P ost- M ortem C hanges Part 2

1. Post-Mortem Changes Part2 Rashed Dawabsheh

2. Hypostasis/Livor Mortis

3. Hypostasis/LivorMortis(lividityor suggilation) • after death occurs, circulation of blood ceases & subsequent movement of blood is by gravity • blood accumulates in the capillaries in the dependent parts of the body purple or reddish purple discoloration of the adjacent skin • in pressure areas such as the shoulder blades, buttock & calvesdiscoloration will be pale. • starts immediately after death. • apparent after 2 hrs and fixed after 8 hrs. • may not appear at all especially in infants, old ppl and anemic ppl.

4. Hypostasis (cont’d) • early hrs after death it appears in the form of blotchy post-mortem hypostasis which usually sinks down and becomes confluent on the most dependant area • once hypostasis is established, there is controversy about its ability to undergo subsequent gravitational shift if the body is moved into a different posture. • Primary hypostasis may either: • Remain fixed • Move completely to the newly dependant zone • Be partly fixed and partly relocated

5. Sites of Hypostasis Depends on the position of the body before death: • Supine: • shoulders, buttocks • heels pressing against surface give white color (pale). • Vertical (hanging): • distally in legs & feet. • Drowning: • chest, upper chest, and upper limbs. • Face-down death: • as in epilepsy, drunken victims • whitening around nose & lips. • Hypostasis may also occur in viscera: • Heart: mistaken for MI • Lungs: mistaken for pneumonia • Intestine: mistaken for hemorrhagic infarction

6. Distribution of Hypostasis If the body remains vertical after death as in hanging cases, hypostasis will be most marked in the feet and to a lesser extent the hands.

7. Color of Hypostasis • The color of hypostasis is variable and depends on the state of oxygenation at death. • Usual color is blue-pink • It’s a crude indicator of the mode of death: • Cherry-pink: CO poisoning • Dark blue-pink: cyanide poisoning • Brown: methahemoglobinemia • Bronze: septic abortion caused by Clostridium perfringes. • Pallor: anemia, hemorrhage (or normal in extremes of age)

8. Timing and Permanence of Hypostasis • Hypostasis appears at variable times after death • May appear half hr to many hrs after death • In the early hrs after death it appears in the form of blotchy post-mortem hypostasis which usually sinksdown and become confluent on the most dependantarea.

9. Hypostasis vs. Bruises (Ecchymosis) With a bruise, blood will not flow from the cut

10. Medico-legal Importance of Hypostasis • Sure sign of death • Cause of death • Time estimation • Position before/ after death • Indicate if the body was moved or not after death

11. Body Cooling/ Algor Mortis • the most useful indicator of time of death during the first 24 hours post-mortem. • after death all metabolic activity ceases rapidly (muscles, liver) & circulation stops  heat production ceases soon after death • The body surface begins cooling immediately after death, followed by delay in deep organs cooling, until a heat gradient is set up between the core of the body and the surface. • Delay “temperature plateau” • Plateau = variable: from minutes to 2-3 hours. • In practice the temperature is either measured per rectum or intra-hepatic via an abdominal stab. • The rate of body cooling: • 1C/hr in summer • 1.5C/hr in winter.

12. Factors affecting Rate of Cooling Surface area of the body: • larger surface area  speeds up cooling rate. • Children: increase surface area gives rapid heat loss. • Body weight: • Larger bw: slower cooling • Smaller bw: faster cooling • Edema: • slower cooling rate. • Clothing, posture and emaciation. • Environmental Temperature : • Higher humidity: rapid cooling rate • Rapid air velocity: rapid cooling rate • Water: • rapid cooling rate: • More rapid in flowing water than still water • If there is a fulminating infection, e.g. septicaemia, the body temperature may continue to rise for some hours after death.

13. Post-Mortem Decomposition

14. Post-Mortem Decomposition • Putrefaction • Mummification • Adipocrere • Skeletelization

15. Putrefaction • the normal final sign of death. • starts immediately after death at the cellular level • becomes visible in 48-72 hrs. • its onset may be sped up or delayed by several factors mainly: • temperature • humidity. • Two phenomena for putrefaction: • Autolysis: occurs by digestive enzymes released from the cells after death. • Bacterial action: most of them come from the bowel and Clostridium welchiipredominates (same bacteria that causes gas gangrene)

16. The 1st visible sign of putrefaction is green or greenish red discoloration of the skin of the anterior abdominal wall • normally starts in the right iliac fossa. • The next phase: • gas formation • blisters containing red fluid appear on the skin, mistaken as bleeding • Humidity, temperature, bacterial activity  body proteins break into polypeptides & amino acids • Brain &epithelial tissues are the 1st to be affected by putrefaction • Heart, uterus & prostate may survive for longer periods. • Military plaques: nodules in heart (epi/endocardial) • Marbling: bacteria colonize venous system hemolysis stain.

17. Marbling

18. Influences on Putrefaction • A high environmental humidity will enhance putrefaction. • The rate of putrefaction is influenced by the bodily habits of the decedent; obese individuals putrefy more rapidly than those who are lean. • Putrefaction will be delayed in deaths from exsanguination(bleeding to death) because blood provides a channel for the spread of putrefactive organisms within the body. • Conversely, putrefaction is more rapid in persons dying with widespread infection, congestive cardiac failure or retention of sodium and salts. • It tends to be more rapid in children than in adults, but the onset is relatively slow in unfed new-born infants because of the lack of commensal bacteria.

19. Influences on Putrefaction • Heavy clothing and other coverings, by retaining body heat, will speed up putrefaction. • Rapid putrefactive changes may been seen in corpses left in a room which is well heated, or in a bed with an electric blanket. • Injuries to the body surface promote putrefaction by providing portals of entry for bacteria and the associated blood provides an excellent medium for bacterial growth.