Presentation on theme: "Drowning or Immersion? Chris Lawrence. Drowning in Australia In western countries the incidence has been falling since the late 70’s from 7 to 2 per 100,000."— Presentation transcript:
Drowning in Australia In western countries the incidence has been falling since the late 70’s from 7 to 2 per 100,000 1.Australia: 369 in 2001 to 267 in 2005 2.NT x 3 national rate/head 3.Tas. x 2 national rate/head 4.Queensland slightly higher 5.Vic & ACT slightly lower 6.Ocean 664 Inland 493 Home 416 Farm 43 Data curtesy NCIS data base
Immersion or drowning? Can pathologist really tell whether someone has drowned or died of something else and ended up in the water? Immersion is exposure to water. Drowning is death due to inhalation of water. Some pathologists (W.A.) maintain that you cannot tell the difference and list all water deaths as immersion or drowning and immersion, but most pathologists still do use the term drowning.
A body found in water could have: 1.Died of natural disease before falling in 2.Died of natural disease in the water 3.Died of injuries then been thrown in water 4.Died of injuries while in water 5.Died of drowning 6.Died of hypothermia 7.Died of “dry drowning”, laryngeal spasm or sudden death on immersion
The scenarios 4. Suicide 18.4 % of drowning a)Mental illness b)Issues relating to medical assessment of suicide risk c)Jump from Tasman bridge (46m) a)Death from impact b)Unconscious or injured then drown c)Survive
The scenarios 5. Death in the Bathtub a)Babies and young children b)Homicides in babies & young women c)Drug OD accidental & suicide d)Seizures & disabled- issue of supervision e)Electrocution f)Natural disease g)“fall” in the bath tub
Changes of Drowning 1.Plume of pulmonary oedema (early) 2.Pulmonary oedema in the upper airway 3.Overexpanded lung
Overexpanded Lungs due to drowning Lungs expanded to cover mediastinum & rib marking “emphysema aquosum” I suspect this is more obvious in salt water drowning than fresh water drowning where the water is rapidly absorbed in the body. However, no significance difference in lung weight in salt and fresh water in studies. Locali 2006
Changes from being in water (immersion) 1.Maceration of skin 2.“Washer woman’s hands” 3.Detachment of skin “glove and stocking” 4.Water in the stomach and sinuses. 5.Sand/ weed in lungs & stomach 6.Post mortem injury due to fish 7.Leaching of blood from wounds makes it very difficult to distinguish peri-mortem injuries from post mortem injuries
How common are signs of drowning? Lunetta et al 2002, Retrospective study of 1590 bodies found in water 1.Plume of pulmonary oedema 17.3 % 2.Pulmonary oedema in airways46.5% 3.Overexpanded lung 42.1% 4.All three 18.3% 5.No diagnosis determined on basis of circumstances & PM changes 41.5%
Washerwoman hands This is a sign of immersion not drowning
Water in the stomach Not usually this obvious! Water may be found in the stomach in some dumped bodies, therefore probably a sign of immersion not drowning
Immersion Haemorrhage in the middle ear. This is probably cause by barotrauma of descent Recent “virtual autopsy” CT scan study 1.Fluid & sediment in sinuses & ears, 2.Fluid in the trachea and 3.Ground glass opacities in the lung. Levy et al Radiology 2007 Jun;243(3):862-8. If water in the stomach can occur in immersion can water in the sinus also occur in immersion?
Has this injury occurred before or after death? Hard to tell - 1.Skin loss in water (Maceration) 2.Bites from marine animals 3.Leaching of blood from peri-mortem injuries
Shark attack or Drowning Bleeding suggests peri-mortem injury Post –mortem scavenging of bodies also common
Tests for drowning - Diatoms Unicellular silicate organisms present in water Test for diatoms in blood, bone marrow or kidney Dissolve tissue in concentrated acid Compare to water samples from the scene
Problems with diatoms 1.Not widely available 2.Uses concentrated acid 3.Contamination by exogenous diatoms 4.False negatives due to loss of diatoms 5.Enzymatic maceration may be better 6.Indicative aid not proof of drowning 7.Works best when abundant diatoms 8.Some studies very critical of diatoms
Other tests for drowning 1.Gettler test a)Due to salt water in the lungs, blood from the left ventricle will have a higher Chloride level than the right ventricle. b)Due to fresh water in the lungs, blood from the left ventricle will have a lower Chloride level than the right ventricle. c)Nice theory but does not work in practise. 2.Magnesium, strontium, chlorophyll? 3.Red staining of the intima of the aorta due to haemolysis in fresh water drowning? Artefact or real ?
Rapid death on immersion 1.“Dry Drowning” said to be 10-15 % of cases 2.Laryngeal spasm on contact with cold water, not inhalation of water 3.Bradycardia related to “Diving Reflex” 4.Said to be more common in children, cold water & alcohol 5.Some may represent cardiac arrhythmia due to long QT syndrome Type I (KCNQ1) I have not seen a convincing case of dry drowning. Carl Edmonds (diving medicine expert) is doubtful about the existence of dry drowning. Fresh water absorbed into blood
Hypothermia Water temp( 0 C) Exhaustion (h)Survival (h) 21 - 27 0 C 3 – 12 h3 – ∞ h 16 – 21 0 C 2 – 7 h2 – 40 h 10 – 16 0 C 1 – 2 h1 – 6 h 4 – 10 0 C ½ – 1 h1 – 3 h 0 0 C < ¼ h< ¼ – ¾ h
Drowning may be due to 1.Inadequate water skills (especially children) 2.Dangerous water conditions, currents and rips 3.Fatigue/ panic 4.Decreased level of consciousness i.Intoxication ii.Epilepsy iii.Trauma 5.Natural disease i.Acute myocardial infarct ii.Asthma iii.Diabetes 6.Entrapment 7.Physical disability 8.Homicide
Drowning At autopsy there are no pathognomic findings …of drowning. The diagnosis is based on the circumstances of the death, plus a variety of non- specific anatomical findings. Chemical tests…are … unreliable. A diagnosis of drowning cannot be made without a complete autopsy, esp. complete toxicology, because this is a diagnosis of exclusion. If an individual is found in water and all other causes of death have been excluded, he is presumed to have drowned. DiMaio 1993
Homicidal drowning Mr George Joseph Smith drowned 3 of his wives in the bath by sudden pulling of the feet so that their heads slid under water. Recent big insurance policy. Beware of the dead young woman in the bath with bruises on their calves Homicidal drowning of babies undetectable.
Cause of death in Scuba divers MULTIFACTORIAL 1.Medical factors- pathology, panic,fatigue, lack of fitness 2.Diving technique- out of air, separation 3.Equipment-faults, misuse and loss 4.Environmental factors - current, depth, visibility 5.Requires significant understanding of the physics and practise of scuba diving
Causes of gas at autopsy 1.Pulmonary barotrauma/Cerebral arterial gas embolism 2.Decomposition. 3.Resuscitation. 4.Post-mortem decompression or “off-gassing” Underwater nitrogen under pressure dissolves in tissues. After return to the surface nitrogen bubbles form in blood and tissues.
Pre-autopsy CT scan of body 1.NEEDS TO BE DONE WITHIN 8 HOURS OF DEATH 2.Dive to 18m for 45 minutes will cause significant post- mortem off gassing after 8 hours due to dissolved nitrogen 3.Imaging unless done within a few hours of death may be a waste of time