DeathDr. Aamir Farooq

M. Phil. Pathologydr.aamirfarooq@hotmail.com

Death• Thanatology

• Cessation of all physiological processes or complete and permanent cessation of circulation and respiration is called Death.

Levels of death• Cellular:

Individual death of cells of tissues • Somatic:

Individual animal death (irreversible cessation vital organs)

Modes of death • Coma:

Cessation of function of brain • Asphyxia:

Cessation of function of lungs • Syncope:

Cessation of function of heart

Coma• It is a state of unconsciousness from which the patient cannot be aroused, even by powerful

stimulation.• failure of brain function • Etiologya) Traumatic injury to the brain.b) Accidental collision of animal .with any objectc) Falling of animal from height.d) Fighting with other animals.e) May be caused by cerebral hemorrhages, thrombosis, embolism ,tumors ,abscesses and

other inflammatory conditions of brain.f) Intoxication with certain chemicals such as CO and barbiturates.g) Presence of parasites such as Coenurus cerebralis

Asphyxia• Death due to failure of function of lungs and may be due to lack of O2

in respired air resulting in hypoxia.• Etiology:a) Mechanical obstruction in the respiratory tract .e.g., tumor,

inflammation, choke, anaphylactic reactions.b) Lungs disease or pulmonary circulatory disturbances.c) Strangulation (closure of respiratory passages from external

pressure on neck)d) Inhalation of irrespirable gases e.g. CO, SO2, H2S, NO.

Signs of Death

• Immediate signs (Postmortem changes)

• Early signs (Early hours postmortem changes) (12-24 hours)

• Late signs (Late postmortem changes) (after 24 hours)

Immediate SignsA. Insensibility• Don’t conclude death• Vagal inhibition, drowning.• Loss of EEG for continuous

5 minutes

Cont….B. Cessation of CirculationAuscultation….. 5 minutesAbsence of pulse in arteries ECG absence…. 5 minutes

Cont…..

• C. Cessation of Respiration

• Auscultation… Respiratory Sounds

• Movement of chest and abdomen sounds…5 minutes

Early Signs

• Cooling of body (Algormortis) • Changes in eye and skin • Postmortem lividity (livormortis )• Primary flaccidity• Rigormortis• Secondary flaccidity

Cooling of Body• More accurate in the first 24 hours after death• Heat production stops…….loss…..conduction….convection…..radiation• Factors• Body own temperature• Temperature of the environment• Size of the animal, subcutaneous fat, fur coat.• Exposed surface of the body, radiating heat to the environment.• Movement and humidity of air• Immersion in water

Cont...• These temperature assessments are made on the basis of body core

temperature.• After death, intra-abdominal temperature is directly measured for

assessment……per rectum or intrahepatic.• Oral and axillary temperature should not be used.• The normal rate of cooling is 1.5 degree 0F loss/ hour at 75 oF

environmental temperature.• Take two readings in an hour to get rate of cooling.

Changes in eye and skin • Soon after death, glistening

appearance of the eye is lost.

• Cornea becomes dry, cloudy and opaque.

• Corneal reflex loss.• Change in skin colour is not

so profound in animals , but elasticity is lost.

Post-mortem Lividity

• This refers to discoloration of body due to gravitational blood settling after the heat stops.

• Within about 30 to 60 minutes of death, the blood in coagulable due to release of fibrinolysin from small vessels

• This help us to determine the position of the body after death.

Cont…• 20 to 30 minutes ……….dull red patches which deeper in intensity with

increasing time.• Differentiation of lividity from bruising can be made by incising the

skin.• Lividity becomes perceptible between half hour after death……well

developed in next 3 to 4 hours and attain its maximum between 8 to 12 hours of death.• Typically lividity has purple or reddish purple coloration.

Primary Flaccidity

• In ordinary circumstances, muscles relax immediately after death.• Muscles become flabby and joints become flexible.• This condition persists for a few hours.• During this, muscles react to electrical and mechanical stimuli.• Pupil of eye responds to atropine and physostigmine.

Rigor Mortis• Stiffening and contraction of all

voluntary and involuntary muscles

• Rigor mortis appears in small muscles of the eyelids, lower jaw and neck,followed by limbs, involving first the small distal joints and then the large proximal joints of knees,elbow,shoulder and hips.

Rigor Mortis Mechanism

MechanismAnoxic Tissue Anaerobic

Glycolysis

Lactic acid production

Glycogen Depletion

ATP Depletion Actin-myosin cross bridge formation

No detaching due to ATP depletion

Cont…

• The gradual disappearance of Rigor mortis is due to suffer of coagulated proteins by autolytic fermentation

Factors

Temperature

Cold temperature Inhibits rigor Slower onset and slower progression of rigor

Warm temperature Accelerates rigor Faster onset and faster progression

Activity before death Anaerobic exercise Accelerates rigor Lack of oxygen to muscle, lactic

acid, and higher body temp accelerates Rigor Mortis

Body weight Thin Accelerated rigor Body loses oxygen quickly and body

heats faster

obese Slow rigor mortis Fat stores oxygen

Secondary flaccidity

• It is the relaxation of muscles with decline of rigor mortis.

• Rigor mortis passes of in some order in which it develops.

• All the body muscles become soft and flaccid.

• Muscles do not respond to electrical or mechanical stimuli.

Late Signs

• Putrefaction

• Adipocere

• Mummification

Putrefaction

• Putrefaction is post mortem destruction of soft tissues of the body by the action of bacteria and endogenous enzymes both.

a) Change in tissue b) Change in color c) development of gases d) liquefaction

Cont...• Environmental temperature has great influence on the rate of

development of putrefaction.• Putrefaction is optimal at temperature ranging between 70-100oF (21-

38oC) and is retarded when temperature falls below 50oF (10oC).• Greater humidity will increase putrefaction rate.• Putrefaction starts from death and is completed in almost 1 week

after which there is soft and putrefied viscera and body muscles can be seen.

Adipocere

• Saponification or adipocere is a modification of putrefaction characterized by the formation of fatty tissue into yellowish, greasy, wax-like substance, with a sweetish rancid odor.• It is first developed in sub-cutaneous fat and rarely in visceral organs.• It can be seen at 2-3 weeks after death.• Warm, moist, anaerobic environment

Mummification• Desiccation of tissue • Leathery mass

tendons surrounding the bones

• This condition is seen in 3-4 weeks.

TIME SINCE DEATH CONDITION OF CARCASSLess than 1hour Body is warm2-3 hours Patchy lividity6-8 hours Lividity fully developed and fixed12 hours Rigor mortis present all over24-36 hours Rigor mortis receding or absent. Abdomen

distended with gases.

48 hours Trunk or thoracic area bloated, swollen discoloured face.

72 hours Body swollen and disfigured, hair loss, tissue soft and discoloured .

1 week Soft and putrefied viscera.

2-3 weeks Only dehydrated viscera i.e. adipose week

3-4 weeks Mummification5-6 weeks Only skeleton is present.

PROGRESSION OF CHANGES AFTER DEATH

Temperature of body Stiffness if body Time since death

Warm Not stiff Not dead more than 3 hrs

WarmStiff

Dead between 3 and 8 hrs

ColdStiff

Dead 8 to 72 hours

Cold Not stiff Dead more than 72 hours