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Water intoxication
Synonym(s): water intoxication
Introduction
- Cause: rapid ingestion of water following a period of water deprivation.
- Signs: hemoglobinuria and neurological signs.
- Diagnosis: history (water deprivation followed by unlimited access to water) and neurological signs.
- Treatment: usually no intervention for mild to moderate cases. Intravenous hypertonic saline and furosemide can be given in severe cases.
- Prognosis: good for mild cases; guarded in animals with pronounced neurological signs.
Age predisposition
- Calves aged 2-10 months, particularly 3-5 months, are most commonly affected.
Cost considerations
- There may be stock and reproductive losses.
Pathogenesis
Etiology
- Dilutional hyponatremia can occur after ingestion of water at a rate in excess of the maximal excretory capacity of the kidney, or by ingestion of lesser amounts of water with impaired water excretion by the kidney.
- Water intoxication occurs following rapid ingestion of water and may occur under several circumstances:
- Following a period of water deprivation.
- Following strenuous exercise.
- During periods of high environmental temperatures.
Predisposing factors
Calves
- Water intoxication can occur in calves offered free access to water for the first time.
- Bucket-fed calves usually drink excessive water if it is offered in the manner in which they normally receive their milk.
- The volume ingested is limited by the capacity of the gut not by satiety and the rumen can hold a large volume of water compared with total body size.
- Chronic subclinical dehydration with increased environmental temperature, excess of fluid loss due to diarrhea or fever may predispose to water intoxication.
- Calves with oliguria or calves that fail to develop diuresis soon after water overload at are also at risk.
- Failure to provide both water and salt before weaning also predisposes to water intoxication.
Adult cattle
- Free access to water following a period of water deprivation. Even a short period of water deprivation (eg 1 day) followed by free access to water can result in water intoxication.
Pathophysiology
- Ingestion of too much water results in a positive water balance which leads to hemodilution.
- Water retention causes a dilution of body solutes and a reduction in osmolality.
- There is a rapid fall in serum sodium which results in increased water uptake by cells. This has multiple effects:
- Edema in the brain resulting in neurological signs.
- Hypotonicity of erythrocytes causes lysis resulting in hemoglobinuria and anemia.
Timecourse
- Onset is often rapid (<30 minutes) but can be longer (eg several hours).
- In mild cases recovery may occur in 3-4 hours, particularly if there is rapid diuresis after ingestion of excess water.
- In more severe cases recovery can take 2-5 days.
- Death generally occurs within 24-72 hours, but can occur within a few hours.
Epidemiology
- Water intoxication is a particular risk in hot weather when drinking water is limited or absent and then freely available.
- Water intoxication also occurs following a long transport period without access to water followed by rapid ingestion of water on reaching the final destination.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed Papers
- Recent references from PubMed and VetMedResource.
- Aitra S, Berisso R & Quiroga M A (2017) Intoxicación hídrica en Bovinos. [Water intoxication in cattle]. [online]. Thesis, Faculty of Veterinary Sciences, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Argentina. Available at: www.ridaa.unicen.edu.ar.
- Kawahara N, Ofuji S, Abe S, Tanaka A, Uematsu M & Ogata Y (2016) Water intoxication in adult cattle. Japan J Vet Res 64 (2),159-64 PubMed.
- Njoroge E M, Maribei J M, Mbugua P N & Njiru S M (1999) Water intoxication in cattle. J South Afr Vet 70 (4), 177-9.
- Maribei J M, Njoroge E M & Mbungua P N (1998) Clinical manifestation of experimental water intoxication in calves. Indian J Anim Sci 68 (6), 531-2 VetMedResource.
- Njoroge E M, Maribei J M & Mbugua P N (1997) Pathological changes in calves that died from experimental water intoxication. Onderstepoort J Vet Res 64, 111-114 PubMed.
- Gilchrist F (1996) Water intoxication in weaned beef calves. Can V J 37 (8), 490-1 PubMed.
- Shimizu Y, Naito Y & Murakami D (1979) Experimental study on the mechanism of hemolysis on paroxysmal hemoglobinemia and hemoglobinuria in calves due to excessive water intake. Japan J Vet Sci 41 (6), 583-592 PubMed.
- Gray T C (1970) Dehydration and water intoxication of range cattle. AVMA 157 (11), 1549-56 VetMedResource.
- Kirkbride C A & Frey R A (1967) Experimental water intoxication in calves. AVMA 151 (6), 742-6 PubMed.
- Lawrence J A (1965) Water intoxication in calves. SAVA 36, 277-278.
Organisation(s)
- ASPCA Animal Poison Control Center. www.aspca.org.
- Veterinary Poisons Information Service (VPIS). www.vpisglobal.com.