Post on 18-Nov-2014
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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