Scope of investigation:When a body is recovered from water, four critical questions require resolution:

• Was the victim alive or dead when he entered the water?

• Is the cause of death drowning? (and if not, what is the cause of death?).

• If drowning is determined to be the cause of death, is the manner of death accident,

suicide, or homicide?

• Are wounds present on the body, artifacts or evidence of primary injury which occurred

before drowning?

The circumstances preceding the death,

The circumstances of recovery of the body,

The autopsy findings. The approach should be to consider the circumstances

revealed by the investigation and to then determine if the autopsy findings are consistent with those circumstances.

To resolve the above questions, the following information must be correlated:

Drowning• Drowning may be defined as death due to

submersion in a liquid.• The mechanism of death in acute

drowning is irreversible cerebral anoxia. • The original concept of drowning death

was that they were asphyxial in nature with water occluding the airways.

Experiment in the late 1940s and early 1950s suggested that death was due to electrolytedisturbances and/or cardiac arrhytmias produced by large volumes of water entering the circulation through the lungs. Present thought, however, is that the most important physiological consequence of drowning is hypoxemia.

In drowning, the volume of water inhaled can range from relatively small to very large. In fresh water drowning especially, large volumes of water can pass through the alveolar-capillary interface and enter the circulation.

Even when large volumes of water are absorbed, there is no evidence that the increase in blood volume causes significant electrolyte irregularities or hemolysis, or that is beyond the capacity of the heart or kidneys to compensate for the fluid overload.

Dry DrowningSome individuals who drown are considered to be victims of “ dry drowning”. Here the fatal cerebral hypoxia is due to not to the conclusion of the airways by water but rather to a laryngeal spasm.Dry drowning is said to occur in 10 – 15% of all drownings.

Dry DrowningWhen a small amount of water enters the larynx or trachea, there is sudden laryngeal spasm mediated as a vagal reflex.

Thick mucous, foam, and froth may develop, producing an actual physical plug at this point. Thus, the water never enters into the lungs.

Laryngospasm cannot be demonstrated at autopsy.

When a person sinks beneath the surface of water, his initial reaction is breath holding. This continues until a breaking point is reached, at which time, the individual has to breath. The braking point is determined by a combination of high carbon dioxide levels and low oxygen concentrations. According to Pearn, the breaking point occurs at PCO2 levels below 55 mm Hg when there is associated hypoxia, and PAO2 levels below 100 mm Hg when the PCO2 is high.

Upon reaching the breaking point, the individual involuntarily inhales. At this time, water may reach the larynx and trachea, producing a laryngeal spasm with resultant dry drowning. In most instances, however, there is inhalation of large volumes of water. Some water is also swallowed and will be found in the stomach. During this interval of submersed breathing, the patient may also vomit and aspirate some gastric contents.

The involuntarily gasping for air under water will continue for several minutes, until it is irreversible and death occurs.

The point at which cerebral anoxia becomes irreversible is depend on both the age of the individual and the temperature of the water. With warm water, this time is somewhere between 3 and 10 min. submersion of children in extremely cold or icy water has resulted in successful resuscitation with intact neurological outcome for as long as 66 min following drowning.

Near DrowningThe term “near drowning” is occasionally encountered. This refers to a submersion victim who arrives at an emergency facility and survives for 24 h. this definition does not take into account whether ha has any neurological impairment.

Immersion artifacts occur in any corpse immersed in water, irrespective of whether death was from drowning or the person was dead on entering the water. Therefore, immersion artifacts do not contribute to proof of death by drowning. However, such artifacts are typically the most striking findings in a body recovered from water.

These immersion artifacts include: Goose-skin, or anserine cutis, which is roughening, or pimpling of the skin, Skin maceration, or washer-woman's skin, which is swelling and wrinkling of the skin, Adipocerous, which is the transformation of the fatty layer beneath the skin into a soap-like material - a process

requiring many weeks or months.

Drowned bodies commonly show an assortment of injuries caused by scaping the bottom, battering against solid object, carnivorous marine animals, and boat. Such injuries frequently arouse suspicion of foul play

A fine, white, froth or foam in the airways and exuding from the mouth and nostrils is characteristic of drowning. It is a vital phenomenon and indicates that the victim was alive at the time of submersion. However, similar foam is found in deaths from other causes, e.g. heart failure, drug overdose, and head injury.

It is disputed whether sand, silt, weed, and other foreign matter, found in the airways constitutes proof of immersion during life. The presence of large quantities of water and debris in the stomach strongly suggests immersion during life. Conversely, the absence of water in the stomach suggests either rapid death by drowning, or death prior to submersion.

Drowning is "suffocation due to immersion of the nostrils and mouth in a liquid". The mechanism of death is complex and is not simply an asphyxiation due to suffocation

There are no universally accepted diagnostic laboratory tests for drowning. The diatom test is used in some British laboratories and may provide corroborative evidence of death by drowning.

The lungs of drowning victim

The lungs are characteristically over-inflated and heavy with fluid. However, this is not invariable and, when present, macroscopically, it is not distinguishable from "fluid on the lungs" (pulmonary edema seen in heart failure, drug overdose and head injury).

In drowning, aqueous pulmonary emphysema and edema occur due to water aspiration and the lungs assumed a characteristic feature of the so called “drowning lung”.

Specifically, the lungs become markedly swollen and the borders become rounded; and the surface ; the surface appears pale and may exhibit hemorrhagic spots (the so called “paltoufsche flecke”) under the pleura, which are caused by rupture of the alveolar wall.

Aqueous pulmonary edema seen in drowning differs from ordinary pulmonary edema and is sometimes called dry edema.

The fluid with minute bits of foam is often expelled from the cut surface only when pressure is applied to a lung.

Several days after death, the aspirated water in the lungs shifts to the thoracic cavity through an infiltrative process.

If a large quantity ( more than 100 ml) of a hemolytic aqueous substance is found in the thoracic cavity of a corpse, there is a strong possibility that it had been drowned.

In case of an intracardiac hemorrhage in a person who drowned in fresh water, the blood contained in the left atrium is more diluted and shows a more acute sign of hemolysis than that of the right atrium.

If drowning occurs in sea water, the blood in the left atrium is frequently condensed. (the osmotic pressure of sea water is about 4 times that of the plasma; therefore the latter moves into the pulmonary alveoli, which explains the development of acute secondary edema shortly after drowning.)

These features are preserved even in those corpses that have been left in water for quite some time. Standard asphyxial features are also found.