Animal-related fatalities--part II: characteristic autopsy findings and variable causes of death associated with envenomation, poisoning, anaphylaxis, asphyxiation, and sepsis

In addition to blunt and sharp trauma, animal-related fatalities may result from envenomation, poisoning, anaphylaxis, asphyxiation, and sepsis. Although the majority of envenomation deaths are caused by hornets, bees, and wasps, the mechanism of death is most often anaphylaxis. Envenomation resulting from the injection of a poison or toxin into a victim occurs with snakes, spiders, and scorpions on land. Marine animal envenomation may result from stings and bites from jellyfish, octopus, stonefish, cone fish, stingrays, and sea snakes. At autopsy, the findings may be extremely subtle, and so a history of exposure is required. Poisoning may also occur from ingesting certain fish, with three main forms of neurotoxin poisoning involving ciguatera, tetrodotoxin ingestion, and paralytic shellfish poisoning. Asphyxiation may follow upper airway occlusion or neck/chest compression by animals, and sepsis may follow bites. Autopsy analysis of cases requires extensive toxinological, toxicological, and biochemical analyses of body fluids.     

Histologic evidence of repetitive blunt force abdominal trauma in four pediatric fatalities

In cases of acute fatal child abuse, certain injuries, including cutaneous blunt force trauma, skull fractures, subdural hematomas, intra-abdominal hemorrhage, and retinal hemorrhages are common and well described in the pediatric and forensic literature. These gross findings at autopsy, when taken into consideration with scene investigation and interviews with caregivers, may indicate both a clear manner and cause of death. In such cases, the discovery of additional pathologic changes attributable to older abusive injuries helps support a conclusion of death due to inflicted trauma. We discuss four cases of fatal child abuse in which acute blunt force abdominal trauma was the cause of death. In each of these cases, careful examination with proper sectioning and microscopy of select abdominal tissues revealed that the acute tissue trauma was superimposed on a background of older, healing injury. This older trauma was characterized by classic histologic elements of tissue repair, including fibroblast proliferation, early scar formation, increased vascularity, and hemosiderin-laden macrophages. Iron and trichrome stains were used to confirm the presence of hemosiderin and fibrosis in all four cases, but the recognition of fibroblast proliferation and a reactive vascular pattern was best seen on routine hematoxylin and eosin stains. The gross and microscopic autopsy findings, along with available investigative information, established the diagnosis of chronic physical abuse.     

Discrimination of falls and blows in blunt head trauma: systematic study of the hat brim line rule in relation to skull fractures

In the discrimination of falls from blows in blunt head trauma, the hat brim line rule is one of the most often used criteria. The present study assesses the validity of the hat brim line rule for skull fractures and looks at other possible criteria. All autopsy cases were retrospectively analyzed on a 5-year period. Cases selected consisted of downstairs falls (n = 13), falls from one's own height (n = 23), and homicidal blows (n = 44). Results show that fractures above the hat brim line are more in favor of blows, while fractures in the hat brim line zone are more difficult to distinguish. The majority of fractures were located on the left side for homicidal blows and on the right side for falls. A higher average number of lacerations was revealed for homicidal blows. In conclusion, this study establishes three criteria in favor of blows: (i) localization of a wound above the hat brim line; (ii) left side lateralization; and (iii) a high number of lacerations.     

Occlusion of left and right coronary arteries and coronary sinus following blunt chest trauma

Blunt chest trauma from rapid automobile airbag deployment causing coronary artery occlusion and myocardial infarction is a rare but potentially fatal condition. We present the case of a 37-year-old man who developed extensive anterior and inferior myocardial infarction because of occlusion of both left anterior and right coronary arteries following blunt injury to the chest in a car accident. The patient was scheduled for emergency coronary angiography but left and right coronary ostia were not cannulated because of thrombus formation probably. The patient died, and the autopsy revealed external compression by epicardial hematomas involving separately left and right coronary arteries and the coronary sinus without signs of coronary and/or aortic dissection. To our knowledge, this is the first case presenting occlusion of both coronary arteries secondary to blunt chest trauma causing acute myocardial infarction in a young man without signs of prior coronary artery disease.     

Advantage of affinity histochemistry combined with histology to investigate death causes: indications from sample cases

Mast cell histochemistry has been proposed in addition to classic histological methods to estimate the course of traumatic events before and after death. We have addressed the utility of this approach on nine victims of different types of trauma. Sections of wounded skin were stained with hematoxylin and eosin and with fluorescent avidin to tag mast cells. Mast cell numbers were evaluated by both direct and digitalized counts. Intact skin was used as control. The results on mast cells implemented the findings upon hematoxylin and eosin stain and helped to put the wounds and death in chronological sequence. Digitalized morphometry allowed to reduce intra- and inter-observer variation. We conclude that combined histological and histochemical analyses can be of practical use in forensic pathology, that a preliminary setting of the reference values is needed for each laboratory, and that image analysis can be of help for the quantification of the results.     

Amended cause and manner of death certification: a six-year review of the New Mexico experience

Little is known about the amendment of death certificates (DCs) issued by medical examiners and coroners. This retrospective study examined why, how, and with what frequency cause and manner of death were amended on DCs issued by forensic pathologists over a 6-year period at the New Mexico Office of the Medical Investigator. Approximately 1% of DCs had either cause or manner of death amendments, with arteriosclerotic cardiovascular disease and intoxicants the most commonly amended and resulting causes of death, respectively. There was a significant association between manner of death and number of DCs amended (p<0.001). By percent, natural and suicide DCs were the most frequently amended. The way in which manner of death changed was significantly associated with the amount of time elapsed between DCs (p=0.04). Toxicology was the most common reason for DC amendment.     

Estimating the timing of long bone fractures: correlation between the postmortem interval, bone moisture content, and blunt force trauma fracture characteristics*

There is very limited knowledge about how long perimortem fracture characteristics persist into the postmortem interval (PMI). Therefore, in this study, 60 porcine long bones were exposed to natural taphonomic conditions and fractured with a steel bone breaking apparatus every 28 days throughout a 141-day period. Differences between macroscopic blunt force trauma fracture characteristics (fracture angle, surface morphology, and outline) were examined to determine if they varied over time or in relationship to bone moisture content (ash weight) and overall assessment. There are significant relationships between (1) PMI and percent ash weight (%AW), fracture surface, and fracture angle and (2) %AW and fracture surface and fracture angle. Bone moisture content correlates significantly with fracture morphology and other characteristics commonly used by forensic anthropologists to determine the timing of traumatic injuries. However, fracture characteristics normally associated with perimortem trauma can persist long into the PMI.