Transcript ENVIRONMENTAL

ENVIRONMENTAL DEATHS
ELEMENTS
DROWNING
• QUESTIONS:
• WAS VICTIM ALIVE OR DEAD WHEN
IMMERSED ?
• ANY PRIMARY INJURY PRIOR TO
SUBMERSION?
• IF DEATH WAS DUE TO DROWNING,IS
IT ACCIDENT,SUICIDE OR HOMICIDE
DROWNING
• DEATH due to Cerebral Anoxia
• Voluntary Breath-Holding eventually
overcome by Involuntary Urge to Breathe
• LARYNGOSPASM in “Dry-Drowning”
• If no laryngospasm,large volumes of fluid
are inhaled and swallowed---may continue
until respiration ceases
DROWNING
• Hypoxia ---- Anoxia --- Brain Death
• Conciousness lost within 3 minutes
• Agonal Period -- vomiting (aspiration ),
defaecation,urination,seminal emission
Freshwater Drowning
• Hypotonic
• Large volumes of water pass through the
alveoli and increase the blood volume
• Haemolysis
• Pulmonary Surfactant denatured
Freshwater Drowning
• Hypotonic
• Large volumes of water pass through the
alveoli and increase the blood volume
• Haemolysis
• Pulmonary Surfactant denatured
Saltwater Drowning
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Hypertonic
Plasma drawn into alveoli by osmosis
Decreased Blood Volume
Haemoconcentration
Raised Blood Electrolytes
Dilutes and washes away Pulmonary
Surfactant
Loss of Pulmonary Surfactant
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Leads to Alveolar Collapse
Reduced Lung Compliance
Severe Ventilation/Perfusion Mismatch
Hypoxia
Near-Drowning
• First 24 hours after rescue
• Sudden Cerebral Oedema is a major cause
of death
Near-Drowning
• Survival beyond 24 hours after rescue
• May be Concious or Unconcious
• May develop Pulmonary
Oedema,Haemoglobinuria,Cardiac
Arrythmia,Pneumonitis,Fever,Sepsis
• Cerebral Hypoxia---convulsions,amnesia,confusion,coma
ICY WATER
• Survival possible after prolonged
submersion
• “DIVING REFLEX”---Bradycardia,intense
Vasoconstriction (except Brain and Heart)
WARM WATER
• Irreversible Cerebral Anoxia in 3-10
minutes
DROWNING
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AUTOPSY FINDINGS:
Findings are variable
Plume of frothy fluid in mouth and airway
Water in stomach
Evidence of Cerebral Oedema
The above are seen only in cases where
body is recovered soon after drowning
DROWNING
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AUTOPSY FINDINGS:
“Washerwoman changes”
Affects skin of hands and feet
Skin becomes shrivelled and pale within 1-2
hours
• Feature of Immersion---Not of Drowning
• Non-specific---cf wet clothing,mud etc.
Laboratory Tests for Drowning
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Diatoms --- Unicellular Algae
Present in water,soil,atmosphere
If circulation, enter lungs and other organs
Bone Marrow---Femoral
Digested with enzymes or detergents,obtain
centrifuged pellet
• Compare with water sample
• Reliability Questionable
Body in Water
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After death the body sinks
Only moves if strong currents
Injuries---may scrape rough surfaces
Animal Predation---fish,crabs,turtles
Putrefaction----Body rises
Obese-----rise sooner
Putrefaction---signs of drowning absent,ID a
problem
Bathtub Deaths
• Adults---- Cardiac
Disease,Epilepsy,Intoxication (alcohol or
drugs) are major factors
• Homicide is rare---may be pulled by feet
• Young children---if left unattended,may
drown accidentally or rarely may be
drowned by siblings
Hot-tubs,Spas,Heated Whirlpools
• Young Children---hot water,if submerged
likely to develop anoxic brain injury rapidly
• Adults—Alcohol,Drugs
• Adults---Vasodilation,Stand Up,experience
Postural Hypotension
HYPOTHERMIA
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Below 35 degrees (Celsius)
Mild---- ----34 to 35
Moderate—30 to 34
Severe------below 30
HYPOTHERMIA
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INFANTS---Body Surface Area
Wet
Elderly
Alcohol and Drugs
Injury or Immobility
Mental Impairment
HYPOTHERMIA
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COMPLICATIONS
Pancreatitis
G-I mucosal ulcers
Pneumonia
Acute Tubular Necrosis
Myocardial Fibre Necrosis
HYPOTHERMIA
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PARADOXICAL UNDRESSING
Hallucinations
Feel Warm
“Hide and Die”---found under bed,in
wardrobe etc.
HYPERTHERMIA
• MILDER FORMS
• Heat Cramps---salt depletion---treat with
Rest in cool environment and salt
replacement
• Heat Exhaustion---loss of salt and water--treatment is similar
HYPERTHERMIA
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Defined as Core Temp above 40.5 deg C
HEAT STROKE
Life – Threatening
Direct thermal tissue injury
41deg C--- Mortality 75%
Factors---Alcohol,Drugs,Obesity
HYPERTHERMIA
• HEAT-STROKE
• Classic--- Elderly in prolonged heatwaves
• Exertional--- Young--- Extreme Exertion--eg seen in Athletes,Military
Recruits,Labourers
HYPERTHERMIA
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HEAT-STROKE----SIGNS & SYMPTOMS
Hyperthermia
Hot, Dry skin
CNS dysfunction--nausea,vomiting,cramps,dyspnoea
• Above 42.4 deg---Vasodilation and
Circulatory Collapse
HYPERTHERMIA
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HEAT-STROKE
In Survivors---Late Complications
Pneumonia
Acute Tubular Necrosis
Adrenal Haemorrhage
Hepatic Necrosis
Myocardial Necrosis
DIC
LIGHTNING
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Cloud to Ground Strikes usually
Most are NEGATIVE---5% are Positive
High-Voltage, Direct Current
Direct Strike--- Lightning Bolt
Indirect Strike---Side-Flash eg Tree—
current arcs to person standing nearby-----or Conduction through intermediary objects
eg telephone wires, waterpipes
LIGHTNING
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CLOTHING DEFECTS
Rips,tears,burns --- person may be NUDE
Singeing of body hair
Skin Burns--- jewellery,buckles,zips
Tympanic Membrane rupture
Lichtenberg Figure—fern-like red mark on skin--1 to 24 hours
• Death due to immediate Cardiopulmonary Arrest
• Secondary traumatic injuries-----eg falls
ELECTROCUTION
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OHM’S LAW---------- C = V/R
Current (Amperage ) most important
1mA---- tingle
5mA----muscle tremor
15mA---muscle contraction--hold-on effect
40mA---possible loss of conciousness
75-100mA– Ventricular Fibrillation
2Amps----Cardiac Arrest
ELECTROCUTION
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LOC may not be immediate
Low-Voltage eg domestic- --burns in 50%
Firm Contact--- crater with white edges
Loose Contact---yellow spark burn
Exit---may get a burn eg soles of feet
If exits over broad area,may be no burn
Burns may be hidden—eg mouth or lips
Prolonged Contact---severe burns
ELECTROCUTION
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HIGH VOLTAGE
Burns in virtually all cases
May be severe---tissue charring
Flash burns—multiple,small,pitted burns as
current dances over large area of body
• Heat may cause explosive injuries---loss of
limbs,rupture of viscera
ELECTROCUTION
• DOMESTIC SUPPLY
• IN IRELAND & UK
• Voltage sufficient to cause “hold – on”
effect
• Frequency of Current likely to cause cardiac
arrest
ELECTROCUTION
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SKIN OFFERS GREATEST RESISTANCE
Dry skin more resistant than wet skin
Thick skin more resistant than thin skin
Clothing--- rubber boots and gloves can
insulate
ELECTROCUTION
• CURRENT FLOW
• Different paths depending on entry and exit
sites
• If path involves heart or brain,a fatal
outcome is more likely
ELECTROCUTION
• CAUSE OF DEATH
• Low-voltage
• Must be direct contact between victim and
electrical circuit
• Ventricular Fibrillation is main cause
• If low current but long contact time,death
may be due to muscle paralysis and
asphyxia
ELECTROCUTION
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CAUSE OF DEATH
High-voltage
Respiratory Arrest or
Electrothermal Injuries
ASPHYXIA
• INADEQUATE OXYGENATION OF
TISSUES:
• SUFFOCATION
• STRANGULATION
• CHEMICAL ASPHYXIA
ASPHYXIA
• SUFFOCATION
• Failure of Oxygen to reach blood
• Environmental—closed chamber eg Silo (CO2),
Hold of Ship (N2)
• Smothering---mechanical obstruction of nose &
mouth---eg plastic bags,burial,gagging,
• In Infants--- pillows or pinching nose & clamping
mouth
ASPHYXIA
• CHOKING
• Blockage of Internal Airways
• Blockage of posterior pharynx and larynx
by food or foreign object
• Children------ Toys
• Adults ---- factors include
Alcohol,Senility,Mental Retardation
ASPHYXIA
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FOOD ASPIRATION
Rare as a genuine cause of death
Agonal aspiration common
Occurs in context of severe CNS depression
• ACUTE EPIGLOTTITIS
ASPHYXIA
• MECHANICAL ASPHYXIA
• Syn. Traumatic Asphyxia
• Pressure on chest & abdomen restricts
respiratory movement and inspiration
• Scenarios—car-jack,burial,cave-ins,crowd
crushes and stampedes
• May be no internal injuries
ASPHYXIA
• MECHANICAL ASPHYXIA
• OVERLAYING of INFANTS--indistinguishable from SIDS
• Positional Asphyxia—eg suspended upsidedown,crucifiction,wedged between
furniture,infants wedged in cots
• SIGNS---deep congestion of face &
neck,petechiae,scleral haemorrhages
ASPHYXIA
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CHEMICAL ASPHYXIA
Carbon monoxide—accidental,suicidal
Hydrogen cyanide---mostly suicidal
Hydrogen sulphide---accidental,affect
workers in sewer plants and cess-pools