ENVIRONMENTAL DEATHS - PowerPoint PPT Presentation

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ENVIRONMENTAL DEATHS

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  1. ENVIRONMENTAL DEATHS ELEMENTS

  2. 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

  3. 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

  4. DROWNING • Hypoxia ---- Anoxia --- Brain Death • Conciousness lost within 3 minutes • Agonal Period -- vomiting (aspiration ), defaecation,urination,seminal emission

  5. Freshwater Drowning • Hypotonic • Large volumes of water pass through the alveoli and increase the blood volume • Haemolysis • Pulmonary Surfactant denatured

  6. Freshwater Drowning • Hypotonic • Large volumes of water pass through the alveoli and increase the blood volume • Haemolysis • Pulmonary Surfactant denatured

  7. Saltwater Drowning • Hypertonic • Plasma drawn into alveoli by osmosis • Decreased Blood Volume • Haemoconcentration • Raised Blood Electrolytes • Dilutes and washes away Pulmonary Surfactant

  8. Loss of Pulmonary Surfactant • Leads to Alveolar Collapse • Reduced Lung Compliance • Severe Ventilation/Perfusion Mismatch • Hypoxia

  9. Near-Drowning • First 24 hours after rescue • Sudden Cerebral Oedema is a major cause of death

  10. 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

  11. ICY WATER • Survival possible after prolonged submersion • “DIVING REFLEX”---Bradycardia,intense Vasoconstriction (except Brain and Heart)

  12. WARM WATER • Irreversible Cerebral Anoxia in 3-10 minutes

  13. 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

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 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

  19. HYPOTHERMIA • Below 35 degrees (Celsius) • Mild---- ----34 to 35 • Moderate—30 to 34 • Severe------below 30

  20. HYPOTHERMIA • INFANTS---Body Surface Area • Wet • Elderly • Alcohol and Drugs • Injury or Immobility • Mental Impairment

  21. HYPOTHERMIA • COMPLICATIONS • Pancreatitis • G-I mucosal ulcers • Pneumonia • Acute Tubular Necrosis • Myocardial Fibre Necrosis

  22. HYPOTHERMIA • PARADOXICAL UNDRESSING • Hallucinations • Feel Warm • “Hide and Die”---found under bed,in wardrobe etc.

  23. 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

  24. 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

  25. HYPERTHERMIA • HEAT-STROKE • Classic--- Elderly in prolonged heatwaves • Exertional--- Young--- Extreme Exertion---eg seen in Athletes,Military Recruits,Labourers

  26. HYPERTHERMIA • HEAT-STROKE----SIGNS & SYMPTOMS • Hyperthermia • Hot, Dry skin • CNS dysfunction---nausea,vomiting,cramps,dyspnoea • Above 42.4 deg---Vasodilation and Circulatory Collapse

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

  28. 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

  29. 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

  30. 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

  31. 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

  32. 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

  33. ELECTROCUTION • DOMESTIC SUPPLY • IN IRELAND & UK • Voltage sufficient to cause “hold – on” effect • Frequency of Current likely to cause cardiac arrest

  34. 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

  35. ELECTROCUTION • CURRENT FLOW • Different paths depending on entry and exit sites • If path involves heart or brain,a fatal outcome is more likely

  36. 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

  37. ELECTROCUTION • CAUSE OF DEATH • High-voltage • Respiratory Arrest or • Electrothermal Injuries

  38. ASPHYXIA • INADEQUATE OXYGENATION OF TISSUES: • SUFFOCATION • STRANGULATION • CHEMICAL ASPHYXIA

  39. 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

  40. 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

  41. ASPHYXIA • FOOD ASPIRATION • Rare as a genuine cause of death • Agonal aspiration common • Occurs in context of severe CNS depression • ACUTE EPIGLOTTITIS

  42. 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

  43. 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

  44. ASPHYXIA • CHEMICAL ASPHYXIA • Carbon monoxide—accidental,suicidal • Hydrogen cyanide---mostly suicidal • Hydrogen sulphide---accidental,affect workers in sewer plants and cess-pools