Water deprivation--Na ion toxicosis Flashcards Preview

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Flashcards in Water deprivation--Na ion toxicosis Deck (23)
1

Sources?

  • Feeding brine, whey, or garbage
  • Ingestion of salt-licks or ice-melts
  • Drinking water might contain salt
  • All factors that cause excess Na and water deprivation
    • Over crowding
    • Frozen water
    • Unpalatable (medicated) water
    • Lack of water

2

T/F: Salt taste is attractive to animals and has a mild irritant effect on mucous membranes

TRUE

3

What is the normal level of NaCl in feed?

About 0.5-1.0%

4

What are the acute oral lethal doses of salt?

  • Horses, cattle, swine: ~2.2g/kg
  • Sheep: 6g/kg
  • Dogs: 4g/kg (depending on water intake)

5

T/F: Animals can only tolerate up to 10% salt in feed, even with free access to water

FALSE--animals can tolerate more than 10% salt in feed if they have free access to water

6

Which species are the most susceptible to salt poisoning?

Pigs, cattle, and poultry; dogs are less susceptible

7

Salt is rapidly absorbed from the ____ and is distributed ____.

Salt is rapidly absorbed from the GI tract and is distributed all over the body.

8

Does sodium enter the brain? If so, how?

Yes--sodium enters the brain by passive diffusion and is removed by active transport

9

What happens to excess absorbed sodium?

When might this not occur, and what will be the result?

  • The excess of absorbed sodium following large dietary intake is rapidly excreted in urine as long as there is enough water
  • Excess sodium (and water deprivation) results in hypertonicity of the blood and toxicosis

10

What are the normal Na levels in plasma and CSF?

Plasma = 135-145 mEq/L

CSF = 130-140 mEq/L

11

Restricted water intake and dehydration increases Na levels in plasma and CSF to what?

Plasma = 150-190 mEq/L

CSF = 145-185 mEq/L

12

What does high Na in the brain inhibit?

Inhibits anaerobic glycolysis --> lack of energy necessary for active transport of Na

13

What occurs when sodium is trapped in the brain?

Na trapped in the brain attracts water b/c the osmotic gradient--> cerebral edema

14

General clinical signs?

  • Early constipation and thirst
  • Vomiting, PU, metabolic acidosis
  • Intermittent convulsive seizures
    • Lasts from 0.5 to 2-3 min
    • Interrupted by other signs
    • Not elicited by external stimuli
  • Circling, pivoting, head-pressing
  • Blindness and deafness
  • Inability to eat and drink or even recognize the feed or water

15

Clinical signs in poultry?

Poultry only show depression, ascites, and collapse

16

Gross lesions?

  • Gastric congestion or inflammation with pinpoint ulcers
  • Fluid in body cavities and organ edema
  • Prominent cerebral edema

17

Histopathological lesions?

Eosinophilic meningoencephalitis (filling of cerebral and meningeal perivascular spaces w/ eosinophils) is pathognomonic in pigs only, if the animal dies early

18

Laboratory diagnosis?

  • Serum and CSF (or ocular fluid) Na concentrations are 160 mEq/L or more
  • Brain Na concentrations above 2000ppm support diagnosis
  • Salt in feed

19

Diagnosis

History, encephalitic signs, lesions, and lab diagnosis

20

DDx?

  • Encephalitic diseases
    • Trauma
    • Tumor
    • Heat stroke
    • Viral encephalomyelitic conditions
  • Chlorinated hydrocarbon insecticides
  • Roxarsone
  • Pseudorabies

21

Treatment?

  • Giving small amounts of fresh water (0.5% of body wt.) gradually over 2-3 days, if the animal is able to drink
  • IV fluids (5% dextrose) and furosemide in small animals
  • Anticonvulsants in small animals

22

T/F: Giving water in large amounts as treatment may kill the animal by aggravating cerebral edema

TRUE

23

Prognosis?

Poor

Mortality rate is ~50%