Forensic Medical Opinion of Drowning

Why Drowning Is Difficult to Certify

• Homicide, suicide, or accident by actual drowning
• Natural disease (e.g., cardiac arrest) that caused collapse into water
• Intoxication (alcohol, drugs) before submersion
• Trauma before or after entering the water

Essential Components for the Opinion

1. Scene Investigation

• Circumstances under which the body was found
• Depth and type of water (fresh vs. salt, river, pool, bath)
• Whether immersion was witnessed
• Presence of grip marks, ligature marks, or signs of struggle nearby
• Toxicology screening (alcohol, drugs)

2. Autopsy - External Findings

3. Autopsy - Internal Findings

• Voluminous, overinflated lungs that bulge out of the chest and cover the pericardium - called "ballooning" - due to fluid and air in the bronchi
• Rib impressions (grooves) on the lateral surface of the lungs - an important sign of drowning
• Emphysema aquosum - watery, frothy fluid throughout lung tissue, present in ~80% of cases; considered presumptive evidence of drowning
• If the victim was unconscious at submersion: oedema aquosum (mere flooding without froth formation)
• Cross-section yields watery, frothy, sometimes blood-stained fluid

• Water found in stomach in ~70% of cases
• If the water chemically matches the drowning medium (e.g., muddy/foul water not voluntarily swallowed), it is strong confirmatory evidence
• Sehrt's sign: micro-ruptures of gastric mucosa from fluid distension
• Wydler's sign: gastric contents separate into 3 layers when left to stand (solids at bottom, liquid in middle, foam on top)
• Small intestine contains water in ~20% of cases (requires antemortem peristalsis, so it is probable evidence)

• Ueno's sign: water forced into the middle ear through the Eustachian tube - suggestive of antemortem drowning
• Hemorrhages in the middle ear (~50% of cases)
• Hemorrhage in temporal bone / mastoid air cells
• Congested, swollen brain with flattened gyri
• Dark, fluid blood in the right heart (diluted by inhaled fluid)
• Red staining of the aortic intima

4. Laboratory Investigations

• Diatoms are microscopic algae with silica skeletons found in natural water
• In drowning, diatoms enter through the damaged pulmonary capillaries and reach deep organs - bone marrow, brain, liver, kidneys
• Finding similar diatoms in these organs as in the drowning medium is strong evidence of antemortem drowning
• A dead body thrown into water will NOT have diatoms in deep organs
• Limitations: negative in clean/chlorinated water; can be false positive from diatoms consumed in drinking water
• Acid digestion method is used: tissue is treated with strong nitric/sulfuric acid, centrifuged, washed, and examined under polarized microscopy

• Normally, right and left heart blood has equal chloride (~600 mg/100 ml)
• In fresh water drowning: blood diluted in left heart → chloride in left heart is up to 50% LOWER than right
• In sea water drowning: hemoconcentration → chloride in left heart up to 30-40% HIGHER than right
• A 25% difference is considered significant, but the test is of doubtful value

• In drowning, plasma from the left heart has lower specific gravity than the right (due to dilution from aspirated fluid)

Manner of Death Determination

Homicidal drowning is possible without marks of violence if the victim is intoxicated or sedated - the head need only be submerged 5-10 minutes. The famous "Brides of the Bath" case (George Joseph Smith, hanged 1915) demonstrated that pulling a victim's legs upward while supine causes immediate unconsciousness from sudden submersion of the head, leaving no marks.

Special Scenarios

• Dry drowning (~10-15%): No water enters the lungs; death from laryngeal spasm at the moment of immersion
• Secondary/delayed drowning: Death after initial rescue from electrolyte disturbances (metabolic acidosis, hyperkalemia), adult respiratory distress syndrome; lungs are rigid, stiff, heavy
• Death in bathtub: Must exclude cardiac/cerebrovascular disease, epilepsy, CO poisoning, electrocution, homicide
• Death of newborn infants in toilet/bucket: Requires microscopy of lung parenchyma and comparison with fluid sample
• Hydrostatic lung: A dead body placed in water >2 meters deep for >20 hours can develop lung changes mimicking drowning - diatom test and frothy fluid combination is then needed to differentiate

Final Opinion Framework

1. Autopsy shows characteristic features (wet lungs, froth, stomach water)
2. All other natural causes of death are excluded
3. Laboratory tests (diatoms, chloride, toxicology) support drowning
4. Scene findings and history are consistent
5. The finding of diatoms matching the drowning medium in deep organs provides the strongest confirmatory evidence

How to Answer "What is the Opinion of Drowning?" in Viva

Step 1 - Define it first (always start with a definition)

"Drowning is a form of asphyxia due to aspiration of fluid into the air passages, caused by submersion in water or other fluid. It is a non-violent form of mechanical asphyxia."

Step 2 - State that it is a Diagnosis of Exclusion

"The opinion of drowning is a diagnosis of exclusion. Before certifying death due to drowning, all other possible causes of death must be ruled out, including natural disease, trauma, poisoning, and intoxication."

Step 3 - Give the Medico-legal Opinion (the actual "opinion" part)

"To give an opinion of drowning, I would consider the following:"

"The body was recovered from water. The scene, circumstances, and type of water - fresh or salt - are noted."

"Externally, I would look for:

• Fine, persistent froth at the mouth and nostrils
• Washerwoman's skin - maceration of palms and soles
• Cutis anserina - gooseflesh appearance
• Cadaveric lividity on the face and anterior chest due to prone floating position
• Abrasions on knuckles, knees, forehead from contact with the bottom"

"Internally:

• Lungs are voluminous and overinflated - called ballooning - with rib impressions on their surface
• Emphysema aquosum is present in about 80% of cases - frothy, watery fluid throughout lung tissue - this is presumptive evidence of drowning
• Stomach contains water in 70% of cases
• Sehrt's sign - micro-ruptures of gastric mucosa
• Wydler's sign - gastric contents separate into 3 layers on standing
• Ueno's sign - water in the middle ear - suggestive of antemortem drowning
• Brain is congested and swollen"

"For confirmatory evidence, I would perform:

• Diatom test - finding diatoms matching the drowning medium in deep organs like bone marrow, brain, and liver is the strongest confirmatory evidence of antemortem drowning
• Gettler test - a 25% difference in chloride levels between right and left chambers of the heart supports drowning
• Toxicology - to exclude alcohol or drug intoxication as contributing or independent cause"

Step 4 - State the Manner of Death

"After establishing cause of death as drowning, I would determine the manner:

• Accidental - most common
• Suicidal - weighted pockets, prior intent, note
• Homicidal - grip marks on limbs, signs of violence, drugs used to incapacitate - drowning in shallow water in an adult is presumptive of homicide
• Undetermined - if circumstances are insufficient"

Step 5 - Closing statement (impresses examiners)

"The opinion of drowning requires convergence of multiple findings - scene, external, internal, and laboratory. No single test alone is sufficient to certify death due to drowning."

Quick Memory Aid for Viva

Examiner tip: If asked "What is the most important confirmatory test?" - always say diatom test, and mention that finding diatoms matching the drowning medium in bone marrow is the gold standard because it proves the person was alive during submersion.