Postmortem Changes- Late changes
Late changes
Putrefaction
It usually follows disappearance of rigor mortis. It results from breakdown of complex organic compounds into simpler forms by the action of bacteria, fungi, and protozoa etc.
Autolysis is an aseptic process where organic compounds are broken by the enzymes of the body.
The agent commonly responsible is Cl. welchii that causes hemolysis, liquefaction of postmortem clot, emboli, thrombi, breakdown of tissues and gas formation.
Immediately after death, there is breakdown of cell membranes and they also become permeable.
The fall in oxygen concentration and rise of hydrogen favors bacterial growth and their spread. Bacteria liberate several enzymes, one such enzyme is lecithinase liberated by Cl. Welchii that hydrolyses the lecithin, which is present in all cell membranes including the red blood cells. This enzyme is responsible for postmortem haemolysis of blood. During the process of putrefaction, the soft parts of the body are affected first, and the bones are affected much later.


Differences between ante mortem and
postmortem blisters |
|
Ante mortem blisters |
Postmortem blisters |
Line of redness is
present |
Not present |
Contain serous fluid
with albumin and chloride |
Contain air only |
Base of blister is
inflamed |
Base is dry and hard
|
Infection, pus, and
sloughing is present |
Not present |
(ii) Stomach and intestine: they show dark red to brownish patches first on the posterior wall and then on the anterior wall.
(iii) Liver: liver softens and becomes flabby in 12 to 24 hours in summer. Blisters appear on its surface in 24 to 36 hours. The liver assumes a “honeycomb” or “foamy” appearance due to formation of air bubbles.
(v) Prostate: it resists putrefaction for a very long time and this is the last organ to putrefy in males.
(vi) Uterus: Uterus is the last organ to putrefy in females.
Greyish paste like brain material due to decomposition
Medico legal Aspects: (i) Late sign of death (ii) It helps in calculating time since death (iii) It helps in identification as hair, teeth and bones resist putrefaction.
Changes after death (Estimation of
Postmortem interval or time since death) |
|
Within 1 hour of death |
Warm body with moist transparent cornea,
General muscular flaccidity, Cessation of circulation and fragmentation of
the blood columns in the retinal vessels |
Within 2 hours |
Body surface is cool to touch; Postmortem
lividity is developing in the dependent parts and in patches by 1-2 hours.
Cornea becomes hazy and intraocular pressure falls to zero. Rigor mortis will
appear in the eye muscles and at times in jaw muscles. |
Within 3-6 hours |
Tache noires on the surface of sclerae, well
developed hypostasis by 4-6 hours. Cornea becomes cloudy by 6 hours. |
Between 6-12 hours |
Eyeballs get shrunken into the orbits,
well-marked hypostasis and it is fixed by 6-8 hours, Rigor mortis is well
developed. |
Between 12-24 hours |
Rigor mortis will be in the phase of
disappearance. Greenish patch of discoloration is seen in right iliac fossa
by 12-18 hours in summers and in 24-36 hours it extends over chest, trunk,
and abdomen. Foul smelling gases may emit from the body. Eyeballs can bulge
out; face is swollen, and abdomen is distended. |
Between 24 -48 hours |
Rigor mortis passes off in summer within
20-24 hours and in winters it may continue up to 36 to 48 hours. Marbling of
skin and body features is bloated, tongue is protruded out, and postmortem
blisters will form over different body parts. Immature and mature maggots
appear. |
Between 48-72 hours |
Hair and nails become loose, prolapse of
rectum or uterus. |
Between 3-5 days |
Skull sutures separate, brain gets
liquefied, Nails, hair, tooth become loose and may fall off. Bones become
loose at their respective joints. |
Between 5-10 days |
Colliquative necrosis. Soft tissues get
changed into black mass separating from bony attachments |
Beyond 10 days -1 to 2 months |
Soft tissues including cartilage has fallen
off and only detached skeletal parts are left out and skeletonization is
likely to occur in 1-2 months. |
Certain bacterial enzymes liberated from decomposing protein are necessary for the hydrogenation of unsaturated body fats in to saturated firmer fats. Water is essential for the change as it takes part in the synthesis and removes glycerin formed during hydrolysis of fat. Moist conditions are necessary for adipocere formation though it has been seen in dry conditions also. It occurs rapidly in bodies submerged in water. In obese persons and mature new borne it is formed quickly. The adipocere formation is accelerated by heat and retarded by cold. In India it has been reported between 3-35 days.
Medico legal aspects: (i) Late sign of death (ii) Identification of individual is possible (iii) Nature of wounds and cause of wounds can be found out (iv) Time since death can be calculated.
Mummification
It is a modified form of putrefaction and is characterized by drying or shriveling of the tissue that is due to dehydration of the body constituents. When climate is dry and warm with a free circulation of air around the dead body, the putrefaction is inhibited.
It begins in the exposed parts of the body like face, hands etc. and then spread to other parts. The skin hardens, becomes leathery and adheres to the bones.
The external appearance in a mummified body is preserved thus helping in identification. As the wounds remain intact, the cause of death can be determined. Internal organ thickens and becomes deep brown.
The average time it takes is from few months to 1 year.
Medico legal aspects: (i) Late sign of death (ii) Identification of individual is possible (iii) Nature of wounds and cause of wounds can be found out (iv) Time since death can be calculated.
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