Water intoxication, also known as water poisoning, hyperhydration, overhydration, or water toxemia is a potentially fatal disturbance in brain functions that results when the normal balance of electrolytes in the body is pushed outside safe limits by excessive water intake.
Under normal circumstances, accidentally consuming too much water is exceptionally rare. Nearly all deaths related to water intoxication in healthy individuals have resulted either from water drinking contests, in which individuals attempt to consume large amounts of water or from long bouts of exercise during which excessive amounts of fluid were consumed. In addition, water cure, a method of torture in which the victim is forced to consume excessive amounts of water, can cause water intoxication.
Water, just like any other substance, can be considered a poison when over-consumed in a specific period. Water intoxication occurs when water is consumed in a high quantity without adequate electrolyte intake.
At the onset of this condition, fluid outside the cells has an excessively low number of solutes, such as sodium and other electrolytes, in comparison to fluid inside the cells, causing the fluid to move into the cells to balance its concentration. This causes the cells to swell. In the brain, this swelling increases intracranial pressure (ICP), which leads to the first observable symptoms of water intoxication: headaches, personality changes, changes in behavior, confusion, irritability, and drowsiness.
These are sometimes followed by difficulty breathing during exertion, muscle weakness and pain, twitching, or cramping, nausea, vomiting, thirst, and a dulled ability to perceive and interpret sensory information. As the condition persists, papillary and vital signs may result including bradycardia and widened pulse pressure. The cells in the brain may swell to the point where blood flow is interrupted resulting in cerebral edema. Swollen brain cells may also apply pressure to the brain stem causing central nervous system dysfunction. Both cerebral edema and interference with the central nervous system are dangerous and could result in seizures, brain damage, coma or death. Source Credit: Wikipedia
Pathology findings are very limited in these deaths, and a proper and exhaustive scene investigation is vital. Along with scene information, a complete victim history of the past 24–36 hours needs to be completed.
Information gained through the investigation assists the pathologist in making a proper determination as to cause and manner of death. Since pathology findings will be limited, a misdiagnosis could occur without the complete investigative information. The investigator should determine the activities of the victim for the past 24-36 hours. Were they involved in intense sports such as a marathon? Were they dared or in a contest to see how much water they could consume? Alternatively, do they have a mental illness that would cause them to over consume water?
Other questions that should be asked are:
Was food consumed during this time?
Were sports drinks or other liquids with electrolytes consumed?
Was the victim sick with any flu-like symptoms that prevented them from desiring food?
It can be very easy for children under one-year-old to absorb too much water, especially if the child is under nine-months-old. Because of their small body mass, it is easy for them to take in a large amount of water relative to body mass and total body sodium stores.
In these cases, if water intoxication is suspected, a full history of the child’s fluid intake and statements from parents or caregivers is essential.