Death

DEATH AND its MEDICOLEGAL

ASPECT

Death :-definition , types ,changes after death, classification & role in

deciding time since death.

Definition• In simpler times, death was defined as the

permanent cessation of cardiac and/or respiratory function.

• Today, instrumentation can keep a heart beating and an individual breathing in spite of the fact that if this machinery were turned off, heart and respiratory

activity would cease. This has brought about the concept of brain death.

Clincally death is defined as the irreversible cessation of life.

TYPES OF DEATH

For the purpose of understanding about death and its mechanism , it is divided into two

types :- Somatic death. Molecular death.

SOMATIC DEATHSomatic death is defined as the irreversible

cessation of Functioning of brain Heart Lungs This results in complete loss of sensibility and

ability to move the body. However , certain body parts such as muscles can still be made to respond to electrical, themal or chemical stimuli suggesting the reality that death has not resulted completely

EXPLANATION

In somatic death , life has though ceased in the body as a whole, it still persists in its component parts , namely the tissues and cells.

Somatic death is diagnosed by three facts Cessation of heart beat :auscultation of the cardiac area for

the presence of heart sounds by a stethoscope continuously for 5 minutes. A flat ECG may also confirm this.

Cessation of breathing : by thorough auscultation of chest for breath sounds.

Cessation of brain activity : by a flat EEG. thus somatic death is declared when these three vital organ or

the Tripod of life fail to do their function.

DIFFERENTIAL DIAGNOSIS

Somatic death resembles to certain conditions like

Suspended animation.Coma following excessive dose of hypnotics or

sedatives.Hypothermia in old age.

MOLECULAR DEATH

• Somatic death ultimately terminates into molecular death.

• Molecular death is defined as the ultimate death of all cellular elements.

Explanation After somatic death , various tissues survive till

the oxygen supply to then is adequate. When the oxygen reserve in the cell gets depleted cellular death or molecular death sets on.

Suspended AnimationIt is a condition in which the vital functions of the body

are at such a low level that they cannot be appreciated by clinical examination

Apparent death

This may last few seconds to minutes. Voluntary- by yogis

Involuntary – drowning, electrocution, heat stroke, typhoid fever etc.

Early Changes

• Changes in the eye

• Changes in the skin

• Cooling of the body/Algor mortis

• Post mortem lividity/Hypostasis

• Rigor mortis/Cadaveric rigidity

Changes in the eye•

Corneal Changes;• Loss of Clear Glistening• Dry, Cloudy and opaque• Loss of reflexes• Light reflex abolished• Intra Ocular tension falls, eye balls become flaccid and sink in

the orbit• Blood flow in the retina becomes dotted and segmented look.

• Optic disc looks pale.

• Pupils fully dilated in the early stage and constict later due rigor mortis.

• Brownish discolouration of the sclera due to cellular debris and dust.

Changes in the Skin

• Loss of its translucency• Pale and Ashy white appearance• Loss of Elasticity• Wounds will not gape if it is inflicted after

death• Wounds caused during life will retain their

characteristic features.

Cooling of the body• Imbalance between heat production and heat

loss.

• Loss of heat of body by means of conduction convection and radiation, till it balances with the temperature of surroundings.

• Rate of cooling is fast during first few hours and later slows.

- CONDITIONS IN WHICH BODY TEMP RISES

- Sun stroke and pontine haemorrhage, disturbed heat regulating mechanism.

- Tetanus and strychnine poisoning, due to increase in heat production in the muscle.

- Acute bacterial or viral infection, lobar pneumonia, typhoid fever, encephalitis, etc.

- Intense asphyxial conditions- rise of temp by 2-3 c at death

“ Postmortem Caloricity”

The rate of cooling of the body is modified by the following conditions;

• Age• Condition of the body• Mode of death• Surroundings• Environmental temperature

Postmortem Lividity

It means discolouration or staining of the skin and organs after death due to accumulation of fluid blood in the dependent parts of the body.

Post mortem staining/Hypostasis/Suggilation/ Vibices/ Livour mortis.

1- 3 hr. Starts6-8 hr. Fixes.

• Commencement of Lividity

• Development of lividity

• Fixation of lividity

• Site of distribution

• Pattern

• Extent

• Difference between lividity and bruise.

Medico-Legal Importance

• It is a reliable sign of death• It gives the information about the position of

the body at the time of death• Time since death can be estimated• Colour suggest the cause of death• Distribution of lividity may give the

information about the manner of death

Changes in the Muscles

• Primary relaxation/ Flaccidity

• Rigor mortis/Cadaveric rigidity

• Secondary relaxation

Primary relaxation

Starts immediately after death with generalised relaxation of muscle tone:

• Dropping of lower Jaw• Eye balls lose their tension• Pupils are dilated• Joints are flabby• Smooth muscle relaxation- incontinence of

bladder.

Rigor Mortis/ Cadaveric rigidity :It’s the postmortem stiffness or rigidity of the

muscles after death

mechanismMainly due to fusion of Myosin and Actin

Time of Onset :Temperate climates – 3-6 hoursTropical climates – 1-2 hours• Rigor mortis generally occurs when body is

cold.• Not related to action of nerves• Develops in paralysed limbs also• First appear in involuntary muscles• Last to be affected finger and toes muscles.

Duration :

* Temperate climate – lasts for 2-3 days.• Tropical climate – 24 – 48 hours in winter 18 - 36 hours in summer• In general – 1-2 hours sets on for , 12 hours develops for - 12 hours maintaines and after 12 hours passes of

Circumstances modifying the Onset and Duration of Rigor mortis.

Age- Rigor – Mortis is very rare in premature infants. Rigor –mortis is slow in adolescent and healthy adultsMuscular conditon and activity before death.Onset is slow and duration is longer in muscular

and healthy body at rest.

Conditions Simulating Rigor-Mortis

• Heat Stiffening• Cold Stiffening• Cadaveric Spasm

Secondary Relaxation :• Muscles become soft and Flaccid• Do not respond to a mechnical and electrical

stimulus.

Late Signs Of Death

• Decomposition / Putrefaction.

• Adipocere formation / Saponification.

• Mummification.

Decomposition / Putrefaction• Last stage in the resolution of the body,from the

organic to the inorganic state, is a certain sign of death.

AUTOLYSIS• Rise of enzyme levels in the tissue cells after

death.• Softening & liquefying of the body tissue.• Starts 3-4 hrs after death and continues for 2-3

days.

BACTERIAL ACTION• Action of bacterial enzymes on tissue

components – carbohydrates/fat/proteins.• Bacterial growth – warmth,moisture are

conditions favourable.• Clostridium welchii, streptococci, E coli, B

proteus.

CHARACTERISTIC FEATURES

COLOUR CHANGES• Greenish discoloration of skin over caecum

and flanks after death appears 18-24 hrs.• Greenish to black discoloration-

‘Sulphmethahaemoglobin’ formed by H2S due to microorganisms in the large intestine.

• Appears early in summer & delayed in winter.

• Discoloration spreads- front of abdomen, external genitals, chest, neck, face, arms and legs – spreads whole body in 24-36 hrs.

• Discoloration of vessel walls due to pigmentation from decomposed blood over the shoulder and groin. Arborescent pattern- ‘Marbling’

GASES OF PUTRIFACTION• Development of gases under the skin and

hollow viscera 18-36 hrs. 24-48 hrs in solid viscera.

• H2S, ammonia, phosphated hydrogen, CO2 and methane.

• Causes pseudo rigidity, exerts pressure.• More gases accumulation, body floats in

water.

PRESSURE EFFECTS OF PUTREFACTIVE GASES• Displaces the diaphragm upwards.• Discolored fluid and liquefied tissue mixes with

gases producing froth.• Bloating of the features.• Shifting of the area of hypostasis.• Changes in skin, hair and wound.• Extrusion of fluid from the mouth and nose.• Emptying of the heart.• Changes in appearance of genitals.

• Early putrefaction 24-48hrs Larynx, trachea, brain of infants, stomach,

intestines, spleen, omentum and mesentery, liver and adult brain.

• Late putrefaction 2-3 weeks Heart, lungs, kidneys, bladder, esophagus,

pancreas, diaphragm, blood vessels, prostate, testis and non gravid uterus, ovaries.

ADIPOCERE

• Modification of the process of putrifaction in the dead body is (checked and is replaced) adipocere formation.

• Hydrolisation of fatty tissue into fatty acids.• Bacterial fat splitting enzymes and moisture

are essential – Lecithinase.

• Yellowish white, greasy wax with rancid smell.

• It forms at any site where fatty tissue is present.

• Time required, in summer-3 wks, in tropics-5 to 15 days.

• M.L.I. – - cause of death - time since death - place of death

MUMMIFICATION• It is a peculiar desiccation of a dead body

where by its soft parts shrivel up but retain the natural appearance and the features of the body.

• Rusty brown color, dry, leathery skin adherent to bones.

• Internal organs get transformed into a thick brown mass.

• Mummification occurs in bodies buried in shallow graves, in dry sandy soils.

• Time – 3 months to 1-2 yrs• M.L.I. – Identification - Cause of death - Time since death - Place of death

Time since death/ post mortem interval

• Point to be ascertained are; -cooling of the body -post mortem lividity -rigor mortis -decomposition changes- Contents of stomach and bowels- Contents of urinary bladder- Biochemical changes- Circumstantial evidence