Deficiency of Both Sodium and Water
- Known as "salt depletion".
- The effects of the sodium (and therefore chloride) loss predominate.
- There is clinically detectable dehydration.
Causes
- Gastro-intestinal disorders.
- Gut crises.
- Intestinal obstruction.
- Torsions.
- Ruminal/ abomasal impaction.
- Excessive and prolonged sweating.
- Heat exhaustion.
- Renal disease.
- Nephritis.
- May also be associated with diabetes mellitus toxicity.
- Severe haemorrhage or burns.
- Result in severe plasma losses.
Effects
- Loss of sodium and chloride reduces the osmolality of extracellular fluid.
- There is a simultaneous loss of water.
- Water is transferred from the ECF to cells.
- Cells over-hydrate and may rupture.
- ECF volume falls.
- Resultis in haemoconcentration and peripheral circulatory failure.
- Renal involvement may become significant.
Water Excess
- Known as "water intoxication".
Causes
- Results from induced hypo-osmolality, e.g.
- Excessive administration of water to previously deprived animals.
- Administration of large volumes of water to animals with acute renal failure.
Effects
- The ECF osmolality is reduced.
- Water is transferred to the cells and they become "water-logged".
- Intracellular oedema in the CNS results in convulsions and death.