Drowning or Immersion?

1
Drowning or Immersion?

• Chris Lawrence

2
Drowning in Australia

• In western countries the incidence has been
  falling since the late 70s from 7 to 2 per
  100,000
• Australia 369 in 2001 to 267 in 2005
• NT x 3 national rate/head
• Tas. x 2 national rate/head
• Queensland slightly higher
• Vic ACT slightly lower
• Ocean 664 Inland 493 Home 416 Farm 43
• Data curtesy NCIS data base

3
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.

4
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

5
The scenarios

• Swimming pools farm dams
• Young children
• No fencing
• No supervision
• Surf deaths
• Teenagers
• Neck injuries
• Alcohol and drugs
• Sailors fishermen
• All ages
• Alcohol
• Adequate floatation devices
• Hypothermia

6
The scenarios

• 4. Suicide 18.4 of drowning
• Mental illness
• Issues relating to medical assessment of suicide
  risk
• Jump from Tasman bridge (46m)
• Death from impact
• Unconscious or injured then drown
• Survive

7
The scenarios

• 5. Death in the Bathtub
• Babies and young children
• Homicides in babies young women
• Drug OD accidental suicide
• Seizures disabled- issue of supervision
• Electrocution
• Natural disease
• fall in the bath tub

8
Changes of Drowning

• Plume of pulmonary oedema (early)
• Pulmonary oedema in the upper airway
• Overexpanded lung

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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
10
Changes from being in water (immersion)

1. Maceration of skin
2. Washer womans 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

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How common are signs of drowning?

• Lunetta et al 2002, Retrospective study of 1590
  bodies found in water
• Plume of pulmonary oedema 17.3
• Pulmonary oedema in airways 46.5
• Overexpanded lung 42.1
• All three 18.3
• No diagnosis determined on basis of circumstances
  PM changes 41.5

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Washerwoman hands
This is a sign of immersion not drowning
13
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
14
Immersion

• Haemorrhage in the middle ear.
• This is probably cause by barotrauma of descent
• Recent virtual autopsy CT scan study
• Fluid sediment in sinuses ears,
• Fluid in the trachea and
• Ground glass opacities in the lung.
• Levy et al Radiology 2007 Jun243(3)862-8.
• If water in the stomach can occur in immersion
  can water in the sinus also occur in immersion?

15
Has this injury occurred before or after death?

• Hard to tell -
• Skin loss in water (Maceration)
• Bites from marine animals
• Leaching of blood from peri-mortem injuries

16
Shark attack or Drowning
Bleeding suggests peri-mortem injury
Post mortem scavenging of bodies also common
17
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

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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

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Other tests for drowning

• Gettler test
• Due to salt water in the lungs, blood from the
  left ventricle will have a higher Chloride level
  than the right ventricle.
• Due to fresh water in the lungs, blood from the
  left ventricle will have a lower Chloride level
  than the right ventricle.
• Nice theory but does not work in practise.
• Magnesium, strontium, chlorophyll?
• Red staining of the intima of the aorta due to
  haemolysis in fresh water drowning? Artefact or
  real ?

20
Rapid death on immersion

• Dry Drowning said to be 10-15 of cases
• Laryngeal spasm on contact with cold water, not
  inhalation of water
• Bradycardia related to Diving Reflex
• Said to be more common in children, cold water
  alcohol
• 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

21
Hypothermia
Water temp(0C) Exhaustion (h) Survival (h)
21 - 27 0C 3 12 h 3 8 h
16 21 0C 2 7 h 2 40 h
10 16 0C 1 2 h 1 6 h
4 10 0C ½ 1 h 1 3 h
0 0C lt ¼ h lt ¼ ¾ h
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Drowning may be due to

• Inadequate water skills (especially children)
• Dangerous water conditions, currents and rips
• Fatigue/ panic
• Decreased level of consciousness
• Intoxication
• Epilepsy
• Trauma
• Natural disease
• Acute myocardial infarct
• Asthma
• Diabetes
• Entrapment
• Physical disability
• Homicide

23
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
  testsare 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

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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.

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Cause of death in Scuba divers

• MULTIFACTORIAL
• Medical factors- pathology, panic,fatigue, lack
  of fitness
• Diving technique- out of air, separation
• Equipment-faults, misuse and loss
• Environmental factors - current, depth,
  visibility
• Requires significant understanding of the physics
  and practise of scuba diving

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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.

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Pre-autopsy CT scan of body

• NEEDS TO BE DONE WITHIN 8 HOURS OF DEATH
• Dive to 18m for 45 minutes will cause significant
  post-mortem off gassing after 8 hours due to
  dissolved nitrogen
• Imaging unless done within a few hours of death
  may be a waste of time