Transcript death & post mortem changes

DEATH & POST-MORTEM
CHANGES
Mohammed Bader
5th year medical school
University of Jordan
DEATH
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Death is divided into two stages:
Clinical death:
it’s the Cessation of the function of 3 systems:
CVS, RS, CNS.
Cellular death:
cells no longer functioning or have metabolic activities or
aerobic respiration.
It’s follow the clinical death stage.
It’s depend on the blood perfusion to the tissue.
Different tissue die at different rate; cerebral cortex
tolerate only few minutes of anoxia while connective tissue
and muscles may survive longer (for hours).
Somatic Death (Brain death)
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the person is irreversibly unconscious, not aware of
surrounding environment and he is unable to appreciate
sensory stimuli or initiate any voluntary movement
Reflex nervous activity may persist and circulatory and
respiratory function continue either spontaneously or with
artificial support.
Somatic death= brain death = vegetative state
(all tissue and cells of the body are alive and functioning
except for those damaged in the CNS)
INDICATIONS OF DEATH
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Indications of death:
Unconsciousness
– Loss of all reflexes
– No reaction to painful stimuli
– Muscular flaccidity
– Cessation of heart beat and respiratory movement
– Eye signs:
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loss of corneal and light reflexes
Mid dilated position of the pupils
Irregular size and shape of the pupils
Eyelids usually closed incompletely
Tache noire: where the sclera remains exposed, two
triangles of discoloration appear at each side of the cornea,
either brown or black.
TACHE NOIRE
APPARENT DEATH
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a state that mimics death, occurs in:
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Electrocution
Hypothermia
Sun stroke
Drowning
Drug over dose (barbiturates)
Head injury
RIGOR MORTIS
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One of the recognizable signs of death that is caused by a chemical
change in the muscles after death, causing the limbs of the corpse to
become stiff and difficult to move or manipulate.
Death cessation of respiration depletion of oxygen used in the
making of ATP ATP no longer provided to operate the SERCA
pumps in the membrane of the sarcoplasmic reticulum, which pump
calcium ions into the terminal cisternae Calcium ions diffuse from
the terminal cisternae and extracellular fluid to the sarcomere  Ca
binds with troponin  crossbridging between myosin and actin
proteins.
Unlike normal muscle contractions, the body is unable to complete
the cycle and release the coupling between the myosin and actin,
creating a perpetual state of muscular contraction, until the
breakdown of muscle tissue by digestive enzymes during
decomposition.
Causes of rigors mortis are: ATP depletion (glycogen store depletion),
actin-myosin interaction and lactic acid accumulation.
RIGOR MORTIS (CONT’D)
Sequence:
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Primary muscular flaccidity
2.
Generalized muscular stiffness
3.
Secondary muscular flaccidity
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RM starts to develop about 2-3 hrs after death
Usually it’s first detected in smaller muscle
groups such as those around the eyes, mouth,
jaw & fingers.
It resolves in the same order in which it develops.
It concludes around 36-48 hrs after death
FACTORS AFFECTING TIMING OF RM
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Environmental temperature:
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Cold and wet  onset slow, duration longer
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Hot and dry  onset fast, duration shorter
Muscular activity before death:
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muscles healthy and robust, at rest before death  slow onset, duration longer
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muscles exhausted/ fatigued  onset rapid, esp in those limbs being used (eg in
someone running at time of death, lower limbs develop RM faster than upper limbs)
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increase activity (convulsions, electrocution, lightning)  rapid onset & short duration
Age:
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extremes of age  rapid onset
Health:
Cause of death:
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asphyxia, pneumonia, nervous de’s with muscle paralysis & dehydration  slow onset
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septicemia & poisoning  rapid onset, may even be absent, esp in limbs affected by
septicimia
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emaciated or died of wasting disease  rapid onset, short duration
RM: TIME ESTIMATION
Warm
Flaccid
Death < 3 hrs
Warm
Stiff
3-8 hrs
Cold
Stiff
8-36 hrs
Cold
Flaccid
Death > 36 hrs
RIGOR MORTIS (CONT’D)
RM in Iris:
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Antemortem constriction or dilation modified
May affect the eyes unequal, making the pupils unequal
RM in the Heart:
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Contracted, stiff LV may be mistaken for LV hypertrophy
RM in Dartos muscle of scrotum:
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Rigor in Dartos constricts testes and epididymis expulsion
of semen
Contraction of seminal vesicles and prostate
– Postmortem expulsion of semen
RM in Erector Pilli muscles attached to hair
follicles:
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Goose bumps, hair stands up
CADAVERIC SPASM
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Cadaveric spasm
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also known as instantaneous rigor, cataleptic rigidity,
or instantaneous rigidity
rare form of muscular stiffening that occurs at the moment
of death, persists into the period of rigor mortis and can be
mistaken for rigor mortis
the cause is unknown, but usually associated with violent
deaths happening with intense emotion
may affect all muscles in the body, but typically only
groups, such as the forearms, or hands
seen in cases of drowning victims when grass, weeds, roots
or other materials are clutched, and provides proof of life at
the time of entry into the water.
often demonstrates the last activity one did prior to death
and is therefore significant in forensic investigations, e.g.
clinging on a knife tightly
RIGOR MORTIS VS. CADAVERIC SPASM
Rigor mortis
Cadaveric spasm
Onset delayed after death (2-3
hrs)
Duration approx 12-24 hrs
Onset is instantaneous
Duration is a few hours, until it is
replaced by rigor mortis
Intensity comparatively
moderate
All muscles of the body are
affected gradually.
Intensity comparatively very
strong
Selected muscles, which were in
a state of contraction at the time
of death, are affected.
Cadaveric spasm in a drowning victim: had grass
from the river bank firmly clutched in the hand
CONDITIONS MISTAKEN AS RM
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Heat stiffness:
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Exposure of a body to intense heat (burning, high
voltage electrocution, etc) coagulation of muscular
proteins  muscular shortening, with flexion in the
upper limb, giving the apperance of pugilistic
attitude.
Cold stiffness:
Exposure of the body to extreme cold (<-5⁰C)
solidification of subcutaneous fat and muscles,
freezing of synovial fluid in joints
– Rigor mortis is only postponded, and after warming
the body, the rigor mortis will supervene.
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MEDICOLEGAL IMPORTANCE OF RM
Time estimation
 Cause of death
 Know position
 Sure sign of death
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HYPOSTASIS/LIVOR MORTIS
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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 discoloration will be pale.
starts immediately after death.
apparent after 0.5-1 hr and fixed after 8 hrs.
may not appear at all especially in infants, old
ppl and anemic ppl.
HYPOSTASIS (CONT’D)
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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
SITES OF HYPOSTASIS
Depends on the position of the body before
death:
 Supine:
shoulders, buttocks
 heels pressing against surface give white color
(pale).
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 Vertical
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(hanging):
distally in legs & feet.
 Drowning:
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chest, upper chest, and upper limbs.
 Face-down
death:
as in epilepsy, drunken victims
 whitening around nose & lips.
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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.
COLOR OF HYPOSTASIS
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The color of hypostasis is variable and depends
on the state of oxygenation at death.
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Usual color is blue-pink
It’s a crude indicator of the mode of death:
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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)
MEDICO-LEGAL IMPORTANCE OF
HYPOSTASIS
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Sure sign of death
Cause of death
Time estimation
Position before/ after death
Indicate if the body was moved or not after death
BODY COOLING/ ALGOR MORTIS
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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.
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In practice the temperature is either measured per rectum or
intra-hepatic via an abdominal stab.
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The rate of body cooling:
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1C/hr in summer
1.5C/hr in winter.
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.
 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.
POST-MORTEM DECOMPOSITION
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Turning the tissue of the body into fluids and
gases by the effect of bacteria and enzymes
starts immediately after death at the cellular
level
becomes visible in 48-72 hrs.
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 welchii predominates (same bacteria
that causes gas gangrene)
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The speed of decomposition depend on:
amount of bacteria in the body.
Temperature: Rapid putrefactive changes may
been seen in corpses left in a room which is well
heated.
Humidity: A high environmental humidity will
enhance putrefaction.
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.
MUMMIFICATION
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Occurs as a result of exposure of the body to high
temperatures and dry air currents, to a degree that
decomposition will stop.
The body will be Dry, Shriveled up and brown in color.
The Optimum Conditions for Mummification  dry &
warm climate.
Once the changes are complete, the body will remain in
that condition indefinitely.
No growth of micro organisms.
The time required for complete mummification can’t be
precisely stated but it takes several weeks to months,
depending on the size of the body and atmospheric
conditions.
MEDICO-LEGAL IMPORTANCE OF
MUMMIFICATION
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Identification
Time estimation
Cause of Death
Can detect abnormal pathology inside deep
organs
ADIPOCERE
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a grayish-white postmortem matter
caused by fat decomposition, which
results from hydrolysis and
hydrogenation of the lipids (fatty
cells) that compose subcutaneous fat
tissues.
 The optimum conditions for the
formation of adipocere:
1. Moisture
2. Warm environment
MEDICOLEGAL IMPORTANCE OF
ADIPOCRERE
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Preserve the body which can permit
identification after death.
It may give conclusions about the cause of
death.
It indicates that the time interval since
death was at least weeks to several
months.
The End.