Post Mortem Changes and Bodies from Water Flashcards
How long does it take for irreversible brain damage?
3-9 minutes
In the hospital, what four things are death determined by?q
- Cessation of breathing
- No response to pain or voice
- No pupillary response to light
- Cessation of pulse and heart beat
How many doctors establish brainstem death?
Two
What two organs show the most cellular resilience to hypoxia?
Bone and corneas (48 hours)
What two organs show the least cellular resilience to hypoxia?
Brain and spinal cord (4 minutes)
What do post mortem changes do to confirmation?
They confirm death. Resuscitation is futile.
What is Post Mortem Interval
Post-mortem interval (PMI) is the time that has elapsed since a person has died.
What colour will abrasions which occur in life be?
Red
What colour will abrasions that occur in death be?
Orange and parchmented
What sort of sites do animal artefacts occur in?
Exposed
What are these artefacts of:
Entry impact
Washerwoman change
Gooseflesh (Cutis anserina)
Artefacts of immersion
What is skin splitting an artefact of?
Fire and heat
What can extradural haematoma be an artefact of?
Fire and heat
What post mortem changres occur in hours?
Algor mortis
Livor mortis
Rigor mortis
What post mertem changes occur in days to weeks?
Putrefaction
What two post mortem changes occur after months?
Skeletonisatin
Mummification
Chill of death?
Algor mortis
Darkening of death?
Livor mortis
Stiffening of death?
Rigor mortis
What can be a useful indicator of PMI in the first 24 hours of death, only in temperate and cool climates?
Algor mortis
When assessing for algor mortis what method of determining core body temperature must you avoid in sexual cases?
Anal
When assessing for algor mortis what method of determining core body temperature could you use instead of anal?
Liver by subcostal stab- creates a wound
Loss of heat from the body due to conduction, convection and radiation. Little heat lost by evaporation
Algor mortis
Who will cool quicker- an obese individual or a thin person?
obese- larger surface area
What can there be a slight rise of temperature in after deatgh?
Decomposition
What is Henssge’s Normogram based on?
a mathematical cooling model
What does Henssge’s Normogram allow for correction of?
Body weight
Clothing
Drafts
Immersion in water
What does Henssge’s Normogram assume?
Normal body temp at death
No ariation in ambient temperature during cooling period
What are some exclusions to using Henssge’s Normogram?
- Near strong heat source
- Near cooling source
- Floor tiles
- Abnormal body temperature at death
- Body moved between death andtemperature reading i.e. fridge
How much faster does body cool in still water than air?
Twice as fast
How much faster does body cool in flowing water than air?
Three times as afast
Gravitational pooling of blood in blood vessels due to cessation of circulation in death
Livor mortis
Can you see livor mortis in internal organs too?
Yes
What is development of livor mortis delayed by?
Blood loss e.g. AAA, gastric ulcers and haemorrhage and poisoning
What happens to livor mortis at under 6 hours?
Incompletely formed, blanching, unfixed.
Primary pattern fades and secondary pattern develops according to new position.
What happens to livor mortis at 10-24 hours?
Well established, partially fixed- if moved from front to back will exhibit two patterns. Primary pattern fixed enough to remain, secondary pattern develops giving dual distribution.
What happens to livor mortis >24 hours?
Fully fixed, Primary pattern persists. No secondary patter ndevelops.
What does early lividity look like?
bLOTCHY SPOTS
Give two causes of bright pink lividity?
Refrigeration
Hypothermia (oxyhaemoglobin)
Give one cause of cherry pink lividity?
Carbon monoxide
Give one cause of scarlet lividity/
Cyanide
Give one cause of chocolate brown lividity?
Aniline dye
What causes vibices?
Rupturing of small blood vessels:
Intravascular hydrostatic pressure
PM weakening/breakdown of vessel wall
Where are vibices typically limited to?
Livid tissues
What causes rigor morits?
Muscle relaxation requires ATP to break actin-myosin bonds. ATP requires oxygen. Decrease in ATP post mortem means bonds cannot be broken causing rigor mortis. Also calcium build PM promotoes actin myosin cross bridging.
What is rigor superseded by?
Decomposition
Does rigor mortis involve smaller or larger muslces first?
Smaller- eye lids, jaw and neck
Hyperthermia at death does what to onset of rigor mortis?
Increases it
In what other situation does rigor mortis come on quickyl?
Muscle activity immediatley prior to death
Forenisc value of rigor mortis?
May indicate if body has been moved
pugilistic atitude?
Kneeling position PM when exposed to high temperatuer
What is the PM interval when: warm and without rigor?
less than 3 hours
What is the PM interval when: warm with rigor?
3 - 8 hours
What is the PM interval when: cold with rigor?
8-36 hours
What is the PM interval when: cold and without rigor?
> 36 hours
enzymatic breakdown of cells/tissues
Autolysis
Bacterial breakdown of cells/tissues
Putrefaction
What is maceration?
Type of decomp. Sterile autolysis of foetus in uterus.
What conditions does adipocere need?
Wet
What conditions does mummification need?
Cool and dry
What happens within two days of putrefaction?
Green discoloration of lower abdomen due to overgrowth of colonic bacteria
What happens within 3-4 days of putrefaction?
Greenish black discoloration and swelling of face and neck due to gas production from bacteria
During putrefaction what might extrude from the mouth?
Reddish brown purge fluid
How does marbelling occur during putrefaction?
Due to breakdown of haemoglobin within blood vessels- prominence of blood vessels on skin (days to a week)
Name four gases found in gaseous bloating during putrefaction?
Methane
Hydrogen
Hydrogen sulphide
Carbon dioxide
Who is mummication more common in?
Infants
What term is given to the transformation of body fat to oleic, palmitic and stearic acids by hydrolysis?
Adipocere- saponification
What are the causative bacteria for saponification?
Clostridium welchii
What prolongs gastric emptying?
Alcohol. Stress delays it.
State Casper’s Rule of decomposition.
At similar average temperatures, the degree of putrefaction in a body in open air for 1 week corresponds to that of a body immersed after 2 weeks or a body burried for 8 weeks.
Estimation of duration of immersion if wrinkled fingers, palsm and feetS?
12-30 HOURS
Estimation of duration of immersion if early decomp in head, neck, abdo and thighs?
4-10 days
Estimation of duration of immersion if Bloating of face and abdomen, venous marbling &
peeling of epidermis on hands and feet, scalp slippage:
2-4 weeks
Duration of immerstion if gross skin shedding, muscle loss and exposure of skeleton?
1-2 months
If body temp is at 34 what happens?
Loss of consciousness and aspiration of water
If body temp is at 28 what happens?
Ventricular fibrillation
If body temp is at 24 what haPPENS?
Asystole
What exacerbates circum-rescue collapse?
Cold water and vertical rescue
Explain 3 steps in drowning in fresh (hypotonic water). Death in 4-5 minutes
- Water absorbed from airways into circulation- hypervolaemia
- Na diffuses from circulation into lung fluid- hyponatraemia
- RBC swell and burst (haemolysis)- raised blood K leading to VF
Explain the two steps of drowning in salt (hypertonic) water. Death 8-10 minutes
- Water diffuses from cirulation into lung fluid- reduced blood volume nad increase blood concentration
- Na and Cl diffuse from lung fluid in to circulation - raised blood Na
What is the mechanism of instantaneous drowning?
Reflex cardiac arrest (vagal inhibition)- triggered by cold water in nasal passages, sensation of myocardium by adrenaline and/or alcohol
Skin maceration or washerwoman change occurs after how long in warm and cold water?
wARM- minutes
Cold- 4-5 hours
Are there diagnostic features of drowning?
There are none.
What are these signs suggestive of:
Foam in airways
Emphysema aqueosum
Foreign material in airways and stomach
Middle ear haemorrhage
Drowning
Champignon de mousse
Foam in airways suggesting pulmonary oedema. Only found in freshly drowned bodies.
In drowning id the lungs are voluminousl hyperinflated, overlapping and doughy?
Emphysema aqueosum
In drowning what is the term for blue disclolouartion in bony roof of middle ear (tube)?
Middle ear haemorrhage
What bruising is common in drowning?
Shoulder muscle bruising
Name 4 lab tests for drowning.
Specific gravity of blood in left ventricle.
Plasma chloride
Plasma magnesium
Diatoms