POST MORTEM CHANGES

Postmortem changes after death

Immediate Changes Early Changes Late Changes

Immediate changes

• Permanent Cessation of Brain function

• Complete Cessation of Circulatory function

• Entire and permanent cessation of Respiratory

function

Permanent Cessation of Brain function:

• Loss of Sensations; viz, touch, pain and temperature• Loss of reflexes• Total loss of E.E.G. Rhythem• Confirmation of Brain- stem death

BRAIN DEATH

Death of brain cell occurs earliest after stoppage of the circulation but the process of death may be initiated by the failure of the function of brain.

Classification: Cortical death Brain-stem death Both cortical & brain stem death

Brain –stem death:

• The patient must be comatose state at least six hours.

• No Abnormal Decorticate or decerebrate postures should be present

• All brain-stem reflexes must be absent.

• Pupils should be fixed• No Corneal reflex• Absent of the oculo-cephalic reflex• Absent vestibulo-ocular reflexes• No Motor responses• No Gag reflex• No Respiratory movements after test withdrawal

of ventilator for 30 sec.

Complete Cessation of Circulatory Function

• Magnus test• Finger nail test• Diaphanous test• Icard’s Fluorescein test• Heat test• Artery incision test• A flat E.C.G. for a continuous period of five

minutes

Entire and permanent cessation of respiratory function

• Mirror test• Feather test• Winslow’s glass water test.

SUSPENDED ANIMATION

It 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

• Facial pallor (pallor mortis)

• Changes in the skin

• Changes in the eye

• 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, becomes permanently hazy after

10-12 hrs.• 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 and slowely become hazy.

• Pupils fully dilated in the early stage and

constrict later due rigor mortis.

• Discoloration of the sclera which is initially

yellow and later turn brownish due to drying

and desiccation of the exposed conjunctiva

and the sclera underneath.

k/a Taches Noires Scleroitiques

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(ALGOR MORTIS)

• 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.

• Temperature is recorded by Chemical thermometer- Thanotometer 25 cms.

• Recording of temperature : Normal temp. – Rectal temp 4 inch above anus. Rate of temp. fall/hour• Variation of body temperature• There are some Conditions in which heat may be

retained or increased.

- 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 degree 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.

• 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:

• Drop of lower Jaw• Eye balls lose their tension• Pupils are dilated• Joints are flabby• Smooth relaxation- incontinence of Urine and

Faeces.

Rigor Mortis/ Cadaveric rigidity :

This phenomenon comes immediately after the muscles have lost the power of contractility and is irreversible changes in the muscles of the body, both voluntary and involuntary.

MyofibrilsMyosin and ActinAdenosine Triphosphate – A.T.P.

Time of Onset :Temperate climates – 3-6 hoursTropical climates – 1-2 hours• Rigor mortis generally occurs when body is cold.• Not related to nerves action• 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.

MANNER OF DEATH :

• In wasting disease and great exhaustion- cholera, plague, typhoid, T.B. Cancer etc. the onset is early and disappears soon.

• In diseases – Pneumonia, asphyxia and nervous conditions- onset is delayed Atmospheric condtions:

• In dry and cold air-onset slow and lost for long time. Warm and moist air onset is rapid and duration short.

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.

CASE SIMULATING RIGOR MORTIS BEFORE DEATH

A case of rigor mortis in a living patient occurring possibly due to severe vasoconstriction limiting blood supply to the muscles -Murali Chakravarthy, “Rigor Mortis” in a Live Patient; (Am J Forensic Med Pathol 2010;31: 87–88)

SOME POINT TO BE DISCUSSED IN RIGOR

Kobayashi et al have suggested that the onset and passing off of rigor mortis in various groups of muscles depends on the glycogen and lactic acid levels.They also observed that the glycogen level at death and 1 hour after death and the lactic acid level 1 hour after death in masticatory muscles were lower than in the leg muscles. It is possible that the differences in the proportion of muscle fiber types and in glycogen level in muscles influence the postmortem change in ATP and lactic acid, which would accelerate or retard rigor mortis of the muscles.

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 PUTREFACTION 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.

APPEARANCE OF MAGGOTS Flies lay eggs over the decomposed body-

nose, mouth, vagina and anus in 18-36 hrs. After 24-36 hrs eggs hatch into larvae or

maggots, enter the body and destroy the tissues.

After 4-5 days develop into pupae. After 7-8 days into adult fly.

OTHER SEQULAE Fall of teeth Separation of skull sutures Liquefied brain matter oozes out. ‘Colliquative putrefaction’ – this process

takes place between 5-10 days.

INTERNALLYSTOMACH Dark red patches over the walls Perforation due to autolysis

LIVER Softens and flabby Becomes spongy ‘Foamy liver’

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.

FACTORS MODIFYING PUTREFACTION EXTERNALWarmth and clothing Putrefaction begins at 10°C and occurs rapidly

at 37°C. Freezing point – bacterial growth inhibited and

putrefaction will not occur. Clothing hastens putrefaction initially and

protects against flies and insects.

Moisture Help in rapid multiplication of organisms. Bodies recovered from water if left in air,

decomposes rapidly.

Air 1 week in air = 2 weeks in water = 8 weeks

buried – ‘Casper dictum’

Manner of burial In air tight coffins, very little change of body for

long periods. Without coffins, putrefaction is very rapid. Bodies in deep graves putrefy very slow. Bodies buried in lime, decomposition is

retarded. Bodies in sandy and porous soils are conducive

to mummification.

INTERNAL FACTORS Age and condition of the body Sex Mode of death

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. Composed of saturated fatty acids by palmitic,

stearic, hydroxystearic, olic acids

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. – to establish the identity - 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

Important clue for investigation of time. It helps apprehend the person likely to be

involved. 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

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