L4: CV and Hematopoietic Toxicity (Martyniuk)

Question 1

1st generation anticoagulant

Answer 1

• warfarin
• short half-life (15hr)
• low potency, requires multiple feedings

Question 2

2nf generation anticoagulant

Answer 2

• brodifacoum
• long half-life (20d)
• high potency, kills in single feeding

Question 3

anticoagulant MOA

Answer 3

inhibits vitamin K epoxide reductase and prevents formation of Vit. K dependent clotting factors
-results in excess inactive vitamin K and inability to clot

Question 4

CS of anticoagulant

Answer 4

(delayed onset as active vitamin K is used up)

-depression, anorexia, anemia initially –> dyspnea, hemorrhage, hematoma, prolonged bleeding

Question 5

3 most common methods of dx of anticoagulant

Answer 5

• Hx of exposure
• evidence of coagulopathy
• response to vitamin K therapy
• Tests: increased PT or PTT time

Question 6

Tx of anticoagulant

Answer 6

-Recent: emesis, adsorbent, cathartic therapy
-Vit. K administration
+/-transfusion if severe
-2nd generation requires longer tx than 1st generation

Question 7

nitrate toxicosis source and MOA

Answer 7

fertilizers and plants (Johnson grass, lambsquarters, Black nightshade, pigweed)
-converted to nitrite, which causes vasodilation and formation of MetHb

Question 8

nitrate toxicosis species susceptibility

Answer 8

pigs>cattle>sheep>horses

Question 9

CS of nitrate toxicosis

Answer 9

Based on lvl of MetHb:

70% - death

Question 10

Dx of nitrate toxicosis

Answer 10

• nitrate lvls in feed/water
• plasma, serum lvls
• eye post-mortem
• body cavity smells like ammonia

Question 11

Tx of nitrate toxicosis

Answer 11

• IV methylene blue for ruminants

- ascorbic acid in cats/horses

Question 12

cardiac glycosides source

Answer 12

avocados
lily of the valley
oleander
foxglove

Question 13

cardiac glycoside MOA

Answer 13

inhibits Na-K ATPase pump through competition w/ K for binding sites –> hyperkalemia, inc. intracellular Na

Question 14

CS of cardiac glycoside toxicity

Answer 14

trembling, staggering, dyspnea

racing heart rate and rhythm/arrythmia, weak pulse

Question 15

Dx of cardiac glycoside toxicity

Answer 15

based on Hx, access, symptoms, analysis of vomit

Question 16

Tx of cardiac glycoside toxicity

Answer 16

GI decon if recent
propranolol to tx arrythmias**
tx hyperkalemia with sodium bicarb, calcium glucamate
Digibind if propanolol ineffective (binds glycosides)

Question 17

cantharidin source

Answer 17

blister beetles found in alfalfa
Spanish fly
-usually affects horses

Question 18

cantharidin MOA

Answer 18

• inhibits protein phosphatases

- mucosal irritant

Question 19

CS of cantharidin toxicity

Answer 19

• colic, frequent urination, D contraction with heart beat, shock
• severe irritation and ulceration of oral, GI, and bladder
• cardiac toxicity

Question 20

Dx of cantharidin toxicity

Answer 20

alfalfa hay consumption
beetles in hay or stomach
hypocalcemia, inc. BUN
ulceration of mm
cardiac necrosis

Question 21

Tx of cantharidin toxicity

Answer 21

GI decon and protection (sucralfate), abx

Question 22

cyanide sources

Answer 22

wild cherry
white clover
fresh Sorghum spp.
fertilizers/pesticides/rodenticides
fumigants
combustion

Question 23

cyanide MOA

Answer 23

inhibition of cytochrome oxidase, which prevents cellular aerobic respiration

Question 24

CS of cyanide

Answer 24

-sudden death, dyspnea, weakness, tremors

Question 25

Dx of cyanide

Answer 25

- classic: cherry red blood that is slow to clot - stomach contents smell like almonds - Hx of ingestion

Question 26

Tx of cyanide toxicity

Answer 26

-INDUCE MetHb formation with sodium nitrite to bind cyanide -sodium thiosulfate to inc. form. of thiocyanate, which binds cyanide +/- tx MetHb with methylene blue

Question 27

methylxanthine source

Answer 27

(caffeine, theobromine, theophylline) | chocolate, coffee, meds

Question 28

methylxanthine MOA

Answer 28

- competitive antagonist of adenosine receptors, which mitigate inhibitory effects --> CNS stimulation, vasodilation, tachycardia - prevents Ca reuptake --> m. contractility - inhibits phosphodiesterase, inc. cAMP and GMP conc.

Question 29

CS of methylxanthine toxicity

Answer 29

- v/d, diuresis - hyperactivity - panting - tachycardia - ataxia - tremors, seizures - coma - death from arrythmia/resp. failure

Question 30

Dx of methylxanthine toxicity

Answer 30

- Chem. analysis of stomach contents, plasma, serum, urine or liver - theobromine in serum

Question 31

Tx of methylxanthine toxicity

Answer 31

- GI decon (emesis, act. charc.) - monitor EKG - tx seizures with diazepam or barbiturates - maintain resp. - fluid diuresis

Question 32

gossypol source

Answer 32

pigment glands of cottonseed - an oily substance - usually requires chronic exposure to cause toxicity - non-ruminants more sensitive

Question 33

gossypol MOA

Answer 33

- chelates iron and causes anemia - reduces protein availability - inhibits dehydrogenases leading to dec. energy and protein production; may also cause oxidative stress

Question 34

CS of gossypol toxicity

Answer 34

- weight loss, weakness, dyspnea - edema 2ary to heart failure - myocardial necrosis

Question 35

Dx of gossypol toxicity

Answer 35

- Hx of cottonseed ingestion - cardiac necrosis, edema, vacuoloization - chem. analysis

Question 36

Tx of gossypol toxicity

Answer 36

remove source high protein diet Vit. A, iron, lysine tx symptoms