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Flashcards in Changes after death Deck (23):
1

Definition of somatic death

Death of the body
Cessation of respiration and circulation

2

Define cerebral death

Implies total destruction of the brain with loss of voluntary and reflex functions

3

Define irreversible coma

State of vegetation in which all functions attributed to cerebrum are lost, while vital functions are retained

4

Minimum criteria for brain death

- loss of spontaneous ventilation within 5 minutes of disconnecting ventilator
- lack of brain-stem reflexes
- rectal temp below 35
- any drugs in the last 12 hours that could affect ventilation or consciousness
- no doubt that cerebral state is due to irreversible cause

5

Brain stem reflexes that need to be tested

- pupil reaction to light
- pupil reaction to pain
- dolls eye moevement (cold caloric test)
- gag reflex

6

General physical changes after death

- pallor of skin
- muscle flaccidity
- contact flattening and pallor
- eye changes (pupils mid-position)

7

Body changes after death

- changes in fundus oculi
- post-mortem lividity
- rigor mortis
- digestion of undigested food
- environmentally induced changes

8

Three major early changes used to determine time of death

- cooling (algor mortis)
- stiffening (rigor mortis)
- discolouration (livor mortis)

9

Things that influence rate of cooling of a body

- environmental factors
- intrinsic factors (body build, nature of death)
- site of measurement (skin, sub-hepatic)

10

Pattern of temperature change

S-shaped
- initial plateau (1-3 hrs - heat produced by anaerobic glycgenolysis)
- falling straight line (3-12 hrs)
- slow-falling exponential curve

11

Average hours to environmental temperature in average conditions

- 28 for normal
- 41 for obese
- 19 for thin

12

Factors that can affect the rate of cooling

- air temp change
- water
- clothing
- poisoning
- septicaemia

13

Define rigor mortis

- the state of generalised muscle rigidity which follows primary flaccidity in all voluntary and involuntary muscles

14

Physiological mecanism of rigor mortis

Reduced ATP levels lead to chemical bonding between actin and myosin to for acto-myosin
- cause the muscles to become hard, still and a bit shortened

15

When does rigor mortis occur?

- small muscles 2-4 hrs
- obvious by 6-8 hrs
- fully established by 12 hrs
- passes by 24 hours

16

Things to differentiate from rigor mortis

- cadaveric spasm
- cold stiffening or freezing of joints
- heat rigor
- ankylosis of joints
- fat rigidity

17

Definition of post mortem lividity

- discolouration of the body after death due to gravitation of blood into the dependent capillovenous bed in the skin and subcutaneous tissues

18

When does post-mortem lividity usually occur?

- within 30 mins to 2 hours
- fully fixed at 8-12 hours

19

Medico-legal importance of lividity

- suggests positioning
- needs to be distinguished from bruising
- colour may suggest poisoning
- help estimation of TOD
- pressure effects must be differentiated from strangulation
- putrefaction sets in earlier in livid tissue

20

Late changes in the dead body

- autolysis
- adipocere
- mummificaiton

21

Describe adipocere

- hydrolysis and hydrogenation of body fat
- subcutaneous tissue becomes waxy when cold and oily when warm

22

Pathogenesis of adipocere

Clostridium welchii lecithinase activity on body fat
- formation of fatty acids which inhibit puterfaction
- associated with bodies in wet graves
- takes months

23

Other factors that can help estimating time of death

- animals (maggots)
- hair
- bones (C14)
- blood
- CSF
- Ocular fluid (vitreous potassium)
- gastric contents