The document discusses various causes of sudden natural death that may require an inquest or autopsy to determine the cause. It covers deaths related to the circulatory system like ischemic heart disease, cardiomyopathy, and aortic dissection. It also discusses sudden deaths related to the respiratory system from things like pulmonary embolism or hemorrhage. Finally, it briefly touches on sudden neurological causes such as cerebral hemorrhage and epilepsy. The goal of the document is to provide forensic pathologists an overview of common natural causes of sudden unexpected death.

1. Dr. Javeria Akhtar

2.  The most fundamental objectives of an inquest is to ascertain facts pertaining to
the death i.e who the dead person was, when did he die, where did he die and how
did he die?
 Answers to these Qs are obtained from inquiry, post mortem examination(p.m.e)
 In other circumstances i.e; sudden, unexpected + unnatural deaths the body may be
released without an autopsy if there is sufficient evidence + materials to satisfy the
Coroner/ Magistrate on the cause, manner + circumstances of death.

3.  All deaths due to unnatural causes + deaths believed to be due to natural causes
but where the medical cause of death is not certain / known are subjected to an
inquest.

4.  DEATHS OCCURRING UNDER THE FOLLOWING CIRCUMSTANCES ARE SUBJECTED TO AN
INQUEST:
1. All unnatural, suspected unnatural, violent deaths, e.g homicides
Deaths apparently from natural causes but where the exact medical COD (cuase of death)
is not known.
1. Any death caused by an accident arising out of the use of a vehicle
2. Any death arising out of industrial employment, by accident, industrial disease
/industrial poisoning
3. Any death due to poisoning (alcohol intoxication, coal gas, insecticides,
barbiturates,etc)
4. Any death where the circumstances would seem to indicate suicide
5. Any death of a newborn child whose body is found
6. Death of a child from suffocation (including overlaying) OR deaths of foster children

5. 7. Deaths following anesthesia, surgery/ any medical investigative procedure
8. Any death resulting from an accident in the home, hospital/ institution/ any
public place.
9. Any death apparently caused by neglect (e.g.malnutrition)
10. Deaths in custody such as in police custody, remand prison, prisons, rehabilitation
centers, detention camps etc
11. Deaths in mental institutions, asylums, etc.
12. Deaths associated with pregnancy, abortion, childbirth etc. (maternal death)
13. Any death as a result of a fire/ explosion
14. Death by drowning
15. Any death (occurring not in a house) where deceased’s residence is unknown.

6.  A natural death in which no obvious criminal or accidental cause is identified, it
nevertheless 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.

8.  Definition: Death within 24 hrs from onset of symptoms
 Some accepts : death within 1 hrs of onset of symptoms - An unexpected witnessed
death (natural causes wit/out pre existing disease than occurs within 6 hrs of onset
of symptoms
 Cor. Heart Disease > 75 % of sudden Cardiac Deaths other Cardiac conditions: 20 % of
cases. COD remains unknown : 1 – 2 % of cases

9.  Deaths resulting from diseases and disorders of the circulatory system account for the
vast majority of sudden natural deaths.
 They are considered under diseases of the vessels, the heart muscles and the heart
valves.
 In some cases there is an overlap from one system to another.
 Following are the diseases that can lead to sudden death
1. Ischemic heart disease (coronary vascular diasease)
2. Hypertensive heart disease
3. Aortic valvular disease
4. Cardiomyopathy
5. Myocarditis
6. Aortic dissection

10.  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.

12.  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.
 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.
 Death occurs quite suddenly and unexpectedly.
 There may be an incident of exertion, anger, emotion and stress but equally the
death may follow a period of rest.
 One reason for a sudden collapse and death is that the mass of heart muscle has
outstripped its own blood supply.

13.  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.

14.  Cardiomyopathy is a general term for diseases of the heart muscle, where the
walls of the heart chambers have become stretched, thickened or stiff. This
affects the heart's ability to pump blood around the body.
 Types:
1. Hypertrophic cardiomyopathy.
2. Dilated cardiomyopathy.
3. Arrhythmogenic cardiomyopathy.
4. Restrictive cardiomyopathy.

15.  The natural history demonstrates that cause of death can be due to
1. progressive congestive heart failure
2. complication of thromboembolism
 Post mortem changes can be
1. a heavy heart with dilated ventricles
2. no inflammatory myocardial or coronary artery disease.
3. heart shows asymmetric left ventricular hypertrophy
4. the septal bulging together with a
5. septal endocardial plaque
6. anterior mitral valve leaflet thickening

17.  Inflammatory disease of cardiac muscle caused by inflammatory infiltrate of
immunocompetent cells following any kind of cardiac injury
 Cause of death may be cardiac arrhythmia secondary to infiltration of the
conduction system of the heart by inflammation or due to myocyte damage caused
by the inflammatory infiltrate, leading to cardiac failure and cardiogenic shock.

18.  Aortic dissection is a serious condition in which there is a tear in the wall of aorta
 Tearing in the innermost lining of the arterial wall of aorta that allows blood to
enter between the intima and media , thus creating a false lumen.
 During an aortic dissection the inner layer of aorta tears, letting blood in where it
usually doesn’t go.
 This causes the inner and middle layers to separate, or dissect.
 If the blood bursts through the outer wall of aorta, it’s life-threatening and needs
immediate repair.
 Autopsy findings are:
1. Cystic degeneration of the media
2. Dilatation of the ascending aorta
3. Cardiac hypertrophy
4. Bicuspid aortic valve

20.  The main causes are
1. Massive haemorrhage in the air passages
2. Pneumothorax
3. Infections
4. Asthma.
5. Pulmonary embolism

21.  When a massive haemorrhage occurs into the major air passages 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. Example: Tuberculosis, produces a massive bleed and death
follows very shortly
 In former years the frequency of syphilitic aortic aneurysms in the thorax means
that many would erode into a bronchus leading to a rapid death
 Severe hypovolemic shock from uncontrolled bleeding and respiratory failure
due to airway obstruction caused by blood clots are the main causes of death.
 Bleeding is usually a result of ulcerations with subsequent necrosis of adjacent
vessels
 Rupture of the tortuous vessels and hypertrophy due to chronic inflammation in the
bronchial arterial system

22.  Lung cancer
 Pneumonia
 Lung abscess
 Bronchiectasis
 Acute bronchitis
 Tuberculosis
 Asthma
 Pulmonary embolism
 Pneumothorax

23.  Diffuse bilateral pulmonary or alveolar haemorrhage (PH) can be found.

24.  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.

25.  During conventional autopsy, the pneumothorax test is a special examination
process in which the examiner punctures the intercostal muscles under water and
observes whether there are bubbles formed.
 Therefore, it is not part of the routine examination in each autopsy, and forensic
pathologists may neglect the process and miss the findings.
 Total lung collapse and mediastinum shift to the intact side after exposure of the
chest cavities may be detected during conventional autopsy, but not every
pneumothorax has such significant lung collapse.
 PMCT (post mortem CT scan) has shown diagnostic value in tension pneumothorax
and played a supporting role in determining the cause of death.

26.  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).
 Autopsy findings: On autopsy, an embolus can be seen in the left main bronchus
however, multiple thrombi can also be seen.

28.  Whilst most chest and lung infections can produce a severe illness which may lead
on slowly to death, there are few bacterial and viral infections, which can produce
sudden and unexpected deaths in very short time causing hemorrhagic
bronchopneumonia.
 Chronic bronchitis can also on occasions cause a sudden death.

29.  Lung tissue or postmortem culture isolates pathogen responsible for infection
 Consolidative pneumonia
 Interstitial inflammation
 Diffuse alveolar damage

31.  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.

32.  Greyish white Mucus plugs that completely occlude the airway
 Diffuse alveolar damage
 Lungs are hyper inflated, over expanded appearing like a balloon occupying whole
thoracic cavity

34. Causes of sudden death pertaining to nervous system
 Nearly always caused by hemorrhage which may occur either within the brain, or
outside within the meninges. (subarachnoid hemorrhages, intracerebral
hemorrhages)
 Epilepsy
 Berry aneurysms
 Primary brain tumors
 Hydrocephalus

35.  This is often referred to as cerebrovascular accident
 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, so that the victim is
usually an elderly person with hypertensive heart disease and widespread
arteriosclerosis, especially of the cerebral arteries.
 May also occur in other sites such as pons or the cerebellum but they are much less
frequently seen.

36.  Bleeding between the innermost two membranes that cover the brain i.e: pia
matter and arachnoid matter
 This hemorrhage is usually traumatic (resulting from trauma to head) but can also
be non traumatic resulting from cigarette smoking and hypertension
 The major causes of death following subarachnoid haemorrhage are
1. effects of the initial bleed
2. aneurysmal rebleeding
3. delayed cerebral ischaemia.

38.  Cerebral edema
 Subarachnoid hemorrhage
 Intracranial vasculitis
 Arteriovenous malformation can also be present.
 Necrosis of blood vessel walls and their destruction

40.  The formation of a cerebral thrombus in one of the cerebral arteries at the base of
the brain, or in a smaller 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.
 A 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.

41.  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 epileptics ceases to breathe or aspirates regurgitated
vomit, or has an airway obstructed by the tongue.

42.  A saccular aneurysm is a rounded sac containing blood, that is attached to a main
artery or one of its branches. Also known as a berry aneurysm (because it
resembles a berry hanging from a vine)
 This is the most common form of cerebral aneurysm. It is typically found on arteries
at the base of the brain.

44.  Common types of brain tumors
1. Glioblastoma
2. Meningioma
3. Astrocytoma
4. Pituitary adenomas
5. Craniopharyngiomas

45.  Hydrocephalus is the buildup of fluid in the cavities (ventricles) deep within the
brain.
 The excess fluid increases the size of the ventricles and puts pressure on the brain.
 Cerebrospinal fluid normally flows through the ventricles and bathes the brain and
spinal column.

46.  A Massive bleed may occur when a gastric or duodenal ulcer erodes through the sub
mucosal tissues and into an artery lying close by.
 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.

47.  Fatty change to the liver can also produce a sudden death but the exact mechanism
remains unknown.
 In some cases there is microscopic evidence of fat embolization to the lungs or even
the heart or brain.
 Equally there may be a sudden disturbance to the nearby pancreas and insulin
activity.

48.  In pregnancy, sudden deaths are usually associated with haemorrhage.
 The rupture of an extra-uterine pregnancy may produce a massive intra-abdominal
haemorrhage 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.

49.  SUDDEN DEATH FROM UNKNOWN CAUSES: There is nothing more frustrating and no
case remains so memorable, than a death for which there is no demonstrable cause
 All pathologists of cases where, after autopsy, toxicology, bacteriology, virology,
histology and a review of the history of the case with all the professional concerned,
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.