Injury patterns in motor vehicle collision-youth pedestrian deaths.

OBJECTIVE: The objective of this study was to describe fatal pedestrian injury patterns in youth aged 15 to 24 years old and correlate them with motor vehicle collision (MVC) dynamics and pedestrian kinematics using data from medicolegal death investigations of MVCs occurring in the current Canadian motor vehicle (MV) fleet. METHODS: Based on a systematic literature review, MVC-pedestrian injuries were collated in an injury data collection form (IDCF). The IDCF was coded using the Abbreviated Injury Scale (AIS) 2015 revision. The AIS of the most frequent severe injury was noted for individual body regions. The Maximum AIS (MAIS) was used to define the most severe injury to the body overall and by body regions (MAISBR). This study focused on serious to maximal injuries (AIS 3-6) that had an increasing likelihood of causing death. The IDCF was used to extract collision and injury data from the Office of the Chief Coroner for Ontario (OCCO) database of postmortem examinations done at the Provincial Forensic Pathology Unit (PFPU) in Toronto, Canada, and other provincial facilities between 2013 and 2019. Injury data were correlated with data about the MVs and MV dynamics and pedestrian kinematics.The study was approved by the Western University Health Science Research Ethics Board (Project ID: 113440; Lawson Health Research Institute Approval No. R-19-066). RESULTS: There were 88 youth, including 54 (61.4%) males and 34 (38.6%) females. Youth pedestrians comprised 13.1% (88/670) of all autopsied pedestrians. Cars (n = 25/88, 28.4%) were the most frequent type of vehicle in single-vehicle impacts, but collectively vehicles with high hood edges (i.e., greater distance between the ground and hood edge) were in the majority. Forward projection (n = 34/88, 38.6%) was the most frequent type of pedestrian kinematics. Regardless of the type of vehicle, there was a tendency in most cases for the median MAISBR ≥ 3 to involve the head and thorax. A similar trend was seen in most of the pedestrian kinematics involving the various frontal impacts. Of the 88 cases, at least 63 (71.6%) were known to be engaged in risk-taking behaviors (e.g., activity on roadway). At least 12 deaths were nonaccidental (8 suicides and 4 homicides). Some activities may have been impairment related, because 26/63 (41.3%) pedestrians undertaking risk-taking behavior on the roadway were impaired. Toxicological analyses revealed that over half of the cases (47/88, 53.4%) tested positive for a drug that could have affected behavior. Ethanol was the most common. Thirty-one had positive blood results. CONCLUSION: A fatal dyad of head and thorax trauma was observed for pedestrians struck by cars. For those pedestrians hit by vehicles with high hood edges, which were involved in the majority of cases, a fatal triad of injuries to the head, thorax, and abdomen/retroperitoneum was observed. Most deaths occurred from frontal collisions and at speeds more than 35 km/h.

Injury patterns in motor vehicle collision-pediatric pedestrian deaths.

OBJECTIVE: To describe fatal pediatric pedestrian injury patterns and correlate them with motor vehicle collision (MVC) characteristics and pedestrian kinematics using data from medicolegal death investigations of MVCs occurring in the current Canadian MV fleet and determine the applicability of the classical "Waddell's triad" comprising knee, hip (femur) or pelvis and craniocerebral injuries to present data injury patterns. METHODS: An Injury Data Collection Form was used to extract MV, MVC, pedestrian demographic and injury information from the Office of the Chief Coroner for Ontario database using autopsy data from 2013 to 2018. Injuries were coded using the Abbreviated Injury Scale (AIS) 2015 revision. The study focused on AIS ≥3 injuries utilizing the Maximum Abbreviated Injury Scale (MAIS), MAIS by Body Region (MAISBR) and Injury Severity Score (ISS). RESULTS: Between 2013 and 2018, there were 25 pediatric deaths. The pedestrians were either struck and run over (n = 17, 68%; 56% low speed) or struck and projected (n = 8, 32%). Twenty-two deaths were from frontal impacts; three were from reversing vehicles. Fourteen of the 17 (82.4%) run over cases occurred at low speed (<30 km/h). In 9 (36%) cases, the vehicle was turning at impact (right n = 3, left n = 6). A majority of the vehicles had a high hood edge. The head was the most severely injured (median MAISBR = 5 overall and ≤10 years; median MAISBR = 6 for 11-14 years old) followed by the neck (MAISBR = 3 overall; 6-14 years old), and the thorax (median MAISBR = 3 overall; all age groups). For the early adolescents (11-14 years old), the serious injury pattern included the abdomen (median MAISBR = 3.5). Nearly half (n = 11, 44%) sustained brainstem injuries. Over fifty percent of the 16 cases with neck injuries (n = 9, 56.3%) had atlanto-occipital or axial dislocation. CONCLUSION: More than half of the deaths occurred during low speed run overs. MAIS ≥3 injuries trended to a dyad of head and thorax in ≤5 years old, a triad of head, neck, and thorax injuries in children 6-10 years old and a tetrad with the addition of abdominal injuries in pedestrians ≥11 years old. Waddell's triad was not applicable to the fatal cases in the present study.

Fatal methemoglobinemia: A case series highlighting a new trend in intentional sodium nitrite or sodium nitrate ingestion as a method of suicide.

Unintentional exposure to nitrite- or nitrate-containing toxic salts is a recognized cause of acquired methemoglobinemia (MetHb). This systemic alteration of the blood can be fatal if not recognized and treated promptly. The intentional ingestion of sodium nitrite (NaNO2) or sodium nitrate (NaNO3), causing MetHb, is an uncommon and recently identified method of suicide, with the first reported case in the literature occurring in New Zealand in 2010. In this case series we present 28 cases of sudden death of individuals with evidence of MetHb and/or toxic salt ingestion, occurring in the Province of Ontario, Canada, between the years 1980 and 2020, inclusive. Of the 28 deaths in our case series, 25 showed evidence of intentional ingestion of sodium nitrite or sodium nitrate salts. Our year-over-year data demonstrated this is an increasingly used method of suicide in our provincial population, with the majority of cases occurring in the final two years of our study. Postmortem detection of MetHb is typically established via screening techniques such as scene evidence suggesting fatal consumption of a toxic salt in addition to the characteristic grey-purple lividity observed upon the body. The diagnosis can be established via postmortem blood testing demonstrating elevated methemoglobin saturation. Additionally, we have confirmed that postmortem MRI in cases of MetHb demonstrates a T1-bright (hyperintense) signal of the blood; both within intracardiac blood on chest MRIs and postmortem blood samples in tubes.

Heart of glass: fatal hematemesis caused by bronchiole-cardiac fistula.

A 58-year old woman presented for autopsy after having been found unresponsive in a public bathroom surrounded by a pool of blood. During attempts at resuscitation, blood was noted in her airway. She had a past medical history that included surgical repair of Tetralogy of Fallot as a child. At autopsy, a shard of glass was identified projecting from the surface of the left lung, having formed densely fibrotic adhesions at the pleural surface. The glass also penetrated through a bronchiole lumen and into a previously surgically repaired bulging right ventricular outflow tract, forming a bronchiole-cardiac fistula, allowing for the massive hemoptysis that led to her death. After further inquiry, it was discovered that the decedent also had a history of seizure disorder and had fallen through a glass door during a seizure many years ago, requiring several shards of glass to be removed from her chest wall.

Traumatic subarachnoid hemorrhage and the COL3A1 gene: emergence of a potential causal link.

We describe two previously unreported associations in four cases. The first two cases demonstrate an association between segmental mediolytic arteriopathy and vascular Ehlers-Danlos syndrome. The second two cases illustrate an association between vascular Ehlers-Danlos syndrome and traumatic subarachnoid hemorrhage. In case 1, there was acute subarachnoid hemorrhage and mesenteric artery dissection. In case 2, there was an acute mesenteric artery dissection with intestinal infarction. In both cases 1 and 2, segmental mediolytic arteriopathy was found in the vertebral arteries. Cases 3 and 4 were sudden deaths from traumatic subarachnoid hemorrhage with intracranial vertebral artery rupture. Genetic testing in all four cases revealed point mutations in the type 3 procollagen gene (COL3A1), as observed in vascular Ehlers-Danlos syndrome. Based on the first two cases, we propose that segmental mediolytic arteriopathy may be a marker for this disease. We further suggest that vascular Ehlers-Danlos syndrome may be related to the pathogenesis of traumatic vertebral artery injury, in some cases. We recommend that cases of segmental mediolytic arteriopathy and traumatic subarachnoid hemorrhage undergo genetic testing for COL3A1 mutations.