ChiroACCESS Article

How Much Drinking Water is too Much?

This information is provided to you for use in conjunction with your clinical judgment and the specific needs of the patient.

ChiroACCESS Editorial Staff



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December 6, 2013

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The question of how much drinking water is needed for good health is a complicated one.  In reality the question should be how much fluid do we need as the Mayo clinic noted:

Although the "8 by 8" rule isn't supported by hard evidence, it remains popular because it's easy to remember.  Just keep in mind that the rule should be reframed as: "Drink at least eight 8-ounce glasses of fluid a day," because all fluids count toward the daily total.

The proper amount of fluid required varies depending upon a number of factors.  The most common are climate, disease conditions including fever or fluid loss, and strenuous work and athletic activity.  As nontechnical as this sounds, the body has an excellent feedback system and most experts suggest a total fluid intake around 6-8 glasses and to simply drink when you are thirsty.  Drinks with diuretic properties like coffee, tea, and alcohol may increase the need for other fluids.

Giving patients advice to drink 8 glasses of water rather than fluids a day can actually have harmful effects.   Individuals who already consume large amounts of fluids (from fruits, vegetables, etc.) have no need of adding an additional 8 glasses of water.  Most people are not aware that drinking excessive water can have serious adverse health effects and in rare cases result in coma and death.  The abstracts below are examples from the literature that document some of the more severe cases of water intoxication.

  These mini-reviews are designed as updates and direct the reader to the full text of current research.  The abstracts presented here are no substitute for reading and critically reviewing the full text of the original research.  Where permitted we will direct the reader to that full text.

Forensic aspects of water intoxication: four case reports and review of relevant literature.  [Link]

Forensic Sci Int. Date

Radojevic N, Bjelogrlic B, Aleksic V, Rancic N, Samardzic M, Petkovic S, Savic S.
Department of Forensic Medicine, Clinical Centre of Montenegro, Podgorica, Montenegro.

Water intoxication (WI) is a rare condition that originates from over-consumption of water, with a potentially fatal outcome. Increased water intake (polydipsia) is followed by urination of high amount of diluted urine (polyuria) which are the main initial symptoms of WI. We present four case reports of WI. Two of them are unusual pediatric clinical cases using medical documentation and police case files, one of which is related to child abuse, and the other to a psychiatric disorder. The other two cases are fatal adult cases submitted to autopsy from a psychiatric hospital. Also, we present a diagnostic algorithm for polydipsia and polyuria before death. WI is usually seen in patients with psychiatric disorders, victims of child abuse or torture, drug abusers or it can be iatrogenically induced.

Acute water intoxication during military urine drug screening.  [Link]

Mil Med. 2011 Apr;176(4):451-3.

Tilley MA, Cotant CL.
Wilford Hall Medical Center, 2200 Bergquist Drive, Suite 1, Lackland AFB, TX 78236, USA.

Random mandatory urine drug screening is a routine practice in the military. The pressure to produce a urine specimen creates a temptation to consume large volumes of water, putting those individuals at risk of acute water intoxication. This occurs when the amount of water consumed exceeds the kidney's ability to excrete it, resulting in hyponatremia owing to excess amount of water compared to serum solutes. The acute drop in serum osmolality leads to cerebral edema, causing headaches, confusion, seizures, and death. There has been increasing awareness of the danger of overhydration among performance athletes, but dangers in other groups can be underappreciated. We present the case of a 37-year-old male Air Force officer who developed acute water intoxication during urine drug screening. Our case demonstrates the need for a clear Air Force policy for mandatory drug testing to minimize the risk of developing this potentially fatal condition.

Hyponatremic encephalopathy after excessive water ingestion prior to pelvic ultrasound: neuroimaging findings.  [Link]

Intern Med. 2010;49(16):1807-11. Epub 2010 Aug 13.

Yalcin-Cakmakli G, Karli Oguz K, Shorbagi A, Funda Bas D, Ergan-Arsava B, Kunt M, Topcuoglu MA.
Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.

We report two patients with acute hyponatremic encephalopathy which developed after massive water ingestion for pelvic ultrasound and emphasize the findings of magnetic resonance (MR) imaging including diffusion-weighted imaging (DWI). Both subjects had completely recovered within 24 hours following fluid restriction and salt replacement. MR imaging revealed cortical sulcal narrowing, restricted diffusion and sulcal T2 hyperintensity along with diffuse pial enhancement suggesting diffuse cerebral cortical cytotoxic edema and blood-brain barrier breakdown. In addition to the first illustration of multimodality MR imaging features of water-intoxication, these two cases also highlight the need for standardized practice on the quantity of water intake recommended to distend the bladder for pelvic ultrasound, especially in patients at risk for serum inappropriate ADH syndrome-related hyponatremia.

Iatrogenic water intoxication after pelvic ultrasonography imaging.  [Link]

Am J Emerg Med. 2010 Mar;28(3):385.e1-3.

Camkurt MA, Coskun F, Aksu NM, Akpinar E, Ay D.
Hacettepe University School of Medicine Emergency Department, Ankara, Turkey.

Ultrasound (US) is a simple, easily accessible, and noninvasive method. Thus, it is commonly used. The bladder should be sufficiently filled to acquire pelvic images by US. This report describes water poisoning in 3 patients with no hepatic, cardiac, or renal disease. Both patients had a history of excessive fluid intake.

[Hyponatremia: from physiopathology to practice].  [Link]

Rev Med Interne. 2010 Apr;31(4):277-86.

Passeron A, Dupeux S, Blanchard A.
Service de médecine interne, AP-HP, hôpital européen Georges-Pompidou, Paris, France.

Hypotonic hyponatremia is the most common electrolyte abnormality encountered in hospitalized patients. It is often asymptomatic but associated with increased mortality and morbidity. Prompt recognition of the underlying cause using a systematic physiology based approach and careful evaluation the chronicity of the hyponatremia is mandatory for an optimal management. One should first document hypotonicity, and then assess the renal response to hypotonicity to exclude water intoxication, and the extracellular volumes. The further step will identify hyponatremia due to volemic stimulation of vasopressin associated to extracellular dehydration (corrected by isotonic saline infusion) or to oedematous states. After exclusion of hypocorticism and hypothyroidism, one would conclude to inappropriate secretion of antidiuretic hormone whose etiology would have to be established. The use of hypertonic saline solutions should be restricted to the treatment of acute and severe hyponatremia with evidence of brain damage. Chronic hyponatremia should be correct slowly to avoid the risk of osmotic demyelination syndrome. Water restriction is commonly recommended in inappropriate secretion of antidiuretic hormone or in hypervolemia with a questionable effectiveness. The recent development of vasopressin receptor antagonists (vaptans) will modify our therapeutic approaches. Yet, further studies are needed to document their additional impact on morbidity and mortality.

Exercise-associated hyponatremia: overzealous fluid consumption.  [Link]

Wilderness Environ Med. 2009 Summer;20(2):139-43.

Rogers IR, Hew-Butler T.
Sir Charles Gairdner Hospital, Nedlands, Western Australia.

Exercise-associated hyponatremia is hyponatremia occurring during or up to 24 hours after prolonged exertion. In its more severe form, it manifests as cerebral and pulmonary edema. There have now been multiple reports of its occurring in a wilderness setting. It can now be considered the most important medical problem of endurance exercise. The Second International Exercise-Associated Hyponatremia Consensus Conference gives an up-to-date account of the nature and management of this disease. This article reviews key information from this conference and its statement. There is clear evidence that the primary cause of exercise-associated hyponatremia is fluid consumption in excess of that required to replace insensible losses. This is usually further complicated by the presence of inappropriate arginine vasopressin secretion, which decreases the ability to renally excrete the excess fluid consumed. Women, those of low body weight, and those taking nonsteroidal anti-inflammatory drugs are particularly at risk. When able to be biochemically diagnosed, severe exercise-associated hyponatremia is treated with hypertonic saline. In a wilderness setting, the key preventative intervention is moderate fluid consumption based on perceived need ("ad libitum") and not on a rigid rule. (Editor's Note: This paper was written at my request in an effort to increase awareness of this important clinical entity among members of the wilderness community, many of whom are involved in activities that place them at risk of its development. I thank the authors for their diligent efforts.)

[Drink when thirsty--too much water can be danger to life].  [Link]

Lakartidningen. 2009 Feb 11-17;106(7):448-9.

Fagrell B.
Karolinska institutet, Karolinska Universitetssjukhuset, Solna.

The treatment of hyponatremia.  [Link]

Semin Nephrol. 2009 May;29(3):282-99.

Sterns RH, Nigwekar SU, Hix JK.
Department of Medicine, Rochester General Hospital, Rochester, NY 14534, USA.

Virtually all investigators now agree that self-induced water intoxication, symptomatic hospital-acquired hyponatremia, and hyponatremia associated with intracranial pathology are true emergencies that demand prompt and definitive intervention with hypertonic saline. A 4- to 6-mmol/L increase in serum sodium concentration is adequate in the most seriously ill patients and this is best achieved with bolus infusions of 3% saline. Virtually all investigators now agree that overcorrection of hyponatremia (which we define as 10 mmol/L in 24 hours, 18 mmol/L in 48 hours, and 20 mmol/L in 72 hours) risks iatrogenic brain damage. Appropriate therapy should keep the patient safe from serious complications of hyponatremia while staying well clear of correction rates that risk iatrogenic injury. Accordingly, we suggest therapeutic goals of 6 to 8 mmol/L in 24 hours, 12 to 14 mmol/L in 48 hours, and 14 to 16 mmol/L in 72 hours. Inadvertent overcorrection owing to a water diuresis may complicate any form of therapy, including the newly available vasopressin antagonists. Frequent monitoring of the serum sodium concentration and urine output are mandatory. Administration of desmopressin to terminate an unwanted water diuresis is an effective strategy to avoid or reverse overcorrection.

Symptomatic hyponatremia after voluntary excessive water ingestion in a patient without psychiatric problems.  [Link]

Endocr J. 2007 Aug;54(4):643-5.

Hiramatsu R, Takeshita A, Taguchi M, Takeuchi Y.
Toranomon Hospital Endocrine Center, 2-2-2 Toranomo Minato-ku, Tokyo 105-8470, Japan.

Water intoxication usually happens in patients with a psychiatric problem, who are subject to compulsive water ingestion, and during clinical examinations, such as uroflowmetry, and is seldom observed in ordinary people. Here we report a patient with severe hyponatremia due to voluntary water drinking coexisting with no psychiatric problems. The case presented clinically significant hyponatremia 124 mmol/L without any signs of dehydration after voluntary ingestion of 4000 ml of water over 3 hours. She normally responded to ingestion of 1000 ml of water over 20 min after recovery from hyponatremia, and did not meet the diagnostic criteria of SIADH. She was not a compulsive drinker. The present case suggests that one should consider water intoxication as a cause of hyponatremia in a patient without signs of dehydration, even if he/she does not have a history of compulsive water ingestion.

[Water is a dangerous poison... Two cases of hyponatremia associated with spinning and extensive fluid intake].  [Link]

Lakartidningen. 2008 May 28-Jun 3;105(22):1650-2.

Lorraine-Lichtenstein E, Albert J, Hjelmqvist H.
Anestesi- och intensivvårdskliniken, Danderyds sjukhus, Stockholm.

H2O coma.  [Link]

Neurocrit Care. 2007;6(1):67-71.

Stiefel D, Petzold A.
Department of Paediatrics, Civico Hospital, Via Tesserete 46, CH-6903 Lugano, Switzerland.

INTRODUCTION: Water intoxication is a rare cause of coma. The leading causes of excessive hydration are endurance exercise, drug abuse, iatrogenic, cerebral salt wasting, or psychiatric conditions. Self-induced water intoxication in an otherwise healthy person is exceedingly rare.

METHODS: Single patient case report and review of the literature.

RESULTS: We describe a previously fit and healthy 13-year-old girl who was admitted to the Accident and Emergency department in a comatose state following an unwitnessed seizure. On examination she had a fluctuating Glasgow Coma Score, bilateral mydriatic pupils that responded poorly to light, and an upgoing right plantar. Blood pressure, pulse rate, and oximetry, as well as body mass index, were normal. Routine blood examination revealed hyponatremia, hypochloremia, and a low hematocrit. Water intoxication was suspected and confirmed by reduced urine sodium, serum, and urine osmolality. The computed tomographic brain scan, lumbar puncture opening pressure, and cerebrospinal fluid examination were all normal. She regained consciousness and was fully orientated within 24 hours following intravenous NaCl administration. In this case, thirst without any other apparent pathology led to voluntary water intoxication.

CONCLUSIONS: Our case illustrates the classic picture of self-induced water intoxication in a previously fit and healthy patient.

Too much of a good thing? The danger of water intoxication in endurance sports.  [Link]

Mil Med. 2001 May;166(5):405-10.

O'Brien KK, Montain SJ, Corr WP, Sawka MN, Knapik JJ, Craig SC.
Department of Family Practice and Community Medicine, Martin Army Community Hospital, Fort Benning, GA 31905, USA.

This report describes a series of hyponatremia hospitalizations associated with heat-related injuries and apparent over-hydration. Data from the U.S. Army Inpatient Data System were used to identify all hospitalizations for hyposmolality/hyponatremia from 1996 and 1997. Admissions were considered as probable cases of overhydration hyponatremia if this was the only, or primary, diagnosis or if it was associated with any heat-related diagnosis. Seventeen medical records were identified, and the events leading to hospitalization were analyzed. The average serum sodium level was 122 +/- 5 mmol/L (range, 115-130 mmol/L). All 17 patients were soldiers attending training schools. Seventy-seven percent of hyponatremia cases occurred in the first 4 weeks of training. Nine patients had water intake rates equal to or exceeding 2 quarts per hour. Most patients were in good health before developing hyponatremia. The most common symptoms were mental status changes (88%), emesis (65%), nausea (53%), and seizures (31%). In 5 of 6 cases in which extensive history was known, soldiers drank excess amounts of water before developing symptoms and as part of field treatment. The authors conclude that hyponatremia resulted from too aggressive fluid replacement practices for soldiers in training status. The fluid replacement policy was revised with consideration given to both climatic heat stress and physical activity levels. Field medical policy should recognize the possibility of overhydration. Specific evacuation criteria should be established for exertional illness.

Exertional heat illness and hyponatremia in hikers.  [Link]

Am J Emerg Med. 1999 Oct;17(6):532-9.

Backer HD, Shopes E, Collins SL, Barkan H.
Department of Emergency Medicine, Kaiser Permanente Medical Center, Hayward, CA 94545, USA.

We compared clinical presentation and course of exercise-associated hyponatremia with heat exhaustion among summertime hikers in Grand Canyon National Park. Cases were selected from among hikers who requested medical help from the National Park Service Emergency Medical Service (EMS) or who presented to the medical clinic on the rim of the canyon with complaints related to exercise in the heat. Of 44 patients who had serum samples analyzed, 7 had hyponatremia with clinically significant symptoms and serum sodium levels <130 mmol/L: 3 had grand mal seizures, 2 had other major central nervous system disorders, and 2 had minor neurological symptoms. Seizures and change of mental status distinguished hyponatremia, (P = 0.0002). Indirect evidence suggests that hyponatremic patients were hyperhydrated. Other common symptoms included nausea, vomiting, headache, and dizziness, but these symptoms did not predict the level of serum sodium. When exercise in the heat is prolonged, hyponatremia is suggested either by altered mental status or by seizures without hyperpyrexia or hypoglycemia. No mortality or long-term morbidity occurred in any of these cases of hyponatremia.

Death from hyponatremia as a result of acute water intoxication in an Army basic trainee.  [Link]

Mil Med. 1999 Mar;164(3):234-8.

Garigan TP, Ristedt DE.
Winn Army Community Hospital, Fort Stewart, GA 31314, USA.

Several reports during the past 15 years have described hyponatremia as a result of excessive water intake by athletes during endurance races. The high rates of fluid consumption have been attributed to the desire of athletes to prevent heat injury. The military has adopted guidelines for programmed drinking to maintain performance and minimize the risk of heat casualties. As military personnel increase their fluid intake, their risk of hyponatremia as a result of water overload increases. A potentially life-threatening complication is acute water intoxication. We report the first known death of an Army basic trainee as a result of acute water intoxication. The misinterpretation of his symptoms as those of dehydration and heat injury led to continued efforts at oral hydration until catastrophic cerebral and pulmonary edema developed.

Drowning in the desert: exercise-induced hyponatremia at the Grand Canyon.  [Link]

J Emerg Nurs. 1997 Dec;23(6):586-90.

Shopes EM.
Forest Country Anesthesia, Flagstaff Medical Center, Arizona, USA.

Excessive water drinking and cataract formation: a case report.  [Link]

Metab Pediatr Syst Ophthalmol. 1993;16(1-2):12-4.

Beiran I, Pikkel J, Miller B.
Department of Ophthalmology, Rambam Medical Center, Haifa, Israel.

We report a case of a 46-year-old man who developed mature cataract in one eye and nearly mature cataract in his other eye over a 14-month period. No genetic, traumatic, or toxic etiology or intraocular pathology or history of irradiation were present. The patient had intentionally been drinking 15 liters of water a day for 11 months, up until 3 months prior to his admission, and 5 liters a day thereafter, until his admission. During his hospitalization he was found to suffer from insulin-dependent diabetes mellitus. The rest of his medical work-up was found to be normal. We suggest that the huge water overload put on his lens played a role in the premature and rapid cataract formation.

Excessive water ingestion and repeated seizures: the domino effect.  [Link]

Arq Neuropsiquiatr. 2008 Sep;66(3A):552-3.

Santos-Soares PC, Bacellar A, Povoas HP, Oliveira-Filho J, Filgueiras NM, Brito AF.
Neuro/Cardio ICU, Hospital Espanhol, Salvador, BA, Brazil.
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