Autopsy is a valuable procedure performed by a qualified physician to assess the quality of patient care to evaluate clinical diagnostic accuracy. In addition, autopsy determines the effectiveness and impact of therapeutic regimens in discovering and defining new or changing diseases to increase the understanding of biological processes of disease. It also helps in augmenting clinical and basic research, to provide accurate public health and education as it relates to disease and medico - legal factual information. The benefits of forensic autopsy in criminology are undisputed; it allows the pathologist to see, and describe findings that were previously demonstrated and confirmed through the use of histology for confirmation (Dolinak, Lew & Matshes 2005).
In practice, there is abundant evidence that clinical diagnosis still have room for improvement and that autopsy has much to contribute to the improvement of patient care. However, forensic pathology requires extensive understanding on post-mortem and ante-mortem differences for accurate reporting of post-mortem examinations. Therefore, this paper will provide comparisons between ante-mortem and post-mortem injuries. It will also attempt to demystify the criticism surrounding autopsy (post-mortem) by evaluating the drawbacks associated to all the methods applied in the assessment of bruises.
Ante-mortem and Post-mortem
Post-mortem refers to a forensic investigation of the cause of death, and it is done after the occurrence of the death. Ideally, post-mortem examination results are based on the form of injuries detected. In practice, there are two types of injuries involved in forensic pathology; ante-mortem injuries and post-mortem injuries. Ante-mortem injuries occur before death whereas post-mortem injuries occur after death. Therefore, ante-mortem refers to events occurring prior to death.
Comparison of Ante-mortem and Post-mortem Injuries
Ordinarily, the nature of injuries is used as the principal factor for differentiating ante-mortem injuries from post-mortem injuries. Therefore, comparison between ante-mortem and post-mortem injuries can be established with the use of the appearances of the bruise or wound.
In ante-mortem injuries, haemorrhage is associated with clotting in which clots are laminated, firm and variegated (Greaves 2000). Haemorrhage is characterized with copious amounts from arterial vessels (Bardale 2011). Post-mortem slight haemorrhage occurs on the venous vessels in which clots are absent, or they are soft, non-laminated with friable chicken-fat (yellow) appearance (Vanezis 2001).
In addition, ante-mortem wound edges appear gaped, averted and swollen whereas post-mortem wound edges are apposed without swellings.
On the other hand, the interpretation of bruises serves as a principal approach for the differentiation of ante-mortem and post-mortem injuries. Ordinarily, the appearance of bruises is indicative of the cause and time when the bruise occurred. However, it is worth noting that the location of the bruise is considered quite useful in forensic examinations. Some body parts are more likely to sustain bruises than others. For instance, bruises are known to occur more readily where there is a loose tissue such as eyebrows or subcutaneous fat than in areas where a tissue is strongly supported. In addition, the nature of the surface and force involved determines the intensity, shape, pattern and the size of the resultant bruise (Vanezis 2001). Therefore, it is quite easy to determine the nature of object used in causing the injury although there are other factors for consideration.
In general, ante-mortem bruises can be differentiated from post-mortem bruises by the use of the principal characteristics observed in histological aging. Ideally, histological ageing is used in dating ante-mortem bruises. Bruises undergo histological changes from the date of occurrence to healing. Shortly after the occurrence of a bruise, inflammation occurs in which haemostatic and vascular response occurs. This takes place within one to three days after injury. The second phase includes the regeneration of connective and epithelial tissues which occurs up to 14 days whereas scar formation results after several months (Vanezis 2001). Therefore, these changes aid in differentiating ante-mortem from post-mortem bruises. In practice, ante-mortem bruises manifest any of these characteristics, but post-mortem bruises do not show all these features because dead cells do not undergo such biological processes.
Some of the most reliable methods applied in distinguishing ante-mortem from post-mortem injuries include enzyme histochemistry, microscopy and serology. Other methods used in the assessment of bruises are direct gross examination of the dead body, objective colour assessment and gross naked eye and photographic assessment.
Enzyme histochemistry involves the quantification of various enzymes in the body to determine the time when the bruise occurred. Ordinarily, enzyme histochemistry for ante-mortem injuries shows positive and negative vital reactions. In contrast, vital reactions are absent in post-mortem injuries (Bardale 2011). Another significant biochemical diagnostic approach for distinguishing ante-mortem from post-mortem injuries is the quantification of Leukotriene B4 (LTB4) with HPLC. In practice, Leukotriene B4 is present in ante-mortem injuries, but it is absent in post-mortem injuries (He & Zhu 1996).
Despite the benefits related to biochemical assessment of injuries, it encompasses several drawbacks. For instance, decomposition of the body causes degradation of some of the most reliable enzymes contained in haemoglobin and this may lead to misinterpretation of the bruise (Vanezis 2001). In addition, serotonin and histamine which are the principal components assayed during biochemical assessment degrade upon the putrefaction of the victim’s body.
On the other hand, microscopy for ante-mortem injuries show RBC and leukocyte infiltration within muscle fibres in which platelets are present. In post-mortem injuries, microscopy does not show RBC infiltration or platelets presence in clots, and serology does not indicate an increase of histamine and serotonin content (Waters 2010).
In most cases, microscopic examination is based on determining the presence of haemosiderin in the body. Ordinarily, haemosiderin is produced in the body, shortly after death. However, haemosiderin deposits appear in different body organs in variable time intervals (Akgoz, Eren, Fedakar & Turkmen 2008). For instance, haemosiderin occurs in subcutaneous tissue in 24-48 hours after injury while its appearance in the brain takes 4 days (Vanezis 2001).
Therefore, this temporal differences compromise the accuracy of microscopic assessment; thus, presenting difficulties in differentiating ante-mortem injuries from post-mortem injuries.
- Quote paper
- Patrick Kimuyu (Author), 2017, The differences between postmortem and antemortem injuries, Munich, GRIN Verlag, https://www.grin.com/document/381247