D EATH & P OST -M ORTEM CHANGES Mohammed Bader 5 th year medical school University of Jordan.

DEATH & POST-MORTEM CHANGESMohammed Bader

5th year medical school

University of Jordan

DEATHDeath 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)

• 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

• Indications of death:– Unconsciousness – Loss of all reflexes– No reaction to painful stimuli– Muscular flaccidity– Cessation of heart beat and respiratory

movement– Eye signs:

• 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

a state that mimics death, occurs in: Electrocution Hypothermia Sun stroke Drowning Drug over dose (barbiturates) Head injury

RIGOR MORTIS• 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:1. Primary muscular flaccidity2. Generalized muscular stiffness3. Secondary muscular flaccidity

1. RM starts to develop about 2-3 hrs after death 2. Usually it’s first detected in smaller muscle

groups such as those around the eyes, mouth, jaw & fingers.

3. It resolves in the same order in which it develops.

4. It concludes around 36-48 hrs after death

FACTORS AFFECTING TIMING OF RM  Environmental temperature:

Cold and wet onset slow, duration longer Hot and dry onset fast, duration shorter

Muscular activity before death: muscles healthy and robust, at rest before death slow onset, duration longer 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) increase activity (convulsions, electrocution, lightning) rapid onset & short

duration

Age: extremes of age rapid onset

Health:

Cause of death: asphyxia, pneumonia, nervous de’s with muscle paralysis & dehydration slow

onset septicemia & poisoning rapid onset, may even be absent, esp in limbs affected by

septicimia 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: • Antemortem constriction or dilation modified• May affect the eyes unequal, making the pupils unequal

• RM in the Heart: • Contracted, stiff LV may be mistaken for LV hypertrophy

• RM in Dartos muscle of scrotum: • 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:

• Goose bumps, hair stands up

CADAVERIC SPASM• Cadaveric spasm

– 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 instantaneousDuration is a few hours, until it

is replaced by rigor mortis

Intensity comparatively moderate

Intensity comparatively very strong

All muscles of the body are affected gradually.

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

• Heat stiffness:– 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.

MEDICOLEGAL IMPORTANCE OF RM

Time estimation Cause of death Know position Sure sign of death

HYPOSTASIS/LIVOR MORTIS

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)

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). 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.

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

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)

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

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.

FACTORS AFFECTING RATE OF COOLINGSurface 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

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)

The speed of decomposition depend on:1. amount of bacteria in the body.2.Temperature: Rapid putrefactive changes

may been seen in corpses left in a room which is well heated.

3.Humidity: A high environmental humidity will enhance putrefaction.

4. 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.

MUMMIFICATIONMUMMIFICATION 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

• Identification• Time estimation• Cause of Death• Can detect abnormal pathology inside deep

organs

ADIPOCERE

is 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.Moisture2.Warm environment

MEDICOLEGAL IMPORTANCE OF ADIPOCRERE

• 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.