Notes Flashcards
SIDS: definition
- under 1
- remains unexplained after autopsy, death scene and clinical history
SIDS: characteristics
- Low ses
- male
- premature
- winter months
- most common in 1-2 months old
SIDS: mother characteristics
- single
- smoker
- high parity
- infection in pregnancy
- short inter-pregnancy interval
SIDS: mechanisms
- many diff causes, often multifactorial
- Act via a final common pathway of cardioresp failure
SIDS: risk factors
- prone sleeping
- cigarette smoke exposure
- covering the head
- overheating
SIDS: triple risk model
- predisposed infant
- vulnerable period
- external stresses
Bruising
- can’t be used for age estimation
- although, yellow bruise may be more than 18 hours old
- bruising can occur after death
Incised Wound
- longer than it is deep
- less likely to effect organs
- usually bleeding is serious complication
- if sharp, no bruising or abrasion around wound
Knife Injuries
- single edged blade said to give a V at one end of the wound and a blunt end at the other
Self Inflicted Wounds
- usually multiple
- No of premil trial or hesitance cuts
- throat, wrists, front of chest and abdomen, thighs
- uniform depth
- superficial or minor
- similar appearance, style and orientation
- injuries are grouped on the contralateral side to the patients handedness
- old healed scars in similar sites
FSSA Departments
- chem
- biology
- forensic pathology
- toxicology
forensic anthropology
- missing people
- recently deceased
- incomplete or partial remains
- DVI
Haemastix
- detection of blood
- strip used by doctors to test for blood in urine
Polilight
- can locate semen, saliva and blood
Sexual Assault
- 17% of women and 5% of men experience sexual assault
- 19% of adult women report to police
Process
- assessment
- control
- preservation
- examination
- interpretation
- recording
- collection
- case management
Factors that may influence the condition of the body
- fresh vs salt water
- tidal or non-tidal water
- presence of predators
- water temp
- clothing
- type of surface at the base of the water
Postmortem findings of drowning
- Washer womans hand
- Skin degloving
- Loss of pigment in skin
- bloating of the body
- Froth around nose and mouth***
- haemolytic staining of the aorta (fresh water)
- water in the stomach
- Haemorrhage in middle ears
Diatoms
- Microscopic algae
- Found in brain, kidneys and bone marrow
Burns: who is most effected?
- young children
- males (largely occupational)
- Older people
- aboriginal and torres strait island people
Key Chemicals in Drug Manufacturing
- Iodine
- Hypophosporous acid
- red phosphorus
Fresh water drowning
- absorbed in circulation (through osmosis): results in dilution of blood -> swelling and rupture of rbcs -> liberation of potassium -> death from hyprekalamemia
Salt water drowning
- water from blood into lungs -> thickening of blood -> failure of circulation
Immediate death due to burn injury
- direct thermal injury: fluid loss, hypovolemia, shock, acute renal failure
- thermal injury to airways
- inhalation of toxic gases
Delayed death due to burn injury
- ongoing fluid loss with shock and renal failure
- resp failure due to damaged resp epithelium
- sepsis
- pulmonary embolism
Hyperthermia: Predisposing factors
- extremes of age
- co existing illnesses
- drugs
- obesity
Hyperthermia: autopsy findings
- non-specific
- vitreous electrolytes can confirm renal failure and dehydration
- if the deceased is found shortly after death, a core bosy temp (along with environment temp) can assist the diagnosis
Fire: Postmortem findings
- presence of soot below the level of the vocal cords
- thermal injury of the epithelial lining of the vocal cords
- blood samples to detect levels of carboxyhaemaglobin (although can be effecting by other factors eg. smoking)
Mechanism of death during fire
- not usually due to burns
- usually exposure to products of combustion
- and/or inhalation of hot air/gases
Hypothermia: Predisposing Factors
- extremes of age
- sex: males more susceptible
- thin
- immersion of water
- alcohol: vasodilation -> increase heat radiation
Effect of Hypothermia
- ability to shiver lost
- cerebral function impaired
- ECG changes
- Pulse slows
- Cardiac arrhythmia
- Death
Hypothermia: autopsy findings
- cherry red lividity
- Pinkish discolouration over large joints
- Wischnewsky spots: gastric erosions of the lining of the stomach (not specific to hypothermia)
- Paradoxical undressing
- Haemorrhagic pancreatitis
- Pneumonia
- Acute tubular necrosis
- Myofibre degeneration/necrosis
Electrocution: effect depends on
- voltage
- available current
- alternating or direct current
- resistance
- path through body
Electrical lesion
- collapsed blister surrounded by a pale area then a red rim
- although if immersed in water, there may by no signs
- internally there are no characteristics findings in fatal electrocution
- ‘streaming of nuclei’ was thought to be characteristic but has been seen in other injuries too
causes of death: electrocution
- primary: cardiac (at least 40Amps), resp arrest, CNS effects
- Secondary: trauma, burns
SIDS autopsy findings
- 70% of cases: intrathoracic petechiae on the pleura, epicardium and thymus
SIDS: conclusions
- not ‘A’ disease with ‘A’ cause
- end point of a number of diff factors - external and internal
- these may be different for different babies
Laceration
- bruised and crushed margins
- tissue strands or bridges in depths of wound
Semi-automatic
- single bullet when trigger is pulled
Automatic
- fires bullets as long as its trigger is squeezed eg/ machine guns
Rifle
- long-barrelled with grove to give bullets spin
- more accurate and powerful than handuns
- can be single action, semi-automatic or fully automatic
Shotguns
- Smooth bore
- Similar appearance to rifle but doesn’t have rifling inside the barrel
- Shell contains one large projectile (slug) and pellets
Gunshot Injuries
- Discharging a firearm will result in formation of smoke, flame and gases of combustion
Forensic Odontology: services summary
- identification
- oro-facial trauma
- opinion on dental issues
- training
Dental Identification
- highly individual
- resist destruction
- existence of dental data
- rapid
- although, shouldn’t compare to photos of teeth
Coroner
- investigates deaths
- +/- an inquest
- determines cause and manner of death
Reportable Deaths
- Unexpected, unnatural, unusual, violent or known
- Death within 24 hrs of a surgical procedure or having an anaesthetic
- Death within 24 hours after being discharged from hospital or seeking emergency medical treatment
Causes of Asphyxia
- reduced oxygen in environment
- reduced air/oxygen intake
- reduced oxygen transport
- reduced oxygen utilisation by tissues
Reduced Oxygen in environment
- Displacement of oxygen: sewers and pits, suicide by inert gas
- Consumption of oxygen: sealed space and flash fires
- Altitude
Reduced air/oxygen intake
Obstruction/covering of mouth
Blockage of internal airways: choking, disease (acute epiglottis), compression of the neck (about 15kgs to collapse trachea)
Restriction of chest wall movement: crush, disease of muscles/nerves, drugs
Impaired lung function: pneumonia
Reduced oxygen transport
Cardiac failure
Anaemia
Poisoning of haemoglobin (CO)
Diagnosis of Asphyxia
- Special tests: O2 levels drop and CO2 builds up, poisons: CO, cyanide
- Post mortem examination: ‘quintet of features’ petechiae, cyanosis, facial congestion, fluid heart blood, right heart congestion - although not specific to asphyxia
- Diagnosis requires integration of scene, post-mortem findings and other tests (tox)
Throttling
- Manual strangulation
- compression of veins in the neck results in petechiae and congestion
- External: bruises on neck, fingernail abrasions, petechiae
- Internal: bruising in muscles and tissues of neck, fractures of hyoid bone (greater wings), thyroid cartilage (superior horns)
Hanging Features
- Complete suspension: if sufficient compressive force to compress arteries of neck there is no congestion - petechiae absent
- Low/partial suspension: if incomplete/less compressive force - petechiae may be present
Possible mechanisms of death in hanging
- Compression of veins causing congestion of head stagnating flow
- Compression of carotid arteries depriving brain of blood
- Compression of airway - considered less likely
- Displacement of larynx upwards, causing epiglottis ot be closed over larynx
- Carotid reflex
Carotid Reflex
- at point of bifurcation of carotid artery there is a receptor for BP
- External pressure may ‘fool’ sensor into thinking BP is high
- Pressure on the bifurcation can cause the heart to slow and BP to fall
- Some individuals have a very sensitive receptor area and pressure on both sides can stop heart
Crush Asphyxia
- Intense congestion upper chest, into neck and head with petechiae
- Disruption of superior vena cava
- Delineation line of crushing object may be seen
- Weight on body: prevents movement of chest - prevents breathing, compresses chest - impairs blood return to the heart
Smothering
- May see blanching of skin under area of object used to perform smothering
- May have injuries on mouth
- Typically no findings
Asphyxia: Key Points
- There are no specific signs of ‘asphyxia’
- Petechiae occur due to increased capillary pressure (congestion), not hypoxia
- ‘Asphyxial death’ covers a range of conditions, in some (eg. hanging) airway obstruction may not be the main factor
- Diagnostic tests exist for only a small no of specific conditions eg. CO poisoning
- Diagnosis often requires integration of scene, autopsy, other findings (eg. toxicology)
- A high degree of suspicion should be maintained in vulnerable groups
DVI: Phase 1 - The scene
- scene photographed
- positioning of bodies recorded
- human remains are labelled, recovered and transported
DVI: Phase 2 - post mortem
- body is photographed
- jewellery, clothes removed and photographed
- Examinations: pathology, dental, xray, DNA samples, fingerprints
DVI: Phase 3
- Antemortem Info retrieval
DVI: Phase 4
- Reconciliation
- Ante and post mortem info is matched for identification
- Primary identifiers: dental, fingerprints, DNA
- Secondary identifiers: physical evidence, property
Forensic Toxicology
- Detection: presence or absence of drug or poison
- Quantification: how much is there?
- Interpretation: what’s the significance?
Drug Metabolism
- ADME
- Phase I: adds a polar handle or removes a group
- Phase II: attaches a more water soluble polar group to the handle
Somatic Death
- Irreversible loss of sentient personality (unconscious)
- Reflex and other autonomic nervous systems still function
Cellular Death
- Tissues and cells are dead - no longer function or have metabolic activity
- Follow cardio-resp failure
Body Cooling after death
- Algor Mortis
- Loss of metabolic function -> temp drop
- except when temp is over 37
- children lose heat more quickly
- oedema and dehydration can effect cooling
Post Mortem Lividity
- Cherry red - CO poisoning
- Brown lividity- nitrate poisoning
- Develops 30 mins to 2hrs after death
- Fully developed 8 to 12 hrs
- Fixed at 18 - 24 hrs (a finger pressed will not cause blanching)
Rigor Mortis
- 20 mins in jaw and eyelids
- Usually 2 - 4 hours after death and is fully developed 6 - 12 hours
- Temp and mode of death effect the development
- high temp may speed up development
- Cool temp may allow rigor to persist
- wear off 24-50 hrs post mortem or when decomposition starts
Decomposition
- two processes: autolysis and putrefaction
Autolysis
- BD of cells and organs through an aspectic process by intracellular enzymes (lysosomes and hydrolases)
- Accelerated by heat, slowed with cold, stopped with frozen
- Organs rich in enzymes will autolyse quicker eg. pancreas, intestine and adrenal medulla (within hours)
Sequence of Putrefaction
- Due to bacteria and fermentation
- GI flora travel throughout body
- Green discolouration in right lower quadrant of abdomen (above caecum)
- Organisms BD haemaglobin into sulph-haemaglobin (green colour)
- Green spreads, body becomes distended
- Bacteria tend to colonise in venous system -> venous marbling
- Skin blisters and slippage
- Gas builds up in abdomen
- Pressure causes eyeball and tongue to protrude
Body Changes after Death
- body cooling
- lividity
- rigor mortis
- decomposition
- mummification
Insect Activity
- Maggots secrete proteolytic enzyme that speeds up tissue destruction
- Diff insects at diff stages of decomposition
- This can help determine time of death
- Also can give info as to location of body and if it has been moved at any stage
Putrefaction of Internal Organs
- Diff rates
- Even a body in advances stages of putrefaction can yield info on cause of death
- Brian is one of the first organs
Adipocere
- Waxy substance derived from body fat
- requires water to form
Mummification
- Warm dry or frozen environment
- caused by dehydration of the tissues
- common in newborn infants (small and sterile)
Acceleration of Post Mortem Changes
- hot, moist environment
- overweight, high fat content
- infection or sepsis
- illicit drugs eg. meth
- insulated by warm clothing or coverings
Deceleration of Post Mortem Changes
- Cold environment
- Scantily dressed/naked
- Stored in cooling apparatus shortly after death
Determining Time of Death
- Three sources:
- Corporal evidence (present in the body)
- environment and associated evidence (present in the vicinity of the body)
- Historical evidence (based on deceased habits, movements and daily activities)
Rate Method
- measuring a change produced by a process which take place at a known rate
Examples: - amount and distribution of rigor mortis
- change in body temp
- degree of putrefaction
Concurrence method
- comparing the occurrence of events which took place at known times with the time of occurrence of the event under investigation
Example: - wrist watch stopped by a blow during an assault
- the extent of digestion of the last meal
- reciepts
Nomogram Method
- most widely accepted method used to determine time of death based on body temp
Circumstances indication child abuse
- explanation not good enough
- changes the explanation
- low ses
- seeks attention late
- repeating injuries
Typical Injuries in Child Abuse
- Subdural haematoma
- fractures of skull, ribs, arms and legs
- Patterned skin lesions
- Injuries to abdominal organs
- Various ages on injuries
Shaken Baby Syndrome
- Subdural haematoma
- retinal haemorrhage
- no skull fractures
- no scalp injuries
- grip markings
- rib fractures
- vein injuries
- diffuse axonal injuries
Why are children vulnerable to being shaken?
- large head compared to body
- weak neck muscles
- skull base flat
- not completely myelinated
- high water content - less supportive tissue
- thin and soft skull
Child abuse: Burns/Scalds
- characteristic patterns: immersion, splash, contact
- cigarette burns: multiple, small round lesions
- contact burns: distinct patterns eg iron, stove, element
Child abuse: physical neglect
- Emaciation
- loss of fat
- hollow cheeks
- sunken eyes
- dry skin
- ‘little old man’
Autopsies in SA
- 1300 per year
- 53% natural causes
What can an Autopsy Achieve?
- Establish or confirm identity of the deceased
- Determine cause of death
- Determine the mechanism of death
- Determine manner of death
- Establish time/place of death
Prevalence SIDS
0.4-1/1000 live births
Tram track marking
Bruising along the edge of the weapon
Burns 1st - 3rd degree
1st: superficial blistering
2nd: full thickness
3rd: destruction of skin and underlying muscle, fat and bone
Forensic Assessment of Bites
- Swabbing for DNA is the most important
Suicide Stabbing
- Will usually take top off first
- If wearing clothes, could be a homicide
Contact Discharge of Gun
- Circular hole with abrasion collar +/- muzzle impression, no soot or burn
Close Discharge on Gun
- Burns of the skin and hairs, soot soiling, propellant tattooing and unburnt propellant flakes
Distant Discharge
- No soot or powder
Death from external causes
- accidents, homicides, suicides
- 6.1% of deaths in Aus
Males Death from external causes
- suicide - hanging
2. transport accidents
Female Death from external causes
- falls
2. suicide - self poisoning
Manslaughter
- Voluntary: diminished responsibility, loss of control, suicide pact
- Involuntary: gross neglect, unlawful or dangerous act
Role of Pathologist at Blast Scene
- Not really identification
- Description and prep of bodies
- Assessment of victimes
Identification in DVI
- Dental
- Fingerprint
- DNA (problem; ‘comingling’/contamination)
- Pathological
- Circumstantial
CSI Examination
Aim is to identify potential physical evidence
Dead before entered water
- Natural disease IHD
- Homicide
- Accident: water skiing
- Suicide: planned complex suicide
Hypothermia in Water
- Survival time at 6 degrees is estimated at .4-8.8hrs
- Water at 5 degrees will reduce body temp to 35 degrees (hypothermia) in around an hour
Drowning Mechanism
- When immersed in water breath holding
- Then gasp and hyperventilation - results in inhalation of water -> drowning
- Water disrupts surfactant -> collapse of alveoli -> hypoxia
Haemolytic Staining of Aorta
- Fresh water
- Attributed to haemolysis of RBCs
- Not always seen as when bodies not rapidly recovered postmortem changes lead to dark red colouration of the aorta
Drowning Tests
- Blood biochemistry: changes in potassium, sodium or chloride (unclear in literature)
- Vitreous biochem: increased sodium in vitreous in salt water drowning has been reported
- Diatoms
Poison Schedules
- Prescription: S4
- Dependence: S8- meth, morphine, cocaine
- Prohibited: S9 - heroin, LSD, MDMA, cannabinoids
Fantasy
- GHB, GBL, NaGHB
Indoles
- LSD, magic mushrooms
NPS
- range of drugs generally not explicitly listed in the regulations
- ‘Designer drugs’
- Chemical structure are similar to many controlled drugs
- Limited data on dosage levels and the effect of abuse (both short and long term)
- Users unaware of what they are consuming
- Difficulty in treating overdoses
Types of Hyperthermia
- Classic: prolonged or extreme environmental exposure eg. heat waves, saunas, children in cars
- Exertional: extreme exertion eg. marathon runners, labourers, military
Hypothermia Definiton
Below 35 degrees
Hyperthermia Definition
Above 40.5 degrees
Investigation of Sudden Death
- History
- Scene
- Postmortem examination: internal, external, other eg. histology, tox
Haemopericardium
- Pericardial sac filled with blood -> heart can’t beat
- Causes: ruptured MI or ruptured dissection of the aorta
Cardiomegaly
- Cardiac enlargement
- Hypertension
Myocarditis
- ‘flu like illness’
- Inflammation of the heart
- Mainly viral