Plant Related Toxicants Flashcards Preview

RUSVM Toxicology 2016 > Plant Related Toxicants > Flashcards

Flashcards in Plant Related Toxicants Deck (58)
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1
Q

What is the is the conversion of Nitrate to Nitrite and where does it take place?

A

Nitrate (NO3) is absorbed from the soil by the plant and converted to Nitrite (NO2)
This can also happen in the blood and in the rumen

2
Q

What converts Nitrate to Nitrite?

A

Nitrate reductase

3
Q

What leads to accumulation of the nitrate in the plant?

A

the rate of Nitrate to Nitrite is reduced with the continuation of Nitrate uptake from the soil

4
Q

What factors favor plant nitrate accumulation?

A

High Nitrate or ammonia in the soil
Soil conditions: Rain, Moisture, acid soil, low soil molybdenum, etc
Decreased light reduces activity of nitrate reductase
Use of phenoxy acetic acid herbicides
Stage of plant growth

5
Q

What parts of the plant contain the highest concentration of Nitrate?

A

The stalks

6
Q

What plant species accumulate nitrate?

A
Sweet clover 
alfalfa
wheat 
corn 
Pigweed
Oats
Beets
Johnson grass
Sudan grass
Milo 
Lamb's quarters
Sunflower
7
Q

what is the use of Nitrates?

A

Fertilizer

Sodium Nitrite IV as a vasodilator

8
Q

What animals are susceptible to nitrate poisoning from Sodium NitrIte IV?

A

Horses

9
Q

What is the source of Nitrate or Nitrite poisoning?

A

Rapid ingestion of forages or hays containing high amount of nitrate
Accidental ingestion of feeds or water contaminated with nitrate
Overdose with Nitrite IV

10
Q

Properties of Nitrates?

A

Water Soluble

Salty - Palatable

11
Q

What form of Nitrate or Nitrite is more toxic?

A

Nitrite is 10 times more toxic than nitrate

12
Q

What age of animals are more susceptible to Nitrate poisoning?

A

greater than 3 months of age

2-3 years old

13
Q

What diseases cause an increase in toxicity of Nitrates?

A

Anemia and Methemoglobinemia

14
Q

What is the half life of Nitrite?

A

Less than 1 hour

15
Q

What is the half life of Nitrates?

A

4-48 hours

16
Q

What is the Acute mechanism of action for Nitrate Poisoning?

A

One molecule of Nitrite interacts with two molecules of hemoglobin resulting in oxidation off ferrous iron to ferric and conversion of hemoglobin to methemoglobin

17
Q

What is the chronic mechanism of action for Nitrate poisoning?

A

Abortion due to decreased progesterone
weak
weight loss
wasting

18
Q

What are the clinical signs of Nitrate Poisoning?

A
Sudden death 
rapid breathing 
restlessness
apprehension 
dyspnea
weakness
sternal recumbency
cyanosis 
terminal convulsion due to not enough O2 
Abortion due to fetal anoxia
19
Q

What are the lesions associated with Nitrate Poisoning?

A

Congestion of organs

Brown-chocolate color of blood

20
Q

What is the specimen of choice for nitrate poisoning in dead animals?

A

Ocular Fluid

21
Q

What are the specimens for nitrate poisining in live animals?

A

Serum
Plasma
urine
rumen contents

22
Q

What is the test for nitrate in forages, rumen contents, and water?

A

Diphenylamine test

23
Q

What is the color of the positive result for the Diphenylamine test for Nitrate poisoning?

A

Dark blue color

24
Q

What is the differential diagnosis for Nitrate Poisoning?

A

Acetominophen in cats

25
Q

What is the treatment for Nitrate Poisoning?

A

Methylene blue 1% IV for ruminanats and monograstics

Activated charcoal, ruminal lavage with cold water, oral antibiotics inhibit rumen microflora and nitrate reductase

26
Q

What is the prognosis for Nitrate Poisoning?

A

Die before treatment because death is rapid

27
Q

What is the source of Cyanide Poisoning in Large animals?

A

Ingestion of cyanogenic plants

28
Q

What is the source of Cyanide Poisoning in small animals?

A

Hydrogen cyanide and cyanide salts
Hydrogen cyanide as a fumigant rodenticide
Sodium nitroprusside used as a hypotensive
Combustion of plastic compounds

29
Q

What are the cyanogenic plants?

A
Wild Cherry 
Sudan grass
Johnson grass
Sorghums 
Apples
plums 
lima beans
cassava roots
30
Q

What are the properties of Cyanide Poisoning?

A

Volatile gas
characteristic bitter almond odor
CN radicals form complexes with ferric ion, cupric, and molybdenum

31
Q

What is the effect of Thiocyanate SCN?

A

antithyroid effect

32
Q

What type of toxin is Cyanide?

A

Highly Toxic

33
Q

What causes the release of Cyanide from cyanogenic plants?

A

Hydrolysis by the rumen microflora

34
Q

What cause the plant to release cyanide?

A

Stress

Plant damage

35
Q

How is cyanide released from the plant during stress?

A

Beta-glucosidase causes hydrolysis of cyanogenic glycosides and release of cyanide

36
Q

Where do cyanogenic glycosides accumulate the most?

A

The seeds

37
Q

What soil condition causes an increase in glycosides?

A

High Nitrogen

Low Phosphorus

38
Q

Where is cyanide rapidly absorbed from?

A

GI tract
Skin
inhalation

39
Q

What is the mechanism of action of cyanide poisoning?

A

CN in the blood and tissues binds with ferric iron and cupric copper of the mitochondrial cytochrome oxidase blocking the electron transport and inhibits the cells to utilize the available oxygen resulting in histotoxic anoxia

40
Q

What are the clinical signs of acute poisoning?

A
rapid onset
Die without manifesting clinical signs 
Tachypnea 
severe panting 
gasping 
salivation 
lacrimation 
urination 
defecation 
severe colic 
vomiting 
bright red mucous membranes
41
Q

What are the chronic clinical signs of Cyanide Poisoning?

A

Posterior paralysis
urinary incontinence
cystitis
constipation

42
Q

What are the lesions associated with Cyanide Poisoning?

A

Mucous membranes are bright red and blood is cherry red

Congestion and petechial hemorrhages of the GI tract and lungs

43
Q

What is the danger of cyanide poisoning?

A

could be poisoned during necropsy from opening the rumen

44
Q

What is the test for Cyanide Poisoning?

A

Sodium picrate paper test

45
Q

What is the differential diagnosis for Cyanide Poisoning?

A

Carbon Monoxide

46
Q

What is the treatment for Cyanide Poisoning?

A
Sodium Nitrite IV
Sodium thiosulfate IV
Sodium Thiosulfate Oral 
Oxygen therapy 
Vinegar in cold water orally to slow microbial hydrolysis
47
Q

What are the plants containing Soluble oxalates?

A
Pigweed
Beet
Lamb's quarters
Halogeton 
Sorrel 
Soursop 
Greasewood
48
Q

What species are most susceptible to soluble oxalate poisoning?

A

Sheep

Cattle

49
Q

Where does soluble oxalates accumulate in plants?

A

leaves

50
Q

What decreased toxicity of soluble oxalate poisoning?

A

Calcium or calcium rich diet

51
Q

What increases toxicity of soluble oxalate poisoning?

A

oxalate-producing fungi

52
Q

What are the toxicokinetics of soluble oxalate poisoning?

A

Soluble oxalates can be metabolized to a certain extent in the rumen to carbonates and bicarbonates
Calcium rich diet inhibit absorption by forming insoluble calcium oxalates which are excreted in feces

53
Q

What is the mechanism of action for soluble oxalate poisoning?

A

soluble oxalates combine with calcium ion to form insoluble calcium oxalate leading to hypocalcemia
Precipitation of calcium oxalates crystals in the kidney tubules causing kidney damage and necrosis

54
Q

What are the clinical signs of soluble oxalate poisoning?

A

depression
muscle twitching
muscle weakness
head and neck pulled to one side in sheep ( like milk fever in cattle)
Blood tinged froth around the mouth
Convulsions if the calcium is deposited in the brain
Calcium oxalate precipitation in renal tubules lead to fatal renal tubular toxicosis

55
Q

What are the lesions associated with soluble oxalate poisoning?

A

The mouth and esophagus filled with blood tinged froth
Kidneys show dark red cortex and medulla separated by a gray line from accumulation of oxalate crystals in the renal tubules

56
Q

What are the laboratory findings associated with soluble oxalate poisoning?

A

Presence of Calcium oxalate crystals in the kidneys

57
Q

What is a differential diagnosis for soluble oxalate poisoning?

A

Milk Fever

58
Q

What is the treatment for soluble oxalate poisoning?

A

Calcium gluconate IV
Saline-glucose to treat alkalosis
Supplementation of calcium salts
Supportive therapy