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Definition

Unexpectedly death within 24

hrs from onset of symptoms with or

without known preexisting conditions.

In forensic view most of cases occur within

minutes or even seconds from

onset of symptoms.

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SUDDEN DEATH

There are no obvious criminal or accidental causes, and becomes of

some concern to the forensic pathologist simply because of the difficulty or even impossibility to

furnish a certifiable cause of death.

The numerous causes of sudden natural death may conveniently be classified according to the different anatomical

systems of the body.

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Causes of sudden death

Cardiovascular System

Respiratory System

Gastrointestinal System

Gynecological conditions

Central Nervous System

Other

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Heart

• The heart of an adult Indian – Male 275-300 g – Female 225-250g

• Thickness – Atrial wall 1-2 mm – Right ventricle 3-5 mm – Left ventricle 10-15 mm

• Layers of the heart – Outer epicardium – Middle myocardium – Inner endocardium

• Heart enclosed by visceral and parietal pericardium

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Blood supply

• The Left Coronary Artery: originating from the left aortic sinus, after a short course, bifurcates into:

– Left anterior descending which runs in the anterior inter-ventricular groove, provides blood to anterior left ventricle, the adjacent anterior right ventricle and anterior two thirds of the inter-ventricular septum

– Left circumflex branch, which runs in left atrio-ventricular groove, supplies the lateral wall of the left ventricle

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Blood supply

• The Right Coronary Artery runs in the right atrio-ventricular groove. It usually nourishes the remainder of the right ventricle and the postero-septal region of the left ventricle, including the posterior third of the inter-ventricular septum.

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The localization of atheroma or thrombus

• Left anterior descending (left anterior inter-venrticular) (45-64%)

• Right main coronary (45-46%)

• Left circumflex coronary (3-10%)

• Left main coronary (0-10%)

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Type of occlusion

• Simple atheroma

• Ulcerative atheroma

• Sub-intimal hemorrhage

• Coronary thrombosis

• Per arteritis Nodosa

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Ischemic Heart Disease

Interruption or interference with the blood flow to the heart along the coronary arteries will have

profound effects on the heart itself

In the extreme-the heart will suddenly cease

functioning

In less extreme, areas of the heart will fail which in

turn causes a chain reaction and finally the complete heart failure.

At autopsy, one or more of the main branches of the

two coronary arteries may show of severe disease

process.

There will be a deposition of soft white or yellow

necrotic fatty material on the lining of the arteries.

Ischemic Heart Disease

Myocardial infarction occurs when there is 70% blockage or more in the lumen of one or more of the main coronary arteries.

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Cardiac temponade

• Cardiac tamponade is caused by a large or uncontrolled pericardial effusion due to trauma or after subacute setting after myocardial infarction (heart attack) which result in pressure on the heart muscle.

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Hypertensive Heart Disease

An enlargement of the left ventricle of the heart with accompanying increase in the

thickness of the muscle wall will result in a raise blood pressure, frequently to a level

twice as high as normal.

So that, rupture of vessels is frequently seen in the presence of hypertension –

raised blood pressure, example: rupture of a cerebral artery.

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The cardiac enlargement almost limited to the left ventricle, the three remaining usually within normal size.

In many cases the cause for cardiac enlargement is unknown, when the term primary or essential hypertension is used.

Hypertensive Heart Disease

• HTN may kill person in a number of ways :

– Cerebral stroke

– Renal failure

– Rupture aneurysm

– Primary HF called “cardiac asthma” or “paroxysmal nocturnal dyspnea” produced by the massive pulmonary oedema due to HTN

• Weght of heart >400g

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Aortic Valve disease

Sudden death result because of the hypertrophied left ventricle to force the

blood through the diseased and narrowed valve.

An alternative reason is that the disease process may spread out from the valve and impede the entry of blood into the ostia of the nearby coronary arteries.

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Hypertrophic obstructive cardiomyopathy (HOCM)

• Hypertrophic obstructive cardiomyopathy (HOCM) is a disease that results in abnormal thickening of the myocardium most commonly in the interventricular septum

• HOCM can result in clinical heart failure, life-threatening arrhythmias, mitral regurgitation and sudden cardiac

death.

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Sequence of Coronary occlusion

Sudden Death

Myocardial Infarction

Arrhythmia

Left ventricular failure and cardiogenic shock

Rupture of the Myocardium

aneurysms

Myocardial Fibrosis

Mural Thrombosis and Embolism

Pericarditis

Post-myocardial Infarction Syndrome (Dressier Syndrome)

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RESPIRATORY SYSTEM

• The main causes are:

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Pulmonary Embolism

massive haemorrhage

in the air passages

pneumothorax

asthma

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Pulmonary Embolism

Pulmonary embolism (PE) is a blockage of the main artery of the lung or one of its branches by a substance that has travelled from elsewhere in the body through the bloodstream (embolism) especially from deep vein thrombosis (DVT).

Usually results after prolonged immobilization, pregnancy, obesity, catheterization (endothelial injury).

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Haemorrhage in the Air Passages

When a massive haemorrhage occurs into the major air passages due to

trauma, death results from an obstruction to normal respiratory

gaseous exchange.

Erosion of a large pulmonary vessel by a malignant tumor or by an expanding

pulmonary infection (TB).

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Pneumothorax

The spontaneous rupture of an emphysematous bulla on the periphery of a lung. e.g.: following a bout of coughing or straining during some physical exertion, can be lead to a massive escape of air into one of the pleural cavities.

The vacuum normally present is lost and there is an immediate collapse of the affected lung.

In the absence of special medical equipment death may rapidly ensue, especially if there is concomitant disease in the other lung in the heart.

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Asthma

Asthma is the sudden and

prolonged spasm of the smooth muscles in the

walls of bronchioles.

The bronchospasm causes sever

constriction of the air passages.

In the case, the death is due to

respiratory failure in the exchange of oxygen and carbon dioxide within the

lungs.

This may due to obstruction in the

airways, restriction in the ability to

expand the lungs, allergic

neuromuscular problems and

ventilation abnormalities.

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GASTROINTESTINAL SYSTEM

A Massive bleed may occur when a gastric or duodenal ulcer erodes

through the sub mucosal tissues.

The profuse bleeding may pass down the

intestinal tract emerging from the anus, or it may enter the stomach and be vomited up, or more frequently it will pass in

both directions.

Another form of dramatic fatal bleeding occurs when varicose

and distended veins at the lower end of the esophagus become

eroded and burst. This usually occurs in a patient who had

developed severe fatty change or even cirrhosis

of the liver brought about by chronic alcohol

use.

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Gynecological conditions

In pregnancy, sudden deaths are usually associated with haemorrhage.

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The rupture of an extra-uterine pregnancy may produce a massive intra-abdominal hemorrhage

which on occasions has caused death.

Premature separation of a placenta previa may both cause severe exsanguinations unless there is medical

aid.

Attempts at abortion by inexpert persons may cause death either by perforation by the instrument of a major vessel, or by causing pulmonary embolus by

means of air, chemical fluids or the release of amniotic fluid into the blood stream.

CENTRAL NERVOUS SYSTEM

• Nearly always caused by hemorrhage

which may occur either within:

– the brain

– the meninges

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Cerebral Haemorrhage

This is often referred to as cerebrovascular accident,

although the word accident is a misnomer.

The massive bleed usually occurs

either within the basal ganglia or

more distally in the internal capsule.

The hemorrhage is

associated with raised blood

pressure

May also occur in other sites

such as pons or the cerebellum

but they are much less

frequently seen.

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Circulatory, non-hemorrhagic causes

The formation of a cerebral thrombus in one of the cerebral arteries at the base of the brain, or within the brain may cause loss of consciousness leading to death within a short time. The thrombus is usually formed in association with a localized plaque of arteriosclerosis.

The most unusual cause is that of a cerebral embolus, which may arise from an area of thrombus formation within the cavity of the heart, passing upwards to the brain via one of the carotid arteries.

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Epilepsy

Epileptic sufferers may die during a prolonged single seizure or more usually during a series of repeated seizures termed status epilepticus

Death is due to asphyxia if the epileptic ceases to breathe or aspirates regurgitated vomit, or has an airway obstructed by the tongue.

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SUDDEN DEATH FROM UNKNOWN CAUSES

There is nothing more frustrating than a death for which there is no

demonstrable cause

All cases where after autopsy, toxicology, bacteriology, virology,

histopathology and a review of the history of the case with all the

professional concerned, and there is no reasonable cause to be found.

One very special group of deaths which still remains a mystery is the sudden death in infancy syndrome.

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sudden death in infancy syndrome

• Incidence rate 1.5-3 per 1000 most common in first 12 months

• Risk factors – Higher rate incidence in winter – Death occur in region of Res. Disease – Male predominance – More in cities than rural areas – Mainly between 4-6 months – Increase incidence in twins, LBW, young mothers – Poor living conditions – Bottle-fed babies – Occur during night

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Pathophysiology

• Prolonged sleep apnea

• Cow’s milk coke more than human milk

• Airway obstruction

• Respiratory viruses

• Infants suffering from some occult illness

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