Drowning is a form of asphyxial death where air entering into the lungs is prevented due to submersion of the mouth and nostrils into water or any other fluid medium. The process of submersion does not require the whole body to be underwater. Submersion of nose and mouth is sufficient. The causes of drowning can be the inability to utilize the buoyancy of the body, exhaustion, hypothermia, and getting trapped in whirlpool/tidal waves.
When a person falls in the water, he sinks to the depth of water which is proportional to the momentum acquired during the fall, weight, and the specific gravity of the body. At this point, death can happen due to head injury or coronary artery insufficiency or from sudden cardiac arrest due to vagal inhibition.
Our body has a natural buoyancy due to which the person rises again to the water surface. At this moment when the person struggles and cries for help, the person inhales and swallows water causing violent coughing. This results in froth formation because of the forceful expiratory effort. The formed froth will block the air entry but not the water entry.
More and more water gets inhaled because the body is forced to inhale due to the lack of oxygen and increase of CO2 in the body. The process of sinking and floating continues until complete exhaustion and insensibility sets in and finally the body sinks to the bottom. The time required for death to happen in freshwater drowning is 4-5 minutes.
The changes in blood and lung are also different in freshwater drowning and seawater drowning. Different types of drowning include typical (wet drowning) and atypical (dry drowning). Inhalation of fluid in the lungs causes reflex vasoconstriction, pulmonary hypertension, bronchoconstriction, increased airway resistance, denaturation of lung surfactant, lung compliance falls, decrease lung tissue for ventilation, abnormal ventilation/perfusion ratio, hypoxia, hypercapnia, respiratory acidosis, asphyxia.
Autopsy Findings in Downing Cases
- Clothes will be wet and sometimes aquatic animals can be seen trapped in garments.
- Skin will be wet, pale, and cold. The skin may be soiled with mud and weed and will show cutis anserina.
- Grass, mud, sand, etc. can be seen clinched in hands. Cadaveric spasm indicates that the person was alive when he was drowned.
- The appearance and disappearance of rigor mortis will be rapid.
- Subconjunctival hemorrhage can be seen and conjunctiva will be suffused and congested.
- The color of postmortem lividity may be bright pink due to the cold preservation of oxyhemoglobin and will be seen more prominently in the face, head, and neck region. But if it is moving water then the appearance of lividity is rare.
- Estimation of the approximate duration of immersion can be done by observing wrinkling, bleaching of the cuticle. Bleaching becomes evident after 12 hours of immersion, corrugation and soddening becomes pronounced within 24 hours. Cuticle begins to separate from the palm and sole by 48 hours.
- This whitening, soddening, wrinkling, and bleaching of the skin is known as a washerwoman’s hand.
- The froth produced due to the churning of air, mucus, and water is fine, whitish, leathery, and this froth oozes from the mouth and nostrils.
- Blood appears to be dark and fluid.
- If water is seen in the middle ear then it is a confirmed indication that it is antemortem drowning. Hemorrhage in the middle ear due to the pressure difference between the middle ear and surrounding water and mastoid air cells are also important signs of antemortem drowning.
- The swallowed water, mud, sand, silt, etc can be seen in the stomach and proximal intestine as well as in the respiratory passage.
- Microscopic examination can show the presence of diatoms.
- The weight of the lungs in drowning is around 600-700 gm but is normally around 370-540 gms.
- A condition called edema aquosum where the lungs will be filled with water but no froth will be present can be seen when there was no violent effort to breathe while in water. Instead, a condition called emphysema aquosum where the lungs will be heavy, doughy, spongy, and froth appearance indicates that the person was conscious while drowning and was struggling for life.
- Subpleural hemorrhages known as paltauf’s hemorrhages can be seen over the anterior surface and margins of the lungs.
- The lungs swell up and might show indentation marks of the ribs. When the lungs are cut, froth oozes out. In freshwater drowning, the lungs retain their shape.
Observing the autopsy and microscopical findings will help to differentiate and determine whether it was postmortem or antemortem drowning. Frothing is an indication that the person was conscious. Drowning can be suicidal, accidental, or homicidal.
Accidental drowning occurs in toddlers, and children who accidentally fall in the bathtub, well, pools, while fishing or during recreational activities like diving, boating, etc. findings also indicate the type of drowning.
The presence of diatoms is advantageous because it indicates that the person was alive while he was submerged, the place of drowning can be known and most importantly these can resist decomposition and so can be demonstrated even in highly decomposed bodies.