Case 5 -

Acute Myocardial Infraction of 3-5 Days Duration on a Background of Older Myocardial Infraction Christopher Milroy, The Ottawa Hospital, Ottawa, ON

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Clinical History 53 year old male. Had a confrontation with the police. He was taken to a police station where he was declared fit for interview by a medical officer and released after a few hours detention. He subsequently complained of back pain, collapsed and could not be resuscitated. Can you date the lesions(s) seen on microscopy ? Pertinent Laboratory Data: Toxicology was negative Vitreous biochemistry was unremarkable Case 5 - Figure 1 Case 5 - Figure 2 Case 5 - Figure 3 Case 5 - Figure 4 Case 5 - Figure 5 Case 5 - Figure 6 Case 5 - Figure 7 Case 5 - Figure 8 Case 5 - Figure 9 Introduction: This case involved a 53 year old man who was involved in a incident with the police. He was sprayed in the face with CS spray, a noxious and acutely stressing agent. Four days later he collapsed and died unexpectedly. He was a diabetic. There was a history of chest pain before the event, that was provided before the autopsy but this was subsequently disputed by his family. At autopsy there was a macroscopic infarct and coronary artery thrombosis Pathological/Microscopic Findings and any Immunohistochemical or Other Studies: There is an acute myocardial infarct on a background of older myocardial infraction. The dating of the acute infarct suggests it is 3-5 days old. This time span straddles the event. Differential Diagnoses: The differential diagnosis in this case relates to whether the acute infarct dates from around the time of the infarct or was older. This timing is central to the issue of whether the use of CS spray precipitated the acute infarct, as the use of the CS spray was contoversial. If a noxious agent precipitates an acute myocardial infarct and that act was illegal, then the possibility of homicide by natural causes is raised. Final Diagnosis: Acute Myocardial Infraction of 3-5 Days Duration on a Background of Older Myocardial Infraction. Case Discussion: Acute myocardial infarction (AMI) is a very common entity and can raise a number of Forensic Pathology questions. The presence of acute myocardial infarction does not necessarily mean the manner of death is natural. Use of stimulant drugs of abuse may precipitate AMI and their presence would mean the manner of death would be an accident. Where an unlawful act causes an AMI then the possibility of homicide by natural causes is raised. More common than AMI at autopsy in sudden death is macroscopic stable coronary artery disease. In these cases the presence of other changes may help determine whether the death is cardiac or not. Changes such as acute plaque hemorrhage and early microscopic changes may help, but are often absent. Timing of myocardial infarction is, in reality not that common a forensic issue but may be important in accidents and homicides. The changes allow a likely time range, but it is not possible to be specific about timing based on pathology alone, but rather a range should be given. However a basic timing schedule on hematoxylin and eosin staining is: 0-12 hours - No significant changes 12-24 hr myocyte eosinophilia, 24 hr - neutrophil infiltrate at periphery 36 hr - Neutrophil karyorrhexis starts 3-5 dyas - Myocytes lack nuclei and banding. Prominent karyorrhexis 4-5 days - Macrophages with hemosiderin start 7 days - Granulation tissue starts to form Most cases of sudden death with ischemic heart disease occur before histological changes are evident. Review of the Literature/Treatment Options: Precipitating events of acute myocardial are important for the forensic pathologist as they may be central to legal proceedings. Often there is stable coronary artery disease present at autopsy. Less often there is obvious acute myocardial infarction. Establishing the precipitating event requires an analysis of history, cardiac findings and toxicological analysis. The epidemiological studies on earthquakes, the Iragi missile attacks on Israel and watching sporting events have shown that emotional stress as well as physical exertion can precipitate acute myocardial infraction. Studies on stimulant drugs have also shown these can precipitae acute myocardial infraction. Conclusion(s): Ischemic heart disease and acute myocardial infarction remain major causes of sudden death. The manner of death in the presence of stable ischemic heart disaese or acute myocardioal infarction cannot simply be dismissed as natural, as use of drugs or physical or emotional stressors may change the manner of death References: Meisel SR, Kutz I, Dayan KI et al. Effect of Iraqi missile war on incidence of acute myocardial infarction and sudden death in Israeli civilians. Lancet 1991; 338;660-661 Mittleman MA, Maclure M, Tofler GH etal al. Triggereing of acute myocardial infarction by heavy physical exertion. NEJM 1993;329:1677-83. Brown DL. Disparate effects of the 1989 Loma Prieta and 1994 Northridge earthquakes on hospital admissions for acute myocardial infarction.: Importance of superimposition triggers. Am Heart J 1999;137:830-6) Carroll D, Ebrahim S, Tilling K et al. Admissions for myocardial infarction and world Cup football:database survey. BMJ 2002;325: 1439-42. Karch S. Karch's Pathology of Drug Abuse 4th Ed. CRC Press Bota Raton 2009 Burke A, Tavora F. Practical Cardiovascular Pathology Wolters Kluwer LWW.Philadelphia 2011