Tox-2 Flashcards
How do you treat salt toxicity?
Slow rehydration and furosemide (to prevent pulmonary edema)
What other differentials must you consider when suspecting salt toxicity?
Polio, lead, pesticides, encephalitis
What are examples of products that contain phenoxyacetic acid herbicides?
2,4-D (Scott’s weed and feed), 2,4,5-T, Silvex
How toxic are phenoxyacetic acid herbicides?
Low toxicity in most animals, though Silvex is very toxic
What are the clinical signs of phenoxyacetic acid herbicide toxicity?
GI effects (vomiting, diarrhea +/- blood, ulcerations, muscle effects, renal tubular degeneration, hepatic necrosis
How do you treat phenoxyacetic acid herbicide toxicity?
GI decontamination (emesis, lavage, activated charcoal, cathartic), ion trapping with NaHCO3 if kidneys normal to enhance excretion; prognosis is good with treatment
What is the mechanism of toxicity of ergot alkaloids?
Dopamine and serotonin receptor agonists
What are the clinical signs of ergot alkaloid toxicity?
Reduced feed intake and weight gain, heat intolerance, retain winter coat, necrotizing ergotism, fat necrosis, poor reproductive performance
How do you diagnose ergot alkaloid toxicity?
Evidence of sclerotia in feed, fescue in forage matter, chemical analysis of feed and forage
What is the gold standard treatment for ergot alkaloid toxicity?
Metoclopromide and domperidone to increase prolactin secretion and normalize gestation in mares
Ionophores are approved for use in dairy cattle to…
Improve efficiency of milk production
What is the mechanism of action of ionophores?
Increase intracellular Na+ and Ca++, leading to mitochondrial swelling and cell death, especially in muscle (remember it’s target is the mitchondrial MEMBRANE)
What is a common sign of ionophore toxicity?
Anorexia
What clinical signs are associated with ionophore toxicity in horses?
Anorexia, colic, profuse sweating on flanks; may be uncoordinated and weak
What clinical signs are associated with ionophore toxicity in cattle?
Same as horses but with diarrhea and respiratory difficulty
At necropsy, what are the characteristics of ionophore toxicity?
Hemorrhage in the hear, pale heart, infiltration of macrophages in the muscle
How do you diagnose ionophore toxicity?
Evidence of muscle damage on serum biochem, decreased K and Ca, chemical analysis of feeds and liver
What other differentials must you consider when suspecting ionophore toxicity?
Colic, vitamin E and Se deficiency, white snakeroot, blister beetle, gossypol, botulism
How do you treat ionophore toxicity?
No specific treatment or antidote; change feed, offer supportive therapy, anti-oxidants
What is the most common cause of tetanus?
Spores in puncture wounds
What is the mechanism of action of tetanus?
Blocks release of GABA and glycine (inhibitory neurotransmitters) resulting in overstimulation of muscles leading to stiffness
What are the clinical signs of tetanus?
Stiffness and reluctance to move, twitching and tremors, lockjaw, unsteady gait, bloat in ruminants
What is the treatment for tetanus?
Antitoxin if very early, supportive therapy; prognosis is very poor
First generation anticoagulants, such as warfarin, have a short/long half-life with a low/high potency?
Short half-life, low potency
Second generation anticoagulants, such as brodifacoum, have a short/long half-life with a low/high potency?
Long half-life, high potency
What is the mechanism of action of anticoagulants?
Inhibits vitamin K1 epoxide reductase preventing formation of vitamin K dependent clotting factors
What are the clinical signs of anticoagulant toxicity?
Delayed onset; depression, anorexia, and anemia, dyspnea, nosebleeds, bleeding gums, and bloody feces, hemorrhage and hematoma
What are the three most common methods of diagnosing an anticoagulant toxicity?
History of exposure, evidence of coagulopathy, response to vitamin K1 therapy (will also have prolonged PT)
How do you treat anticoagulant toxicity?
GI decontamination if recent; Vitamin K administration (low doses/short time for first gens, high doses/long time for second gens); transfusion if necessary
What are the common sources of nitrates that can cause nitrate toxicosis?
Fertilizers, plants, water
What is the mechanism of action of nitrates?
Nitrate -> nitrite -> vasodilation and ferrous iron+Hgb -> methemoglobin -> oxygen starvation of tissues
What are the hallmark clinical signs of nitrate toxicosis?
Cyanosis, brown blood; with serious toxicity, ataxia, seizures, coma, death
How do you diagnosis nitrate toxicosis?
Nitrate levels in feed or water; save eye for analysis after death
What treatment is most effective in nitrate toxicosis of ruminants?
IV methylene blue (urine will become dark green)
What treatment is most effective in nitrate toxicosis in cats and horses?
Ascorbic acid
What plants are common sources of cardiac glycosides?
Foxglove, oleander, lily of the valley
What is the mechanism of action of cardiac glycosides?
Inhibits Na-K ATPase through competition with K for binding sites
What are the clinical signs of cardiac glycoside toxicity?
Trembling, staggering and dyspnea in grazing animals; racing heart rate and rhythm/arrhythmia, weak pulse
How do you diagnose cardiac glycoside toxicity?
Hx, access to plants, CSs, and vomit analysis
What is the antidote for digoxin and similar glycosides?
Digoxin immune Fab fragments (i.e., digibind)