jiafm, 2010-32(2) april-june. - forensic medicine

ISSN 0971-0973 J Indian Acad Forensic Med, 32(2)were noted in that region. Heart weighs 258 gms andthe LAD coronary lumen shows about 95% block.The reason for not finding any injuries over thorax,external or internal, was attributed to the fact that thisregion was covered with thick layering of clothes.There was no significant past or familymedical history in these two cases. The cause ofdeath in both cases was acute myocardial infarctionas a result of coronary artery disease consequent toblunt trauma thorax.Discussion:Acute myocardial infarction secondary to ablunt thoracic trauma is rarely described as acomplication in cardiac injuries related to trauma. [5]This issue is rarely approached in systematic studiesand it is more frequently found as case reports inliterature revised; therefore, its prevalence and theincidence of associated abnormalities in ancillaryexaminations may be underestimated. Maenza andcolleagues performed a meta-analysis on cardiaccomplications in blunt cardiac trauma including morethan 4600 patients. The prevalence of cardiaccomplications varied between 2.6% and 4.5%.Myocardial infarction or complications assuminginfarction occurred only in a minority of the patients(between 5 and 7%). [6] Christensen et al. identified77 published cases of acute myocardial infarction inblunt chest trauma. [7]Although coronary artery atherosclerosis isthe most common cause of AMI, 20% of acutemyocardial infarctions in young adults have a nonatheroscleroticetiology such as coronary arteryembolism, hypercoagulation status, congenitalcoronary abnormalities, dissection of coronaryarteries, coronary artery spasms (including the use ofcocaine), vasculitis and mediastinal irradiation. [8, 9]BTT is another possible underlying mechanism ofacute myocardial infarction in young patients.Clinically significant cardiac injury occurs inapproximately 5 to 20% of patients with nonpenetrating thoracic trauma, and up to 76% in severecases of BTT. [10] The time interval from injury tocoronary vessel occlusion showed a highly variablecourse reaching from immediate onset to a delay ofseveral weeks. [11]Potential mechanisms of non-penetratingcardiac injury include fast acceleration ordeceleration, direct chest trauma, heart compressionbetween the sternum and thoracic segment of thespine, and fast increase of intra-aortic pressure due toabdominal or lower limb compression. Themechanisms that contribute to myocardial infarctionmay include intimal injury, subintima hemorrhage,intraluminal thrombosis and spasm.Any coronary artery may become involved,although the anterior descending artery is the mostcommonly cited artery in case reports followed bythe right coronary and circumflex arteries. [12, 13]Coronary artery injury is more frequently diagnosedin patients less than 45 years of age victims of roadaccidents. [14] Minor traumas have rarely beenreported as the cause of coronary artery injury. [15]Early diagnosis is usually difficult becauseof low frequency, non-specific clinical picture andthe level of suspicion by the assistant physician.Chest or abdominal pain following the trauma can bein most instances attributed to a contusion of bonesand soft tissues, which can mask the pain of cardiacorigin.Appropriate diagnostic tests must beconsidered in patients who suffer a BTT.Electrocardiogram must be performed in allsuspected cases. Measurement of cardiac enzymes,chest X-ray and echocardiogram can help in thediagnosis of cardiac trauma.The treatment of acute myocardial infarction causedby blunt chest trauma may be complicated by theseverity of accompanying injuries, and most of thecases have been managed conservatively. [16, 17]Successful thrombolytic treatments of coronaryocclusions in patients with blunt chest trauma havebeen reported. [18, 19] However, many traumapatients will not be candidates for thrombolytictherapy because of the risk of hemorrhage fromcoexisting injuries. [20]The conclusion drawn from these two casereports is that the clinical examination with high levelof suspicion and an electrocardiogram in all cases ofpossible cardiac trauma must be part of the initialmedical care of patients who have suffered a BTT.Acute myocardial infarction must early be consideredin the differential diagnosis of patients who arevictims of BTT, regardless of the intensity of trauma.References:1. Mattox KL, Feliciano DV, Burch J, Beall Jr AC,Jordan Jr GL, De Bakey ME. Five thousand sevenhundred sixty cardiovascular injuries in 4459 patients.Epidemiologic evolution 1958 to 1987. Ann Surg.1989; 209: 698-705.2. Vanezis P. Post-traumatic thrombosis of the rightcoronary artery. Med Sci Law. 1986; 26: 107-12.3. Barton EN, Henry R, Martin AS, Ince W,Bartholomew C. Acute myocardial infarctionfollowing blunt chest trauma due to the kick of cow.West Indian Med J. 1988; 37: 236-9.4. Mattox KL, Estrera AL, Wall MJ. Traumatic heartdisease. In: Zipes DP, Libby P, Bonow RO, BraunwaldE (eds). Braunwald‟s heart disease: a textbook ofcardiovascular medicine. 7th ed. Philadelphia: ElsevierSaunders; 2005. p. 1781-8.5. Vlay SC, Bluementhal DS, Shoback D, Fehir K,Bulkley BH. Delayed acute myocardial infarction afterblunt chest trauma in a young woman. Am Heart J.1980; 100: 907-16.6. Maenza RL, Seaberg D, D'Amico F. A meta-analysisof blunt cardiac trauma: ending myocardial confusion.Am J Emerg Med 1996, 14: 237-41.166