Fire Deaths. Dr Julie McAdam Consultant Forensic Pathologist Glasgow University

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1 Fire Deaths Dr Julie McAdam Consultant Forensic Pathologist Glasgow University

2 Forensic investigation multidisciplinary fire officers, police officers, scientists, photographers, pathologist, procurator fiscal occasionally pathologist is at the scene, but of more use afterwards

3 Why are we at the scene? do not routinely attend fire scenes requested by the procurator fiscal or investigating police officer usually only if there are suspicious circumstances only if body in situ!!!

4 What is the pathologist s role identification cause of death and certification documentation of injuries? alive during the fire pre-existing natural disease collection of samples (forensic and tox)

5 Heat injury Damage to tissues due to application of heat Narrow temperature range 20-44C Dependent on temperature and time applied eg. 3 seconds at 60C, 5hours at 44C (negligence cases) nb. average bath 36-42C Radiant heat (sunlight/lamps/heaters) eg. unconscious patients, unprotected by clothes

6 Dry heat burns usually high temperature, short duration superficial reddening +/- blistering, rim of erythema, sloughing at pm, can look like scald more severe - firm, yellow, leathery charring of soft tissue, muscle and bone, can have complete cremation of limbs

7 Severity of burns Various classifications, many clinical First degree - erythema and blistering, heals without scarring Second degree - destruction of full thickness of epidermis, exposing dermis, heals with scarring Third degree - destruction of subcutaneous tissue eg fat/muscle/bone

8 Severity of burns Partial thickness, superficial (1st degree) Partial thickness, deep (2nd degree) Full thickness (3rd degree) -discoloured layer of leathery discoloured tissue (eschar), may be assoc with severe tissue swelling, compromises blood flow, escharotomy to release pressure

9 Rule of Nines Estimation of area involved Prognostic significance Larger area more dangerous than deep localised 30-50% involvement incompatible with life Lower in elderly, higher in children

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11 What kind of cases do we see? Accidental Suicidal Criminal

12 Accidental fires children elderly alcoholics epileptics smokers RTA s

13 Suicidal fires not uncommon in some cultures religious martyrs need circumstances as may be homicide

14 Crime homicide concealment of homicide insurance fraud pyromania

15 Case one house fire body in situ probably suspicious

16 Case two body of an adult male in back of a van looks like he might have set himself on fire

17 Identification visual - may not be feasible fingerprints - may not be possible documents, jewellery etc dental records dna for comparison with relatives

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19 Causes of death inhalation of fumes burns and immediate complications other disease eg cardiovascular pre/post fire other injuries eg from escaping delayed complications

20 Fire Fumes cause of death in many fires, may have no surface burns thermal damage to airways and lungs soot in airways, useful marker of smoke inhalation, significant amount cannot pass the level of the vocal cords post mortem, microscopy absolute proof.

21 Fire Fumes carbon monoxide ongoing combustion, oxygen depleted cyanide (foam furnishings) and other toxic chemicals, stay on the floor

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23 Burns depends on severity and depth shock - dependent on extent fall in circulating blood volume due to fluid loss from burns and capillary wall leakage reflex cardiac arrest in severe pain

24 Delayed complications shock lung hypovolaemia infection, very susceptible, from skin/environment septicaemia bronchopneumonia pulmonary thromboembolism

25 ? Alive during the fire vital reaction around burns but often too severe to assess can get pm flare or NO vital reaction in known antemortem burns can get pm blisters, but no red base soot inhalation

26 ? Alive during fire CO level in blood 50-60% carboxyhaemoglobin can be low, flash fires, other gases negative does NOT mean death before the fire smokers have CO saturation of 5-6% in life

27 Post mortem findings partial/full thickness burns charring froth at the mouth/nose soot in airways burns in larynx and airways pulmonary oedema

28 Post mortem findings soot in stomach cherry pink blood and internal organs pre-mortem injuries natural disease delayed complications therapeutic intervention - escharotomies

29 Post mortem artefacts skin splits - contraction of damaged skin anywhere but especially extensor surfaces can be mistaken for antemortem injury, show no deep bleeding heat stiffening simulates rigor rigor mortis accelerated by heat, estimation of time of death

30 Post mortems artefacts flexion contractures - muscle becomes shortened by dehydration and denature of proteins, flexors bulkier than extensors typical pugilistic attitude heat fractures - skull and limbs, can mimic/obscure true injury

31 Post mortem artefacts heat haematoma - extradural, from venous sinuses or literally boiled out of bone bubbly and chocolate brown no associated fracture (unless heat fracture) can measure CO level in the haematoma if unsure

32 Spontaneous human combustion apparently inexplicable cases extensively burned body with minimal fire damage around usually near ignition point, often alcohol body fat can burn extremely slowly, clothing acts as a wick do not burst into flames

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