Its cause, mode, mechanism

& manner

What is death ? It is the brain stem death promoting the

removal of vital organs and essentiallyconsists of :

Deep unconsciousness ( no response

to external stimuli / internal need )

No movements / spontaneous breathing

Cessation of spontaneous cardiac rhythm

No reflexes

Bilateral dilation and fixation of pupils

Flat isoelectric EEG

PROVIDED THAT...

The following features are present

For a 24 hour period

Patients body temperature is not below 32o Celsius

Other metabolic & endocrine causes for coma have been excluded

……. by two doctors

The study of death is called thanatology

Its important to differentiate death from :

A ) stupor

patient appears asleep, responds only to vigorousstimulation & then lapsing back to somnolence.

B ) vegetative state

patient is unaware of self & environment but hasstable circulation, respiration & cycles of eyeopening & closing. Its due to bilateral cerebraldamage with intact brainstem.

Confusing terminology

Examples... A person dies of coronary. A thrombosis

Coronary thrombosis

Significant MI resulting

in LVFsyncope death

Example 2 A person was stabbed & left to bleed to death

bleeding from injury

Brain stem hypovolemia

CNS ischemia &

comadeath

Modes of death

ComaIt’s the state of insensibility of the central portion of the brainstem and thus can lead to death

Coma…..

Injuries or disease of the brain , if responsible

Congestion of the lungs, brain, & the meninges

Syncope (fainting)

It’s the sudden stoppage of the action of heart, that can be fatal & lead to death

Causes of syncope Sudden & excessive hemorrhage

Carotid sinus syndrome

Myocardial weakness : fatty degeneration , pompes disease , MI & post MI fibrosis , cardiomyopathies , myocarditis , exhausting diseases

Massive blood loss & hypovolemia

Reflex sympathetic

vaso constriction

Cerebral ischemia, syncope &

death

At the autopsy... Heart Shrunken & the chambers empty in case of

hypovolemia

Chambers dilated & filled with blood in case of asthenia

Lungs, abdominal organs, brain: pale

Asphyxia It is the mode of death caused by interference in normal

respiration

Nervous tissues are affected first as they are the least susceptible to hypoxia

interference

Hypoxia

or / and

hypercapnoea

Unconsciousness

and

death

Types of anoxia (Gordon's classification)

Anoxic

O2 is unable to reach the circulating blood

• Airway blockade

• Lack of o2 in air

Anaemic

Reduced o2 carrying capacity of blood

• Anaemia

• Massive bleeding

• NO3, CO poisoning

Stagnant

Impaired circulation reducing o2 delivery to tissues

heart

failure

Thrombus

Histotoxic

Block of oxidative phosphorylation (inhibition of cytochrome oxidase)

• Cyanide poisoning

Types of asphyxia

1)Mechanical obstructionClosure of ext.

respiratory orifices

(smothering)

Closure of airway by ext.

pressure on neck

(Hanging, strangulation)

Closure of airway by impacted

foreign bodies

(choking)

External compression of

chest/ abdominal wall disabling

respiration

Airways & alveoli filled

with fluid

(drowning)

toxic

Blockade of breathing

Resp. centre depression

(opium, barbiturates)

Resp. muscle paralysis

(gelselmium)Reduced

capacity of Hb to bind O2

(CO poisoning)

Cyt. Oxidase inhibition

(cyanides)

ENVIRONMENTAL

Lack of o2 in air

(enclosed spaces, deep wells, high

altitude)

Exposure to irrespirable gases

(volcanic areas, heavily industrial

areas

TRAUMATIC

Pulmonary embolism from

DVT of leg following trauma

Pulmonary fat embolism from fracture of long

bones

Pulmonary air embolism from

incised wounds in veins like IJV

Bilateral pneumothorax

from stab injuries etc..

6)Postural asphyxia Seen in people made unconscious by heavy

alcohol intake or drugs

Lie in inverted posture pressure by abdominal viscera on diaphragm disables chest expansion death

7)iatrogenic Associated with deep anesthesia

Stages of asphyxia There are 3 stages lasting for 3- 5 minutes

before death occurs

• Resp. movements increase in rate & amplitude, slight cyanosis present

• Tachycardia; pulse rate & b.p. rises

1)Stage of dyspnoea

• Predominating expiratory efforts, face deeply congested, neck veins swollen, b.p. & pulse rate further increases

• Frequent convulsions occur followed by loss of consciousness and reflexes lost with pupils widely dilated

2)Stage of convulsions

• Resp. centre starts to get paralysed ,breathing is gasping, predominantly inspiratory with long intervals between

• b.p. falls, muscles relax, resp. stop & death occurs

3)Stage of exhaustion

Pathology of post asphyxial changes

anoxia

Anaerobic glycolysis

Accumulation of adenosine, lactic

acid & vasodilatation

Peripheral venous stasis , decreased

venous return

Decreased cardiac output

asphyxia

Asphyxial stigmata

Tardieu spots Petechial hemorrhages seen on the skin, mucosa, serous

membranes

Caused by capillary congestion giving rise to rupture of micro vessels ( esp. thin walled venules )

Seen above the level of strangulation

more commonly in areas where vessels are weekly supported ( subconjunctival, serous membranes , circum oral skin )

Occur as isolated hemorrhages or in large no. Sometimes combing to form red patches ( esp. at back of heart)

Usually round, dark & well defined ranging in size from pin’s head to 2 mm

Can also be seen in natural diseases (bleeding disorders, Addison's disease, inf. Endocarditis , some hematological malignancies , meningococcal septicemia, a/c heart failure) . These are general in their distribution.

Post mortem appearances Skin & subcutaneous

Oedema, cyanosis , Tardieu spots

Blood vessels

Congested , many ruptured & bleeding

Blood

Fluid & dark (rise in blood CO2 & fibrinolysin)

Larynx & trachea

Oedematous & contain bloody , frothy mucous.

May also contain the vomitus caused by medullary anoxia

Lungs

Congested, dark, oedematous , contain

transudated blood stained fluid

Abdominal viscera

Oedematous, congested, mucosa show petechial

hemorrhages

Brain

Congested & oedematous. Cranial sinuses filled with

blood

heart

Congested, edematous, may or may not be dilated

Serous membranes

Oedematous & show petechial hemorrhages

Causes of death as per autopsy findings

Natural causes with definite evidence

Cardiovascular causes

Coronary thrombus, atherosclerosis,

embolism resulting in MI

Aneurysms & their rupture, rupture of

fresh MI

CCF following c/c pressure & volume

hypertrophy cardiomyopathies

a/c Endocarditis

Inf. Endocarditis

a/c myocarditis

Cardiac & vascular malignancies

a/c pericarditis, cardiac tamponade,

constrictive pericarditis

Congenital heart diseases

Conducting system lesions causing

arrhythmias, heart blocks

Shock (hypovolemic,

cardiogenic, septic)

Fatty degeneration of heart ( anoxic, toxic ,hereditary)

Valvular lesions (stenosis,

regurgitation, prolapse )

c/c hypertension & associated

cardiovascular diseases

Pulmonary embolism

Heart failure secondary to

pulmonary diseases (cor pulmonale)

Systemic embolisation

Respiratory causes

Massive hemoptysis in cavitory T.B

Advanced lobar & broncho pneumonia

Advanced lung abscess bronchiectasis

Laryngospasm & oedema

DiphtheriaMalignancies of bronchus

Severe a/c asthma & advanced exacerbated COPD

Pulmonary embolism & infarction , pulmonary

oedema

Pneumothorax, massive pleural effusion with pulmonary collapse

Myasthenia gravis, impacted food particles

CNS causes

Intracranial hemorrhage

causing infarction, compression

Brain abscess, status epilepticus

Brain tumors & malignancies

Cerebral thrombosis,

embolism , stroke

Meningitis, severe a/c polio

encephalitis

Massive hydrocephalus, massive cysts of

ventricles

GIT causesMassive hemoptysis

(peptic ulcer, malignancies,

esophageal varices)

Perforation of ulcers (peptic, typhoid,

amoebic, malignant)

Volvulus, intussusceptions of

bowel

a/c hemorrhagic pancreatitis, obstructive

cholecystitis

Intestinal obstruction, strangulated hernia,

paralytic ileus

Gastrointestinal malignancies

a/c appendicitis, bursting of liver

abscess, rupture of enlarged spleen

Typhoid, hepatitis , parasitic & bacterial

diarrhoea, dysentery

Hepatic cirrhosis, c/c malabsorption

syndromes,

Genito urinary causesc/c nephritis,

Septic shock post UTInephrolithiasis

Obstructive hydronephrosis,

pyonephrosis

T.B kidney

Malignancies of kidney, bladder,

prostate,testis, ovary, uterus, vulva

Rupture of ectopic pregnancy

Toxaemia of pregnancy

Massive Uterine hemorrhage in fibroids, malignancies, difficult

labour

Twisting of ovary, ovarian cyst or fibroid

Miscellaneous Complicated

Diabetes mellitus

Metabolic disorders

(ketoacidosis, uremia, alkalosis,

Na, K, Ca disturbances )

Endocrine (hyperthyroidism, Addison's disease)

Blood dyscrasias

Hemochromatosis, sever anaemia,

hemoglobin disorders

Cerebral malaria

Sudden death Person not suffering from any dangerous disease

injury, poisoning

Includes only death that is sudden or within 24 hours of onset

Incident : 10% of all deaths

No age is exempted

E.g. : MI in a person who’s not had any warning signs before

E.g. : sudden death in athletes due to fatal arrhythmias

Unnatural (violent) causes

Homicidal

Suicidal

accidental

Obscure causes No lesion is found at autopsy or if found its

too insignificant in explaining the death

Natural diseases

(death ppt by emotion, stress, vagal inhibition,

VF)

Biochemical disturbances

(uremia, hypokalemia)

Respiratory pigment disorders

(anemia, porphyria)

Endocrine disorder

(thyrotoxicosis, Addison's disease)

Concealed trauma

(concussion, self reduced neck injury, blunt injury to heart,

vagal inhibition)

Poisoning

(Narcotic poisoning, anaesthetic over

dosage, drug allergy, idiosyncrasy)

when gross , microscopic, toxicologic & lab investigations fail to reveal cause of death

Lack of trained doctor

Inadequate physical

examination

(drug addict, snake bite)

Improper internal

examination

(air embolism)

Improper toxicological

&lab investigations)

Inadequate history

(vagal inhibition,

status epilepticus)

Vagal inhibition (vaso vagal shock) Cause sudden death in susceptible individuals

following minor trauma

Vagal inhibition causes fatal bradycardia & hypotension

leaves no evidence at autopsy

Proper history needed Carotid sinus

syndrome

Severe pressure on neck (hanging)

Blow on abdomen, testis ,chest, larynx

Insertion of instruments into

bronchus, uterus, bladder, rectum

Sudden distension of hollow muscular

organs

(criminal abortion)

Sudden evacuation of fluids (pleural &

peritoneal tap)

Extensive injuries to spine

Insertion of objects into auditory canal

Impaction of food in larynx

Unexpected inhalation of fluid

into upper resp. tract

Sudden immersion of body into cold water