Written by Dr. D. Rao

Thanatology:
Deals with study of death in all its aspects.

Death Two Types

1. Somatic Death/Clinical/Systemic Death.
   (few minutes after death)
   It is the complete and irreversible stoppage of the circulation,respiration and Brain Function
2. Molecular Death
   (Few minute to hours)
   It is death of tissues and cells individually which takes place usually in 1-2hours after stoppage of vital functions.

Brain death

1. Cortical Death
2. Brainstem Death
3. Combination of a & b.

Medicolegal aspects of Brain Death:
It is the confirmatory sign of Death which is very vital for-

• Organ transplantation
• Criminal responsibility

Vegetative state:
In this the patient breathes spontaneously, has a stable circulation and shows cycle of eye opening and closing which may simulate sleep and waking, but is unaware of the self and the environment.

Stupor:
The patient appears to be asleep and shows little or no spontaneous activity, responding only to vigorous stimulation and than lapsing back to somnolence.
Beating Heart Donor:

After Brain stem death has been established the retention of the patient on the ventilator facilitates a fully oxygenated cadaver transplant.

Suspended Animation
In this condition signs of life are not found, as the functions are interrupted for some time or are reduced to minimum.However Life continues and resuscitation is successful in such cases.

Agonal Period.
It is the time between lethal occurrence and death. This period is variable and Various activity have been reportedly performed by the victim.

Cause of Death.
It is the disease or the injury responsible for starting the  sequence of events, which are brief or prolonged and which produced death. It consists of Two Parts First parts includes framed in the following order i.e. a).Immediate Cause, b) Antecedent Cause., c) Underlying Cause. Second Part includes other Contributing Causes directly or indirectly Leading to Death besides the Interval of onset of the Terminal symptoms and the Death .

Manner of Death.:
Is the way in which the cause of death was produced-Natural and Unnatural i.e.Accident,Suicide and Homicide.

Mechanism of death:
It is the physiological or biochemical disturbances, produced by the cause of death which is incompatible with life eg. Shock, sepsis, Metabolic acidosis and alkalosis,Ventricullar fibrillation,etc.

Modes of Death:
Asphyxia, Coma and Syncope

Changes in the Body after Death

 

A knowledge of the signs of death help to differentiate death from suspended animation. The changes which taken place may be helpful in estimation of the approximate time of death. the signs of death appear in the following order.

1. Immediate (somatic death)

1. Insensibility and loss of voluntary power
2. Cessation of respiration
3. Cessation of circulation

2. Early (cellular death)

1. Pallor and loss of elasticity of skin
2. Changes in the eye
3. Primary flaccidity of muscles.
4. Cooling of the body
5. Post-mortem lividity
6. Rigor mortis

3. Late (decomposition and decay)

1. Putrefaction
2. Adipocere formation
3. Mummification

SUSPENED ANIMATION
(apparent death): In this condition signs of life are not found, as the functions are interrupted for some time, or are reduced to minimum. However, life continues and resuscitation is successful in such cases. The metabolic rate is so reduced that the requirement of individual cell for oxygen is satisfied through the use of oxygen dissolved in the body fluids. In freezing of the body, or in severe drug poisoning of the brain, the activity of brain can completely stop and in some cases start again. Suspended animation may be produced voluntarily. Practitioners of yoga can pass into a trance, death-like in character. Involuntary suspension of animation lasting from a few seconds to half-an-hour or more may be found in newborn infants, drowning, electrocution, cholera, after anesthesia, shock, sunstroke, cerebral concussion, insanity, etc. The patient can be resuscitated by cardiac massage or electric stimulator and artificial respiration.

CHANGES IN THE SKIN:
Skin becomes pale and ashy-white and loses elasticity within a few minutes of death. the lips appear brownish, dry and hard due to drying.

CHANGES IN THE EYE:

1. Loss of Corneal Reflex:
2. Opacity of the cornea:
3. Flaccidity f the eyeball:
4. Pupils: Soon after death, pupils are slightly dilated, because of the relaxation of muscles of the iris. Later, they are constricted with the onset of rigor mortis of the constrictor muscles and evaporation of fluid. As such, their state after death is not an indication of their ante-mortem appearance. Occasionally, rigor mortis may affect ciliary muscles of iris unequally, so that one pupil is larger than the other. If different segments of the same iris are unequally affected, the pupil may be irregularly oval or have an eccentric position in the iris. The pupils react to atropine and eserine for about an hour after death, but they do not react to strong light. The shape of the pupil cannot be changed by pressure during life, but after death, if pressure is applied by fingers on two or more sides of the eyeball, the pupil may become oval, triangular or polygonal.
5. Retinal vessels: Fragmentation or segmentation [trucking] of the blood columns in the retinal vessels appear within minutes after death, and persists for about an hour. This occurs all over the body due to loss of blood pressure but it can be seen only in retina by ophthalmascope. The retina is pale for the first two hours. At about six hours, the disk outline is hazy and becomes blurred in 7 to 10 hours.
6. Chemical changes: A steady rise in the potassium values occur in the vitreous humour after death.