Abstract
This article describes the utility of postmortem CT and MRI in diagnosing pediatric bowel obstruction (BO) as the cause of septic shock-induced death. Six pediatric cases with confirmed septic shock were retrospectively analyzed. Postmortem CT scans revealed clear signs of BO in all cases, with volvulus, intussusception, diaphragmatic hernia, or Meckel's diverticulum identified. MRI scans, performed in three cases, did not provide additional diagnostic information. The presented case series highlights the potential of postmortem CT for diagnosing BO in children, potentially aiding in understanding the cause and manner of death. While MRI offered limited additional benefits, its role in conjunction with CT and autopsy warrants further exploration. Combining these modalities could enhance diagnostic accuracy and provide a more complete picture of the cause of death in children.
Introduction
Mechanical bowel obstruction (BO) accounts for 15% of all hospital admissions for acute abdominal pain and leads to more than 300,000 hospitalizations and approximately 28,000 deaths annually in the United States.1,2 Since the physical examination, clinical presentation, and laboratory findings of these patients are often nonspecific and nondiagnostic, the clinical diagnosis of BO remains difficult. 1 Radiological imaging, in particular computed tomography (CT), can play a decisive role in the diagnosis of BO, as it is able to show specific radiological signs suggestive of BO.1,2 For instance, CT can effectively visualize the characteristic “whirl” (or “whirlpool”) sign associated with volvulus and the “doughnut” (or “target”) sign indicative of intussusception, thanks to its ability to generate multiplanar reconstructions from its three-dimensional dataset.1–3 Failure to timely diagnose and treat BO can lead to fatal consequences. This occurs due to a cascade of events initiated by the obstruction itself. Dilation of the bowel segments proximal to the blockage accumulates gas and fluid, significantly raising intraluminal pressure. This rise in pressure, coupled with impaired intestinal motility caused by the obstruction, creates an environment conducive to bacterial overgrowth. This overgrowth potentiates translocation of bacteria and their endotoxins across the compromised intestinal barrier, leading to inflammation in the mesenteric lymph nodes and potentially entering the systemic circulation, which can ultimately progress to sepsis and multi-organ failure, culminating in death due to septic shock. 1 Bowel perforation secondary to necrosis at the obstruction site considerably amplifies mortality risk in the absence of timely intervention. 2
Septic shock due to BO can be a cause of death encountered in forensic investigations. In such cases, postmortem CT, an increasingly utilized tool in forensic pathology, can effectively identify and localize the obstruction. Employing postmortem CT scans, Gascho et al. 4 offered forensic support for diagnoses of BO, demonstrating consistency with both autopsy findings and the documented cause of death (septic shock) on death certificates. Their results suggested that postmortem CT performed within 3 days of death could be a valuable tool for identifying BO. Beyond three days, gas formation during decomposition increasingly obscures specific signs, making them indistinguishable from normal postmortem changes. For instance, marked bowel dilatation, a hallmark of BO, can mimic a normal finding that occurs in the course of decomposition. 4 While Gascho et al. 4 demonstrated the potential of postmortem CT for adult BO identification, the diagnostic utility of CT in pediatric BO merits exploration. The diagnostic utility of postmortem CT for the detection of pediatric bowel obstruction may differ from that in adults due to the following considerations: First, pediatric bowel obstruction exhibits a distinct etiological profile compared to adults, encompassing both congenital and acquired factors. 5 Second, CT provides reduced soft tissue contrast in pediatric cases, rendering magnetic resonance imaging (MRI) the preferred modality for comprehensive pathological assessment in childhood deaths.6,7 Third, the differences in the rate of decomposition between adults and children may narrow the postmortem time window of 3 days. 8
In this case series, we focused on postmortem CT and MRI scans of forensic pediatric cases that died of septic shock to assess the diagnostic utility of these imaging modalities for the detection of pediatric BO.
Materials and methods
This case series included six pediatric cases (4 males, 2 females, median age: 21.5 months; range: 3–56 months) where septic shock was confirmed as the cause of death via microbiological testing. The judicial death investigation encompassed postmortem imaging, autopsy and laboratory analyses. Postmortem 128-slice CT scans were performed on all six individuals within three days of death. Three of these individuals also underwent 3 Tesla MRI scans. The scan protocols followed recommendations from the literature.6,9 A board-certified radiologist retrospectively reviewed all CT scans, focusing on specific abdominal findings potentially associated with BO. As part of the forensic medical service and supporting legal inquiries, the scientific investigation met ethical standards and secured a no-objection declaration from the competent ethics committee.
The case histories are described briefly in the following:
Results
Table 1 summarizes the diagnoses and supporting findings identified in all six cases. Postmortem CT scans revealed clear signs of bowel obstruction (BO) in each individual. The specific cause of BO varied, with volvulus identified in two cases (see Figure 1), intussusception in two others, and diaphragmatic hernia or Meckel's diverticulum in the remaining two. Importantly, all findings listed in Table 1 were confirmed by CT alone; the additional MRI examinations conducted in three cases did not reveal further information but served to corroborate the CT assessments. Notably, the CT findings align with the diagnoses recorded on the death certificates.
Postmortem whole-body imaging of a 3-month-old male infant (Case 1). A: The three-dimensional CT reconstruction generated using the cinematic rendering technique (CRT) suggests a mild dilatation of the bowel. B: The cross-sectional CT images, acquired with a soft kernel for soft tissue diagnostics, demonstrate a volvulus through the “whirl” sign. C and D: The “whirl” sign is also clearly visible on T1- and T2-weighted MRI.
Diagnostic findings and diagnoses.
The findings of the autopsy and the microbiological analysis, which were not collected as part of this case study but earlier as part of the routine case work, are summarized in the following. Autopsies with prior post-mortem imaging information confirmed the findings identified during the retrospective analysis of image data summarized in Table 1. However, the autopsies revealed also additional organ findings indicative of a shock state, such as pale renal cortex contrasting with dark red renal medulla. Microbiological analysis of blood cultures, spleen smears, liver smears, and, in individual cases, additionally of smears from other organs yielded positive results for (in alphabetical order): gram-positive cocci, Staphylococcus epidermidis, Staphylococcus lugdunensis, Streptococcus pyogenes, Streptococcus salivarius, and Weissella confusa.
Discussion
In all six deaths, imaging examinations identified the likely source of infection leading to septic shock, which was ultimately fatal. While MRI did not show additional benefits in identifying obstructions in the presented cases, its unique capacity for visualizing soft tissues warrants continued consideration alongside CT, especially in pediatric cases. The extent to which a postmortem imaging may support the determination of bowel obstruction should be discussed under two different vintage points, namely imaging as supplement to autopsy and postmortem imaging as alternative to autopsy.
Although signs of BO, such as necrotic tissue or twisted intestinal loops, are usually found at autopsy, a prior CT scan may still enhance understanding in these cases. This non-invasive imaging tool can unveil crucial details such as the precise location and extent of the obstruction, underlying conditions contributing to it, and potential complications like perforation or ischemia. By providing such imaging findings, the CT scan complements the autopsy findings and may lead to a more precise understanding of the individual case and a more complete picture of the cause of death. The diagnosis of an intestinal obstruction on CT is already an indication of possible sepsis leading to death, and the appropriate sampling and swabbing of the organs can be planned for the autopsy. 4 Whether the forensic pathologists would have detected the bowel obstructions without prior imaging in our pediatric cases cannot be assessed, as they were informed about radiologic findings, but we do not even consider this comparison between autopsy and postmortem imaging to be material. While postmortem CT has seen extensive use for two decades, the new gold standard is considered to be a combined approach: autopsy in conjunction with postmortem CT imaging, leveraging the strengths of both modalities, although autopsy remains the primary component of this approach. 10 This strongly suggests that performing postmortem imaging in conjunction with autopsy enhances the accuracy of a death investigation, even though limitations due to logistical complexities and additional costs exist for many institutions. 11 Leveraging the increased availability of CT scanners in hospitals opens doors for more frequent postmortem imaging, especially for children whose transportability eases logistical challenges. 12 While our case series on pediatric bowel obstruction (BO) did not find significant additional benefits of MRI compared to CT, we recommend considering both modalities in conjunction with autopsy for pediatric postmortem examinations. The unparalleled capabilities of MRI in soft tissue visualization can offer complementary information, particularly in pediatric cases. 13 The wide range of T1, T2, and diffusion-weighted sequences available in MRI allows for comprehensive anatomic delineation of the soft tissue structures and the detection of pathologic and trauma-related changes in these structures that may not be detectable with CT. In addition, some trauma-related MRI findings can be interpreted more accurately with the information from an additional CT scan, for instance to reliably distinguish between blood and air in standard MRI sequences. 14
Postmortem imaging without subsequent autopsy can be seen as an extension of external examination to more reliably exclude an unnatural cause of death. We prefer the term “extension of external examination” over “alternative to autopsy” because “alternative” falsely suggests equality in diagnostic accuracy and undermines the complementary value of imaging to external examination. In cases where a criminal offense is highly unlikely or when there is a low need to further clarify the course of an accident, an autopsy may be waived. In such cases, a CT scan can provide certainty that death was natural, for example by diagnosing a cerebral hemorrhage, cardiac tamponade, or BO, allowing for the assumption of septic shock as the cause of death. For definitive confirmation of sepsis, minimally invasive biopsies can be employed to collect organ samples that undergo subsequent microbiological testing. When autopsy is not performed, postmortem imaging can play an important role in unexplained pediatric deaths. 15 This is especially true when families do not want the child's body to be opened, as postmortem imaging offers a way to learn more about the cause of death. 16 While this is probably more relevant to pathological investigations than forensic investigation, both fields face a shared challenge: the decline in autopsy rates. A desire for postmortem imaging without subsequent autopsy likely stems from the declining number of autopsies, particularly in cases where neither accident nor crime are suspected, but rather suicide or natural internal events. In such cases, postmortem imaging plays an increasingly valuable role, providing additional information beyond what external examination can offer. Therefore, postmortem imaging can truly serve as a valuable extension to external examination, when an autopsy is waived, offering additional insights into the body.
Given that a post-mortem skeletal survey is recommended to exclude skeletal trauma in unexplained infant deaths, 17 and on the assumption that for many institutions this examination is easier to perform than a CT scan, it is worth noting two-dimensional radiographs can also reveal signs of BO. Like CT reconstructions, plain radiographs can show dilated intestinal loops with gas-fluid levels, along with specific signs like the “coffee bean sign” (a dilated colon loop resembling a coffee bean) and the “Frimann-Dahl sign” (three converging dense lines: two outer walls and a central inner wall, pointing towards the pelvis). 18
Conclusion
This article confirms postmortem CT as a valid tool for diagnosing pediatric bowel obstructions. Whether additional MRI can play a beneficial role in these cases still needs to be researched. Leveraging the strengths of CT and MRI alongside autopsy holds promise for enhanced diagnostic accuracy, and ultimately, better understanding of cause and manner of death in children.
Footnotes
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
