ENVIRONMENTAL DEATHS

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

• Hypertonic

• Plasma drawn into alveoli by osmosis

• Decreased Blood Volume

• Haemoconcentration

• Raised Blood Electrolytes

• Dilutes and washes away Pulmonary Surfactant

Loss of Pulmonary Surfactant

• 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

• 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

• 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

• 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

• 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

• Below 35 degrees (Celsius)

• Mild---- ----34 to 35

• Moderate—30 to 34

• Severe------below 30

HYPOTHERMIA

• INFANTS---Body Surface Area

• Wet

• Elderly

• Alcohol and Drugs

• Injury or Immobility

• Mental Impairment

HYPOTHERMIA

• COMPLICATIONS

• Pancreatitis

• G-I mucosal ulcers

• Pneumonia

• Acute Tubular Necrosis

• Myocardial Fibre Necrosis

HYPOTHERMIA

• 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

• 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

• HEAT-STROKE----SIGNS & SYMPTOMS

• Hyperthermia• Hot, Dry skin• CNS dysfunction---

nausea,vomiting,cramps,dyspnoea• Above 42.4 deg---Vasodilation and

Circulatory Collapse

HYPERTHERMIA

• HEAT-STROKE• In Survivors---Late Complications• Pneumonia• Acute Tubular Necrosis• Adrenal Haemorrhage• Hepatic Necrosis• Myocardial Necrosis• DIC

LIGHTNING

• 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

• 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

• 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

• 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

• 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

• 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

• 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

• 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 upside-

down,crucifiction,wedged between furniture,infants wedged in cots

• SIGNS---deep congestion of face & neck,petechiae,scleral haemorrhages

ASPHYXIA

• CHEMICAL ASPHYXIA

• Carbon monoxide—accidental,suicidal

• Hydrogen cyanide---mostly suicidal

• Hydrogen sulphide---accidental,affect workers in sewer plants and cess-pools