial infection in the forensic setting.

Procalcitonin as a postmortem sepsis marker. A comparison of the validity of results obtained from blood serum, aqueous humour and cerebrospinal fluid

In recent years, serum levels of the prohormone procalcitonin have been investigated in a number of studies in relation to postmortem sepsis diagnostics, as macroscopic and histomorphological findings are, as a rule, nonspecific. However, due to advanced haemolysis, it is often not possible to determine serum procalcitonin (PCT) levels in cases of sepsis-related death. Moreover, the impact of postmortem interval on PCT levels is largely unclarified. In view of this, the present pilot study investigated PCT levels in the serum, aqueous humour, and cerebrospinal fluid in a study population of 25 persons who died of sepsis and a control population of 25 deaths unrelated to sepsis. Using the Mann-Whitney U test, statistically significant differences in PCT levels were determined for all the analysed samples from the study and control populations. Logistic regression analysis was used to calculate cut-off values for sepsis diagnosis for all the sample types. Furthermore, the serum elimination rates published by Tsokos et al. (Int J Legal Med 114:237-243, 2001) were used to calculate the PCT levels at the time of death for the cases with a known postmortem interval. The results of our study demonstrate that, taking account of the postmortem elimination process, it is possible to infer the value at the time of death from the procalcitonin levels measured in all three sample types and to interpret this with the aid of a defined cut-off value. The findings need to be verified based on a larger study population.