Topic: Sudden, Unexpected, Natural Death in Adults
Subtopics:
Introduction
Death from cardiac causes
Death from non-cardiac causes
The reviews of the extensive literature on sudden death agree that there is a great inconsistency in definitions of sudden death. The question is “how sudden is sudden?”. The WHO definition of a sudden death is that it is someone who dies within 24 hours of appearance of symptoms. However, in forensic sense, most of deaths are in minutes or even in seconds of appearance of symptoms. A sudden death is not necessarily unexpected death and an unexpected death is not necessarily sudden, but very often the two are in combination. The vast majority of sudden death are due to natural causes. Most cases of sudden unexpected natural death result from a variety of chronic conditions that may seem to offer no immediate threat to the individual. Most sudden, unexpected deaths occur between the ages of one month and thirty years and after seventy years. The most common causes of death are clinically silent degenerative diseases.
Causes: Sudden, unexpected natural deaths can be divided into two essential categories: a) Deaths from cardiac causes b) Deaths of non-cardiac etiology.
a) Death from cardiac causes: Death from cardiac causes occur in two situations
a) There is a significant anatomic alteration in the heart such that the functional abnormalities are obvious.
b) There is no anatomical abnormalities found during autopsy.
When death is due to later situation then it is called functional death i.e. no anatomical abnormalities in found in the heart.
Where a natural death is very rapid, perhaps virtually instantaneous, the cause is invariably cardiovascular. Cardiovascular system accounts for the vast majority of sudden deaths. Cardiovascular disease is by far the most common cause of death in the Western world of which more than 80% are due to coronary atherosclerosis. Hypertension accounts for a much smaller number of deaths but may be under-reported since many pathologists are not willing to designate hypertensive cardiovascular disease as a cause of death in the absence of supporting clinical data.
a) Causes of functional death
Spontaneous Ventricular Fibrillation: A meanwhile healthy man can die from ventricular fibrillation as he may collapses suddenly or during exertion. In those patients evidence indicates that these individuals have electrically unstable hearts and that they suffer a fatal dysrhythmia related to adrenergic discharge. The manner of death may be natural, accidental, or homicidal.
Vagal cardiac inhibition: This may be the cause of death within seconds to minutes followed by trauma. The death is classified as accidental as no obvious wound is produced. Examples of such trauma are blow to larynx, kick to scrotum, blow to upper abdomen, etc. The death in these scenario can be due to homicide as well.
Electrocardiographic Syndromes: Certain syndromes or functional abnormalities that are only depicted by echocardiography may be the cause of sudden cardiac death in adults. Examples are Wolf Parkinson White Syndrome (WPW) syndrome, long QT syndrome, sinus sick syndrome ,etc.
b) Cause of death to structural abnormalities in the heart:
Atherosclerosis of coronary arteries: The sign or symptom in patient with coronary artery disease may be sudden death that may occur during exertion, taking bath, sexual intercourse , sleeping or any other time. The cause of death in such patient is myocardial ischemia or infarction as atheromatous plaque occlude blood to heart itself. The plaques occludes the coronary arteries supplying the heart muscles . Sudden death is triggered by certain environmental factors. Exercise increases heart rate and causes greater oxygen demand by the myocardium. Exercise also increases catecholamine levels that sensitize the myocardium to dysrhythmias. Severe changes of heat and cold in the climate may also stress the heart and predispose to anginal attacks and sudden death due to myocardial infarction. Most individuals who die suddenly and unexpectedly from coronary occlusion have at least two vessels involved. Atheroslerotic occlusion of at least 75 percent of the coronary arteries is required for infarction to occur. Most commonly involved coronary artery is left anterior descending artery followed by right coronary artery. Coronary atherosclerosis is a very common finding at autopsy, and it develops over a period of years and is compatible with a vigorous life. One must take into account all of the findings and circumstances of the case before a final conclusion is justified. Even when a recent myocardial infarct is present, the victim may have died from some other cause entirely.
Time determination of death by analyzing the histology of infarct tissue of the heart:
<5 hours: PAS stained myocytes
5-24 hours: Appearance of neutrophils to appearance of degenerating neutrophils
1-3 days: Exclusively neutrophils and their degenerating forms
4-6 days: Neutrophils, eosinophils, macrophages, pigment, fibroblasts, capillaries
7-14 days: Neutrophils, eosinophils, macrophages, pigment, fibroblasts, capillaries, lymphocytes, plasma cells
2-8 weeks: As previous, but no neutrophils
>2 months: Connective tissue condensed; minute foci of necrosis may still persist. Exudate has essentially disappeared, but a small number of lymphocytes and pigmented macrophages may be seen until one year.
Non-atherosclerotic Coronary Artery Disease: Congenital anomalies of the distribution of the coronary arteries can be the etiology of sudden death in adults and children. The anomalies vary:
ü Origin of the left coronary artery from the right sinus of Valsalva with the artery passing between the aorta and pulmonary artery
ü Only a single coronary ostium in the right sinus of Valsalva with the left coronary artery arising from the proximal right coronary artery
ü Origin of the right coronary artery from the left sinus of Valsalva
ü Origin of the left coronary artery from the right sinus of Valsalva with the artery passing dorsal to the aorta rather than between the aorta and pulmonary artery
ü Coronary artery hypoplasia, although no diagnostic criteria have been set forth for this entity.
Sudden death appears to be more likely when the anomalous artery forms an acute angle with the sinus of Valsalva or a right angle in the artery.
Sudden death can also be associated with a condition called "bridging". In this abnormality the left anterior descending, dips down into the myocardium to pursue an intramyocardial course instead of following its usual course in the epicardial fat. Sudden death as a result of this anomaly is also a diagnosis of exclusion and depends upon the totality of autopsy findings and circumstances of death.
Left Ventricular Hypertrophy and Hypertensive cause: Left ventricular hypertrophy is associated with electrical instability like ventricular ectopy and ventricular tachydysrhythmias and thereby, sudden death. The association exists whether coronary atherosclerosis is present or not. Hypertension is the most common etiology of concentric left ventricular hypertrophy, also known as pressure hypertrophy, which involves the septum and free wall symmetrically with no enlargement of the chamber. It may develop in a matter of weeks in hypertension. It may also be associated with aortic valvular disease, thyrotoxicosis, and aortic coarctation. In hypertension the right ventricle is usually also hypertrophied, and the pulmonary pressures are increased. Sometime the only autopsy finding after sudden death is left ventricular hypertrophy. But in hypertensive patients atherosclerosis can be seen.
Myocarditis: It may occur as the result of systemic infection, or it mav follow respiratory infection or be of unknown or uncertain origin. It may be acute, subacute, or chronic. It can be caused variety of known etiologic agents, including bacteria, viruses,rickettsia, fungi, protozoa, or helminths. It may also be a manifestation of autoimmune disease. The patient can suddenly die from arrhythmias caused by myocardium necrosis. Dysarrthymias like premature ventricular contractions and ventricular tachycardia are the cause of sudden death .
Cardiac Valvular Disease : Rheumatic fever is the major cause of valvular disease like mitral and aortic stenosis in the developing countries like Nepal . So those findings are quite commonly found in autopsies on cases of sudden death in Nepal. Calcific aortic stenosis may result from congenital malformations of the valve usually a bicuspid valve , rheumatic inflammation in which the cusps become fused, secondary calcification of the bicuspid valve leaflets. plications. The most common valvular disorders currently associated with sudden death are mitral valve prolapse syndrome (also referred to as myxomatous degeneration of the mitral valve, floppy mitral valve, Barlow's syndrome) and aortic stenosis. In intravenous drug abusers sudden death can occur from an acute valvulitis, usually of the tricuspid valve.
Other causes of sudden unexpected death from cardiac causes are as follows:
Congenital heart diseases
Valvular heart diseases (rheumatic, syphilitic, etc.)
Hypertensive diseases
Infections (myocarditis, post infectious myocardial degeneration)
Cardiac tamponade : After ruptured myocardial infarct, trauma, there is collection of blood in pericardial sac. About 250 to 300 ml blood may act fatal, making heart unable to function normally, resulting in cardiac standstill leading to death.
Obscure conditions such as cardiomyopathies, Fiedler’s myocarditis, etc.
Aortic aneurysms of atherosclerotic or dissecting type
Death from non-cardiac causes:
Respiratory System : Most of the causes of sudden death within the respiratory organs are again vascular. Pulmonary embolism is a common and in fact is the most under-diagnosed cause of death. In almost every case, the source of emboli is in the leg veins, as pelvic thrombosis is very rare. After any tissue trauma, especially where immobility or bed rest occurs, deep vein thrombosis develops. Some produce no lung lesions at all, others produce infarcts, which may or may not lead to clinical signs, and a minority block major vessel and cause death. Majority of cases of pulmonary embolism deaths have predisposing cause such as fractures, tissue trauma, surgical operation, burns trauma, bed rest, forced immobility, etc. but others occur unexpectedly in normal people. Various causes of sudden natural death of respiratory system origin are:
Pulmonary embolisms Massive hemoptysis (from pulmonary tuberculosis) Severe infections such as fulminating viral pneumonia (usually influenza) Chronic asthma/status asthmatics Anaphylaxis Obstruction of respiratory tract
Intracranial Vascular Lesions: Commonly encountered intravascular lesions resulting in sudden natural death are:
Intracranial bleeding due to cerebral atheroma and stroke or hypertension
Subarachnoid hemorrhage from ruptured aneurysm
Cerebral thrombosis
Embolisms
Meningitis
Brain tumors, which can result in death due to increased intracranial pressure, sudden hemorrhage from tumor mass, etc.
Idiopathic epilepsy
Functional inhibition of the vagus nerve.
Gastrointestinal System :The major cause of sudden death within the gastrointestinal system are also mostly of vascular origin and they are:
Severe gastrointestinal bleeding due to gastric or duodenal ulcers
Ulcerative colitis, malignancies, etc.
Mesenteric thrombosis and embolism leading to infarction of the gut are not sudden, but may be rapid and remain undiagnosed
Perforation of peptic ulcer can be fatal in hours if not treated
Intestinal gangrene due to strangulated hernias and torsion due to peritoneal adhesions can be a fulminant and fatal condition
Aortic aneurysmal rupture
Diseased viscera undergoing rupture
Fulminant hepatic failure
Acute haemorrhagic pancreatitis.
Gynaecological Conditions : If a women in her child bearing age is found to be dead unexpectedly and suddenly, following should be considered as cause of death:
Complication of pregnancy must be first thought of, just to make a primary exclusion. Haemorrhage in female genital organs could be due to abortion or ruptured ectopic pregnancy, etc. and is an emergency that can result in death from intraperitonial bleeding, unless rapidly treated by surgical intervention.
Endocrinal Causes:Sudden natural deaths occur due to any one of the following: Adrenal insufficiency Diabetic coma Myxoedemic crisis Parathyroid crisis
Iatrogenic Causes: Following may be suspected and may have to be ruled out: Abuse of drugs Sudden withdrawal of steroids Anesthesia Mismatched blood transfusion
We do not own any of the contents in this blog. We are not hosting any copyrighted content, all the links provided in this blog are just randoms links already available somewhere in the internet. All the contents in this blog are only for educational purposes. If you think your right is infringed in any way, please let us know at js2269335@gmail.com. We will remove the link as soon as possible.
No comments:
Post a Comment