Water intoxication

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Water intoxication
Classification and external resources
 
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Water intoxication
Classification and external resources

Water intoxication, also known as water poisoning, is a potentially fatal disturbance in brain functions that results when the normal balance of electrolytes in the body is pushed outside of safe limits (e.g., hyponatremia) by overhydration, i.e., over-consumption of water.

Under normal circumstances, accidentally consuming too much water is exceptionally rare. Nearly all deaths related to water intoxication in normal individuals have resulted either from water drinking contests in which individuals attempt to consume large amounts of water, or long bouts of intensive exercise during which electrolytes are not properly replenished, yet huge amounts of fluid are still consumed.[1]

Water, just like any other substance, can be considered a poison when over-consumed in a specific period of time. Water intoxication mostly occurs when water is being consumed at a high quantity without giving the body its proper nutrients it needs to be healthy.[2]

Excess of body water may also be a result of a medical condition or improper treatment; see "hyponatremia" for some examples. Water is considered the least toxic chemical compound, with a LD50 of 90 g/kg or more in rats.[3]

Contents

Physiology

At the onset of this condition, fluid outside the cells has an excessively low amount of solutes (such as sodium (hyponatremia) and other electrolytes) in comparison to that inside the cells causing the fluid to shift through (via osmosis) into the cells to balance its concentration. This causes the cells to swell. In the brain, this swelling increases intracranial pressure (ICP). It is this increase in pressure which leads to the first observable symptoms of water intoxication: headache, personality changes, changes in behavior, confusion, irritability, and drowsiness. These are sometimes followed by difficulty breathing during exertion, muscle weakness, 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.[4]

Risk factors

Low body mass (infants)

It can be very easy for children under 1 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 to take in a large amount of water relative to body mass and total body sodium stores.[5]

Endurance sports

Marathon runners are susceptible to water intoxication if they drink too much while running. This is caused when sodium levels drop below 135 mmol/L when athletes consume large amounts of fluid. This has been noted to be the result of the encouragement of excessive fluid replacement by various guidelines. This has largely been identified in marathon runners as a dilutional hyponatremia.[6] Medical personnel at marathon events are trained to suspect water intoxication immediately when runners collapse or show signs of confusion.

Overexertion and heat stress

Any activity or situation that promotes heavy sweating can lead to water intoxication when water is consumed to replace lost fluids. Persons working in extreme heat and/or humidity for long periods must take care to drink and eat in ways that help to maintain electrolyte balance. People using drugs such as MDMA (often referred to colloquially as "Ecstasy") may overexert themselves, perspire heavily, and then drink large amounts of water to rehydrate, leading to electrolyte imbalance and water intoxication – this is compounded by MDMA use increasing the levels of antidiuretic hormone (ADH), decreasing the amount of water lost through urination.[7] Even people who are resting quietly in extreme heat or humidity may run the risk of water intoxication if they drink large amounts of water over short periods for rehydration.

Psychiatric conditions

Psychogenic polydipsia is the psychiatric condition in which patients feel compelled to drink large quantities of water, thus putting them at risk of water intoxication. This condition can be especially dangerous if the patient also exhibits other psychiatric indications (as is often the case), as the care-takers might misinterpret the hyponatremic symptoms.

Iatrogenic

When an unconscious person is being fed intravenously (for example, total parenteral nutrition) or via a nasogastric tube the fluids given must be carefully balanced in composition to match fluids and electrolytes lost. These fluids are typically hypertonic, and so water is often co-administered. If the electrolytes are not monitored (even in an ambulatory patient) either hypernatremia or hyponatremia may result.[8]

Some neurological/psychiatric medications (Oxcarbazepine, among others) have been found to cause hyponatremia in some patients.[9] Patients with diabetes insipidus are particularly vulnerable due to rapid fluid processing.[10]

Prevention

Water intoxication can be prevented if a person's intake of water does not grossly exceed his or her losses.[11] Healthy kidneys are able to excrete approximately 1 litre of fluid water (0.26 gallons) per hour.[11] However, stress (from prolonged physical exertion), as well as disease states, can greatly reduce this amount.[11]

Treatment

Mild intoxication may remain asymptomatic and require only fluid restriction. In more severe cases, treatment consists of:

Notable cases

See also

References

  1. ^ A study refers to a renal excretion capacity of 3 ml/hr
  2. ^ http://learn.caim.yale.edu/chemsafe/references/dose.html
  3. ^ [1] - see to Section 11: Toxicological Information for the LD50 verification
  4. ^ David Moreau, ed. Fluids and electrolytes made incredibly easy! 4th edition. Lippincott Williams & Wilkins. 
  5. ^ Water Intoxication in Infants
  6. ^ Hyponatremia among Runners in the Boston Marathon - The New England Journal of Medicine
  7. ^ http://books.google.com.au/books?id=qYYOtQU37jcC&printsec=frontcover#v=onepage&q=leah%20betts&f=false
  8. ^ Treating Hypernatremic Dehydration
  9. ^ Oxcarbazepine
  10. ^ What Is Diabetes Insipidus?
  11. ^ a b c Strange but True: Drinking Too Much Water Can Kill
  12. ^ "Hyponatremia ("Water Intoxication")". The DEA.org. http://thedea.org/hyponatremia.html. Retrieved 2007-05-10. 
  13. ^ Grier, Peter (January 2000). "Airman's Death Brings Training Changes". Aerospace World (Air Force Magazine Online). Archived from the original on 2007-03-16. http://web.archive.org/web/20070316235525/http://www.afa.org/magazine/Jan2000/0100world.asp#anchornine. Retrieved 2007-01-20. 
  14. ^ "Split verdict surprises and stuns the Killpacks". Deseret News. October 13, 2005. http://deseretnews.com/dn/view/0,1249,630152910,00.html. Retrieved 2008-08-24. 
  15. ^ Local10.com/WPLG report of water intoxication murder arrest
  16. ^ Sun-Sentinel article: Nancy Gayoso declared competent to stand trial
  17. ^ Local10.com/WPLG report: "Judge: Baby Sitter in Water Intoxication Death Still Not Competent"
  18. ^ "Wrongful-death judgment handed down for 2003 PSU hazing". The Press Republican(Google cached version). December 5, 2007. http://webcache.googleusercontent.com/search?q=cache:http://pressrepublican.com/homepage/local_story_339013010.html. Retrieved 2010-04-27. 
  19. ^ Lore, Mark (2005-02-10). "Another death in the family". Chico news & review. http://www.newsreview.com/chico/Content?oid=oid%3A33779. Retrieved 2007-05-10. 
  20. ^ "Woman dies after water-drinking contest". MSNBC. January 13, 2007. http://www.msnbc.msn.com/id/16614865/. Retrieved 2007-05-10. 
  21. ^ "Jury awards $16 million to family in fatal radio prank". LA Times. October 29, 2009. http://latimesblogs.latimes.com/lanow/2009/10/jury-awards-16-million-in-radio-prank-that-left-sacramentoarea-woman-dead-.html. Retrieved 2010-01-31. 
  22. ^ "Woman died from 'too much water'". BBC News. 2008-12-12. http://news.bbc.co.uk/1/hi/england/bradford/7779079.stm. 
  23. ^ "Reasons for dispensing with the holding of an inquest". http://www.erowid.org/chemicals/mdma/mdma_health5.shtml. Retrieved 2007-05-10. 
  24. ^ "Doctors: Marathoner Died From Too Much Water". August 13, 2002. http://www.thebostonchannel.com/newscenter5/1610699/detail.html. Retrieved 2007-05-10. 
  25. ^ "District Officer Dies After Bike Ride: Over-Hydration Cited as Factor". The Washington Post. August 11, 2005. http://www.washingtonpost.com/wp-dyn/content/article/2005/08/10/AR2005081001460.html. Retrieved May 27, 2010. 
  26. ^ Grice, Elizabeth (August 21, 2003). "My battle with the bottle". The Daily Telegraph (London). http://www.telegraph.co.uk/culture/theatre/drama/3600987/My-battle-with-the-bottle.html. 
  27. ^ http://www.thisislondon.co.uk/news/article-5603390-actor-tells-of-water-overdose.do
  28. ^ "Lost hiker died because he drank too much water". NZ Herald. AAP. Sep 17, 2012. http://www.nzherald.co.nz/world/news/article.cfm?c_id=2&objectid=10834669. Retrieved September 18, 2012. 

External links