Histologic dating of bruises in moribund infants and young children

State-of-the-Art on Wound Vitality Evaluation: A Systematic Review

The vitality demonstration refers to determining if an injury has been caused ante- or post-mortem, while wound age means to evaluate how long a subject has survived after the infliction of an injury. Histology alone is not enough to prove the vitality of a lesion. Recently, immunohistochemistry, biochemistry, and molecular biology have been introduced in the field of lesions vitality and age demonstration. The study was conducted according to the preferred reporting items for systematic review (PRISMA) protocol. The search terms were "wound", "lesion", "vitality", "evaluation", "immunohistochemistry", "proteins", "electrolytes", "mRNAs", and "miRNAs" in the title, abstract, and keywords. This evaluation left 137 scientific papers. This review aimed to collect all the knowledge on vital wound demonstration and provide a temporal distribution of the methods currently available, in order to determine the age of lesions, thus helping forensic pathologists in finding a way through the tangled jungle of wound vitality evaluation.

Traumatic Epidural and Subdural Hematoma: Epidemiology, Outcome, and Dating

Epidural hematomas (EDHs) and subdural hematomas (SDHs), or so-called extra-axial bleedings, are common clinical entities after a traumatic brain injury (TBI). A forensic pathologist often analyzes cases of traumatic EDHs or SDHs due to road accidents, suicides, homicides, assaults, domestic or on-the-job accidents, and even in a medical responsibility scenario. The aim of this review is to give an overview of the published data in the medical literature, useful to forensic pathologists. We mainly focused on the data from the last 15 years, and considered the most updated protocols and diagnostic-therapeutic tools. This study reviews the epidemiology, outcome, and dating of extra-axial hematomas in the adult population; studies on the controversial interdural hematoma are also included.

Optimising the sampling procedure for forensic investigation of bruises on pigs

BACKGROUND

Human-inflicted bruises on pigs are a violation of the law and affected tissue is regularly sent for forensic investigation. The authors aimed to evaluate the variation in inflammation within and between human-inflicted porcine bruises in order to determine the optimal sampling procedure.

METHODS

Skin and muscle tissues from the centre and ends of 21 bruises were evaluated histologically. Moreover, RNA was extracted from the subcutaneous fat tissue. The bruises were detected during meat inspection at the slaughter line, and all carcases were kept at 5°C for 12-24 hours before sampling.

RESULTS

The sampling site with the most infiltration of neutrophils and macrophages differed between bruises inflicted on the same pig and between bruises inflicted on more pigs within the same delivery. The extracted RNA had RIN (RNA integrity number) values from 3 to 6.5.

CONCLUSIONS

Tissue samples should always be taken from both skin and underlying muscle tissue. Samples should be collected from several sites along each bruise, and all bruises should be sampled in order to include the site of maximum tissue damage and inflammation. Moreover, RNA of sufficient quality for quantitative PCR and subsequent age estimation cannot be obtained from carcases kept for 12-24 hours at 5°C.

Histopathologic Analysis in Sudden Infant and Child Deaths: A Practical Approach

The forensic pathologist responsible for sudden unexpected death (SUD) investigation in the pediatric setting faces many challenges. It usually takes many years to obtain reasonable experience and exposure to the wide variety of diseases that may present as SUD in a pediatric context, and to appreciate the differences in the etiology and clinical context between the pediatric and adult SUD setting. In pediatric SUD, it is necessary to conduct a systematic, pediatric-focused autopsy investigation including extensive histopathological assessment and ancillary testing. Postmortem histologic findings in the context of SUD in the pediatric population are often subtle and distinctly different from those seen in the adult population. The pathologist must have an understanding of both developmental and pathological processes in order to correctly interpret the findings during a pediatric autopsy. A system-based, histopathology-focused review of common entities, normal variants, and incidental findings that can prove challenging will be discussed. For the forensic pathologist tasked with pediatric SUD autopsies, development of a strong collaborative relationship with a pediatric pathologist and/or neuropathologist to assist with histopathological analysis is strongly endorsed.

The intensity of the inflammatory response in experimental porcine bruises depends on time, anatomical location and sampling site

The assessment of the age of bruises inflicted on livestock is an important component of veterinary forensic pathology investigations. However, the sampling site within a bruise, the anatomical location and the mass and speed of the object inflicting the blunt trauma might influence the intensity of the inflammatory reaction. In the present study, the variation of the inflammatory reaction within and along experimental porcine bruises was evaluated in order to determine the optimal sampling site. Moreover, we evaluated if a combination of histological characteristics and gene expression signatures was able to differentiate bruises according to anatomical location, age of bruises and the speed and mass of the object used to cause the impact. Twelve experimental slaughter pigs were anesthetized, and on each animal four blunt traumas were inflicted on the back using either a plastic tube or an iron bar, respectively. The pigs were euthanized at 2, 5 or 8 h after infliction. Following gross examination, skin and underlying muscle tissue were sampled from the center and both ends of bruises and evaluated histologically. Subcutaneous fat tissue from the center of the bruises was sampled for quantitative real-time polymerase chain reaction to evaluate mRNA expression of 13 selected genes. Uninjured tissue was sampled from the right thigh of all pigs and served as control tissue. The amount of tissue damage and the intensity of the inflammatory reaction in bruises depended on the sampling site within and along a bruise, the anatomical location and the age of the bruise. The optimal site for sampling, i.e. the most pronounced inflammatory reaction, was at the center of the bruises where the plastic tube or iron bar first struck the skin. Moreover, bruises inflicted in areas with a thin layer of subcutaneous fat tissue showed more damage and inflammation in the underlying muscle tissue compared to bruises inflicted in areas with a thicker layer of subcutaneous fat tissue. In addition, hemorrhage in the muscle tissue was more likely present when bruises were inflicted with an iron bar compared to a plastic tube. Combining histology and mRNA expression of the 13 genes showed that the age of bruises could be determined with a precision of ±2.04 h. Moreover, the age of bruises could be determined with a precision of ±1.84 h based solely on mRNA expression of a selection of four genes.

Forensic aspects of gene expression signatures for age determination in bruises as evaluated in an experimental porcine model

Determining the age of bruises and the force used to inflict the trauma is of crucial importance in both human and veterinary forensic pathology. In the present study, the expression of more than 50 different genes in subcutaneous fat and muscle tissue from experimental bruises in pigs was investigated. The aim was to evaluate if expression signatures of selected genes were capable of determining bruises according to age and the force of impact. Eighteen experimental pigs were anesthetized, and on each animal four blunt traumas were inflicted on the back with a low, moderate or high force. The pigs were euthanized from 1 to 10 h after infliction of the trauma and subcutaneous fat and muscle tissues were sampled. As control, subcutaneous fat and muscle tissues were sampled from two un-injured pigs. Quantitative real-time polymerase chain reaction was performed to evaluate mRNA expression of genes involved in inflammation, tissue damage and repair. Expression signatures of thirteen selected genes in subcutaneous fat but not in muscle tissue reflected the age of bruises with a precision of approximately ±2 h. Moreover, the gene expression signature in the subcutaneous fat was to some extend able to separate bruises inflicted with different forces. Expression signatures of selected genes in the subcutaneous fat will increase the precision of the age determination of bruises in pigs. Further, due to the similarity of porcine and human skin physiology and immunity, these results might also provide valuable information in human forensic science.

Gross and histopathological evaluation of human inflicted bruises in Danish slaughter pigs

Background

Human inflicted bruises in slaughter pigs are hampering animal welfare, are an infringement of the animal protection act, and are a focus of public attention. The aim of the present study was to evaluate the gross appearance of human inflicted bruises in slaughter pigs and to compare the inflammatory changes in two lesions as a basis for estimating the age of lesions in the same pig.

Pigs with human inflicted bruises slaughtered at two major slaughterhouses in Denmark from November 2013 to May 2014 were evaluated. After slaughter, the bruises were examined grossly and skin and underlying muscle tissue from two similar but separate bruises (a and b) on each pig were sampled for histology.

Results

Skin and muscle tissue from 101 slaughter pigs were subjected to gross evaluation. Eighty-one of these were also subjected to histological evaluation. Most frequently (51 out of 101 pigs, 50 %), bruises had a tram-line pattern due to blunt trauma inflicted with long objects such as sticks. Other bruises reflected the use of tattoo-hammers, plastic paddles, double U profiles and chains. Histological evaluation of two bruises from a pig with multiple lesions was found insufficient to assess the overall age of the lesions as substantial variation in the inflammatory response between bruises was present.

Conclusions

Grossly, the pattern of bruises often reflected the shape of the object used for inflicting the lesions. When determining the age of multiple bruises on a pig more than two lesions should be evaluated histologically.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-016-0869-3) contains supplementary material, which is available to authorized users.

Vascular lesions simulating bruising

Careful examination of the skin and soft tissues is a routine part of the forensic autopsy to identify and characterise traumatic lesions. Three cases are reported where benign vascular lesions presented as bruises. In case 1, a 44-year-old man with a history of epilepsy was found dead on the floor. Dissection of the neck revealed a haemorrhagic area 15 mm × 1.5 mm, deep to the left thyrohyoid muscle. In case 2, an 87-year-old man was found dead with a plastic bag over his head attached to an opened cylinder of nitrogen gas. On the mucosal surface of his upper lip, there was an apparent 5 mm blue/purple bruise. In case 3, examination of the back of a 16-month-old girl revealed an apparent 15 mm bruise. Histological examination of all three lesions revealed benign vascular lesions. In the absence of microscopy, these lesions would have been considered traumatic in origin, raising the possibility of inflicted trauma.

A novel, comprehensive, and reproducible porcine model for determining the timing of bruises in forensic pathology

PURPOSE

Calculating the timing of bruises is crucial in forensic pathology but is a challenging discipline in both human and veterinary medicine. A mechanical device for inflicting bruises in pigs was developed and validated, and the pathological reactions in the bruises were studied over time in order to identify gross and histological parameters that may be useful in determining the age of a bruise.

METHODS

The mechanical device was able to apply a single reproducible stroke with a plastic tube that was equivalent to being struck by a man. In each of 10 anesthetized pigs, four strokes that resulted in bruises were inflicted on the back. In addition, 2 control pigs were included in the study. The pigs were euthanized consecutively from 1 to 10 h after the infliction of bruises. Following gross evaluation, skin, and muscle tissues were sampled for histology.

RESULTS

Grossly, the bruises appeared uniform and identical to the tramline bruises seen in humans and pigs subjected to blunt trauma. Histologically, the number of neutrophils in the subcutis, the number of macrophages in the muscle tissue, and the localization of neutrophils and macrophages in muscle tissue showed a time-dependent response. Combining these parameters, bruises could be grouped as being either less than 4 h old or between 4 and 10 h of age. Gross lesions and changes in the epidermis and dermis were inconclusive with respect to time determination.

CONCLUSIONS

The model was reproducible and resembled forensic cases of bruises in pigs and humans. Therefore, the histological parameters are suitable for age determination of bruises in pigs and likely also in humans.

Delayed splenic rupture: dating the sub-capsular hemorrhage as a useful task to evaluate causal relationships with trauma

The aim of the paper was to perform a chronological assessment of the phenomenon of delayed rupture of the spleen, to assess the phenomenological order about the sub-capsular hematoma transformation to determine the causal relationship with trauma as hypothetical cause of death. 80 cases of blunt trauma with splenic capsular hematoma and subsequent rupture of the spleen were evaluated: 38 had an acute rupture of the spleen, 42 presented a break in days or weeks after the traumatic injury. Time between the traumatic event and delayed rupture of the spleen is within a range of time from one day to more than one month. Data recorded included age, sex, type of trauma, injury severity score, grade of splenic injury, associated intra-abdominal injuries, pathologic specimen evaluation. Immunohistochemical investigation of perisplenic hematoma or laceration was performed utilizing polyclonal antibodies anti-fibrinogen, CD61 and CD68, and showed structural chronological differences of sub-capsular hematoma. Expression of modification and organization of erythrocytes, fibrinogen, platelets and macrophages provides an informative picture of the progression of reparative phenomena associated with sub-capsular hematoma and subsequent delayed splenic rupture. Sub-capsular splenic hematoma dating, which we divided into 4 phases, is representing a task in both clinical practice and forensic pathology.

Does the intensity of the inflammatory reaction in a bruise depend on its proximity to the site of trauma?

Whole blood was withdrawn by tail vessel puncture from anesthetized adult male Sprague-Dawley rats and 0.1 ml was re-injected subcutaneously at each of two sites on their abdominal wall. In addition, two adjacent sites were injected with 0.1 ml of sterile saline, and two more sites were only punctured using an injecting needle. In the second part of the study anesthetized adult male Sprague-Dawley rats had two sites on the abdominal wall pinched using a small pair of forceps, two adjacent sites received an injection of 0.1 ml of whole blood obtained by tail vessel puncture, and two more sites were both pinched and injected with 0.1 ml of whole blood. At intervals of 3, 6, 12 h, 1, 2, 3, 5, and 7 days the animals were euthanized and the skin of the abdomen was processed for histological assessment. Hemosiderin staining in tissues from the first part of the study was assessed qualitatively by scoring sections as 0, 1, 2, or 3 (representing no staining, mild staining, moderate staining, and intense staining) and semi quantitatively using a Nanozoomer Digital Pathology Scanner (NDP Scan U10074-01, Hamamatsu Photonics K.K., Japan). No inflammatory reaction was observed at the sites subjected to needle puncture only. At the sites of saline injection a mild reaction occurred. At the sites where the blood had been injected an intense inflammatory cell response occurred centrally, but not toward the periphery where blood had tracked. In the second experiment the most intense inflammation was also observed in the sites where there had been a pinch and injection of blood. Again, this was maximal centrally with reduced inflammation peripherally. Perls' staining of hemosiderin was comparable in both models, with iron first observed at day 1 at the region of the injection site. At the sites of injection only, and the sites of injection plus pinch, blood had spread laterally. Hemosiderin staining appeared first and more intensely at the site of injection/trauma. The intensity of the inflammatory response in this animal model of bruising was, therefore, directly related to the proximity to the site of trauma; the appearance and intensity of hemosiderin staining was also influenced by the location within the bruises. This study has shown that histological changes that may be utilized to date bruises may be significantly influenced by the site of the biopsy.

Magnetic resonance imaging (MRI) of bruises: a pilot study

The purpose of this study was to investigate if magnetic resonance imaging (MRI) could be used to image the presence of hemosiderin in bruises and if there was the potential for this technique to be applied as a non-invasive method to estimate the age of bruises. To achieve this aim an animal model to produce lesions resembling bruises was created by injecting blood obtained from the tail vein subcutaneously into an area of the abdominal wall. The animals were euthanized at 3, 6, 12 h, 1, 2, 3, 5, and 7 days post injection and the skin of the abdominal wall was excised for MRI scanning and histological examination. The injected blood appeared as hypointense (dark) areas on the T2* MRI at 3 and 6 h. The image of the injected areas became indistinct at 12 h and continued to be indistinct at 1 and 2 days, although there appeared to be transitioning from hypointensity to hyperintensity (light). The magnetic resonance image appeared to better correspond to the histological appearance at 3 and 5 days, with the "bruise" appearing hyperintense (white); however, some hypointense (darker) areas at 3 day possibly corresponded to the development of hemosiderin. At 7 day the injected blood had been converted to hemosiderin with possible correlation between areas of blue staining in Perls' stained histologic sections and areas of extreme hypointensity in the T2* magnetic resonance image. This study has shown that a series of changes occur on MRI of bruises in an animal model that may relate to histological changes. Although variability in the intensity of the MRI signal and considerable soft tissue artifact currently make interpretations difficult, this may be a technique worth pursuing in the non-invasive evaluation of bruises.