Drowning

This article contains graphic images from real cases which may be disturbing to some viewers.
Viewer discretion is advised. 

Drowning is defined as death caused by submersion in a liquid. It can occur in an ocean or, in the case of alcoholic stupor, epileptics, or infants, in water as shallow as 6 in. The mechanism of death in acute drowning is irreversible cerebral anoxia. The most important physiological consequence of drowning is asphyxia. In drowning, the volume of water inhaled can range from relatively small to very large. In freshwater 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 it is beyond the capacity of the heart or kidneys to compensate for the fluid overload.

Some individuals who drown are considered to be victims of “dry drowning.” The lungs do not have the heavy, boggy and edematous appearance typical of drowning lungs. It is  to be caused by laryngeal spasm. Dry drowning is said to occur in 10–15% of all drownings. What is theorized to occur is that when a small amount of water enters the larynx or trachea, there is a sudden laryngeal spasm mediated as a vagal reflex. Thick mucous, foam, and froth may develop, producing an actual physical plug at this point. Thus, water never enters the lungs. The “physical plug” occurs in the larynx and the “laryngospasm” cannot be demonstrated at autopsy. Dry drowning is interesting, it is a hypothesis, not proven. It is probable that dry drowning is just one end of a spectrum of changes seen in the lung produced by occlusion of the airways by water, with the other end the heavy, boggy lung containing a massive amount of edema fluid. When people sink beneath the surface of water, their initial reaction is to hold their breath. This continues until a breaking point is reached.  According to Pearn, the breaking point occurs at PC02 levels below 55 mm Hg when there is associated hypoxia, and at PA02 levels below 100 mm Hg when the PC02 is high. Reaching the breaking point, the individual involuntarily inhales, taking in 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 involuntary gasping for air under water will continue for several minutes, until respiration ceases and death occurs.

   

The point at which cerebral anoxia becomes irreversible is dependent 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. No matter what the time interval involved, consciousness is usually lost within 3 min of submersion.

The sequence of events is:

1. Breath holding
2. Involuntary inspiration and gasping for air at the breaking point
3. Loss of consciousness
4. Heath

Hyperventilation can cause significant decrease in the CO2 levels. Thus, cerebral hypoxia due to low blood P02, with development of unconsciousness, might occur before the breaking point is reached. In this case, the sequence would be:

1. Voluntary holding of breath
2. Unconsciousness
3. Aspiration of water

The type of water that is inhaled, fresh versus salt, probably has very little influence on whether the individual will survive.

The 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 these individuals subsequently survive or, if they survive, whether they have any neurological impairment. In the near drowning there are electrolyte changes, the electrolyte. As mentioned, survival following prolonged underwater submersion in ice cold water may be for as long as 66 min in the case of children and infants. Immature brains are more resistant to anoxia and that the “diving reflex” is still present in children. The diving reflex refers to vasoconstriction in the vascular beds (except for the heart and brain), shunting of blood to the brain and heart and bradycardia, all triggered by immersion of the face in cold water. Bradycardia does occur, but there has been no proof of the vasoconstriction in the vascular beds with shunting of blood to the heart and brain. Many people feel that these children survive because of the rapid development of hypothermia. It was proven that in warm water, a submersion time of 3–10 min is believed to represent the maximum time prior to irreversible neurological injury, in ice water, submersion times as long as 66 min have been reported with neurological recovery. A diagnosis of drowning cannot be made without a complete autopsy and a complete toxicological screen, this is a diagnosis of exclusion. If individuals are found in water and all other causes of death have been excluded, they are presumed to have drowned. It must be remembered, however, that people have fatal heart attacks and fall into water, and that victims of a fatal drug overdose are occasionally “dumped” into a body of water.

When a person drowns, the body sinks, assuming a position of head down, buttocks up, and extremities dangling downward. Unless there are strong currents, the body will not move very far from its initial position. In shallow water, the extremities or face may bump or drag against the bottom of the body of water, often causing postmortem injuries to the face, back of the hands, knees, and toes. The crown of the head and the buttocks can be seen at water level. In deeper water, the body stays below the surface until decomposition begins and gas forms; the body then gradually rises to the surface. In very cold water, the body might stay submerged for months before decomposition creates enough gas to bring it to the surface. Depending on how long a body has been in the water, there might be evidence of animal activity, for example, fish, turtles, crabs, or shrimp. The bodies that appear relatively intact, when opened up, reveal complete absence of the thoracic and abdominal viscera. Examination will reveal a defect(s) in the trunk that communicates with the chest or abdominal cavity, through which water denizens have eaten their way inside - consumed the internal viscera. The presence of vegetation and stones that can be found at the bottom of the body of water found clutched in the hands indicate that the cause of death was, in fact, drowning, the deceased was alive when entering the water.

An important is a test involving the identification of diatoms in the tissue of drowning victims. If diatoms are present in a body, there are three possible ways they could have gotten there. First is by inhalation of airborne diatoms, second is by ingestion of material containing diatoms, and third is by aspiration of water containing diatoms, with subsequent circulation of these throughout the body. We can find diatoms in lungs, liver, kidney, and bone marrow. Drownings in bathtubs which are relatively uncommon, usually involving young children left unattended by a parent. Some undoubtedly are homicides.

Acknowledgements:

The Police Department; 

https://www.politie.nl/mijnbuurt/politiebureaus/05/burgwallen.html and a Chief Inspector – Mr. Erik Akerboom                                 ©

 Bibliography:

1. Criminal Investigations – Crime Scene Investigation.2000
2. Forensic Science.2006
3. Techniques of Crime Scene Investigation.2012
4. Forensics Pathology.2001
5. Pathology.2005  
6. Forensic DNA Technology (Lewis Publishers,New York, 1991).
7. The Examination and Typing of Bloodstains in the Crime Laboratory (U.S. Department of Justice, Washington, D.C., 1971).
8. „A Short History of the Polymerase Chain Reaction". PCR Protocols. Methods in Molecular Biology.
9. Molecular Cloning: A Laboratory Manual (3rd ed.). Cold Spring Harbor,N.Y.: Cold Spring Harbor Laboratory Press.2001
10. "Antibodies as Thermolabile Switches: High Temperature Triggering for the Polymerase Chain Reaction". Bio/Technology.1994
11. Forensic Science Handbook, vol. III (Regents/Prentice Hall, Englewood Cliffs, NJ, 1993).
12. "Thermostable DNA Polymerases for a Wide Spectrum of Applications: Comparison of a Robust Hybrid TopoTaq to other enzymes". In Kieleczawa J. DNA Sequencing II: Optimizing Preparation and Cleanup. Jones and Bartlett. 2006
13. Modell JH and Davis JH, Electrolyte changes in human drowning victims. Anesthesiology 1969
14. Bolte RG, et al., The use of extracorporeal rewarming in a child submerged for 66 minutes. JAMA 1988
15. Ornato JP, The resuscitation of near-drowning victims. JAMA 1986
16. Conn AW and Barker CA: Fresh water drowning and near-drowning — An update.1984;
17. Reh H, On the early postmortem course of “washerwoman’s skin at the fingertips.” Z Rechtsmed 1984;
18. Gonzales TA, Vance M, Helpern M, Legal Medicine and Toxicology. New York, Appleton-Century Co, 1937.
19. Peabody AJ, Diatoms and drowning – A review, Med Sci Law 1980
20. Foged N, Diatoms and drowning — Once more.Forens Sci Int 1983
21. "Microscale chaotic advection enables robust convective DNA replication.". Analytical Chemistry. 2013
22. Sourcebook in Forensic Serology, Immunology, and Biochemistry (U.S. Department of Justice, National Institute of Justice, Washington, D.C.,1983).
23. C. A. Villee et al., Biology (Saunders College Publishing, Philadelphia, 2nd ed.,1989).
24. Molecular Biology of the Gene (Benjamin/Cummings Publishing Company, Menlo Park, CA, 4th ed., 1987).
25. Molecular Evolutionary Genetics (Plenum Press, New York,1985).
26. Human Physiology. An Integrate. 2016