Hematologic, Respiratory, Metabolic, and Cardio Toxins Flashcards
What is Melilotus spp?
Moldy sweetclover
What was isolated from moldy sweetclover?
Dicourmarol
What is the most common intoxication in small animals?
Anticoagulant rodenticides
What is found in 1st generation anticoagulant rodenticides?
Warfaring, pindone, chorophacinone
What is found in 2nd generation and longer anticoagulant rodenticides?
Bromadiolone, brodifacoum, diphacinone
What is the anticoagulant MOA?
Interferes with the conversion of vitamin K and its 2,3 epoxide
Inhibits carboxylation of coagulation proteins clotting factors 2, 7, 9, 10
Binds with plasma albumin and competes with other protein bound xenobiotics
Where does the metabolism of coumarins occur?
Liver
What species is the most susceptible to anticoagulant toxicities?
Swine
What are the clinical signs and lesions associated with anticoagulant toxicities?
Hemorrhage Green or blue-green feces CNS signs SQ hematomas Lameness Hypovolemic shock Abortions Sudden death
What is the clinical pathology with anticoagulant toxicity?
Prolongation of any clotting test
PT 1st because of factor 7
By 48 hours, PTT is elevated
What is the treatment for rodenticide toxicity when there are no clinical signs?
Decontamination of GI tract: emesis or activated charcoal with cathartic
Vitamin K PO or monito PT
What is the treatment for rodenticide toxicity when there are clinical signs?
Correct low PCV, hypovolemia, provide clotting factors
Vitamin K
What is the duration of treatment with warfarin toxicosis?
10-14 days
What is the duration of treatment with bromadiolone toxicosis?
21 days
What is the duration of treatment with diphacinone, brodifacoum toxicosis?
30 days
What are contraindicated drugs during treatment of anticoagulant toxicosis?
NSAIDs
What are sources of coumarin anticoagulants?
Rodenticides
Moldy sweetclover poisoning
Coumadin
What is the toxic prinicple in Melilotus spp (moldy sweetclover)?
Coumarin glycosides converted to dicoumarol by molds
What is the MOA of Melilotus spp (moldy sweetclover)?
Competitively inhibits the epoxide reductase that activates vitamin K
What species is affected by Melilotus spp (moldy sweetclover)?
Livestock, most often cattle
What time of year does Melilotus spp (moldy sweetclover) toxicosis occur?
Winter when fed hay
What are the signs of Melilotus spp (moldy sweetclover) poisoning?
Blood loss Hematomas Anemia Epistaxis Hemorrhagic diarrhea Abortion
What is the clinical pathology with Melilotus spp (moldy sweetclover)?
Prolonged PT and PTT
Decreased PCV and total protein
What are the lesions with Melilotus spp (moldy sweetclover)?
Extensive hemorrhages
What is the treatment for Melilotus spp (moldy sweetclover) toxicosis?
Discontinue feeding affected hay
Whole blood transfusions
Vitamine K
What is Pteridium aquilinum?
Bracken fern
What is the toxic principle in Pteridium aquilinum (Bracken fern)?
Ptaquiloside in cattle
Thiaminase in horses
What is the MOA of Pteridium aquilinum (Bracken fern)?
Hematopoietic depression in cattle
Thiamine in GI tract in horses
What is the toxic part of Pteridium aquilinum (Bracken fern)?
All, especially young plants and rhizomes
What species are affected by Pteridium aquilinum (Bracken fern)?
Cattle, horses
Rarely swine
What is the time frame of Pteridium aquilinum (Bracken fern) toxicosis?
1-2 months of consumption
What is the time of year for Pteridium aquilinum (Bracken fern) toxicosis?
Late summer, early fall
What are the signs of Pteridium aquilinum (Bracken fern) toxicosis?
Emaciation, lethargy Incoordination (bracken staggers) Tremors Bradycardia Convulsions Death 2-10 days after signs
What are the lesions with Pteridium aquilinum (Bracken fern) toxicosis in cattle?
Generalized hemorrhage, anemia, aplastic marrow
Urinary bladder: hyperplasia –> neoplasms
What are the lesions with Pteridium aquilinum (Bracken fern) toxicosis in horses?
Enteritis
Pericardial hemorrhages
Polioencephalomalacia
What is the method of diagnosing toxicosis from Pteridium aquilinum (Bracken fern) in horses?
Assay for thiamine in whole blood
What is the treatment for Pteridium aquilinum (Bracken fern) toxicosis in cattle?
Blood transfusions
Antibiotics
D,I-batyl alcohol
What is the treatment for Pteridium aquilinum (Bracken fern) toxicosis in horses?
Thiamine HCl for days to weeks
Supportive
What is Acer rubrum?
Red maple
What is the toxic principle of Acer rubrum (red maple)?
Gallic and tannic acids
What is the MOA of Acer rubrum (red maple)?
Hemoglobin oxidant
What is the toxic part of Acer rubrum (red maple)?
Leaves, especially wilted and dried
What are the species affected by Acer rubrum (red maple)?
Horses
What is the time frame of Acer rubrum (red maple) toxicosis?
4-5 days after consumption
What is the time of year Acer rubrum (red maple) toxicosis occurs?
Mostly July to October
What is the toxic dose of Acer rubrum (red maple)?
> 1.5 g/kg BW dried red maple leaves
What is the sign of acute 1st phase of Acer rubrum (red maple) toxicosis?
Methemeglobinemia
What is the sign of acute 2nd phase of Acer rubrum (red maple) toxicosis?
Heinz body anemia
Icterus* (extravascular)
Hemoglobinemia, hemoglobinuria (intravascular)
What is the lab diagnosis of Acer rubrum (red maple) toxicosis?
Methemoglobinemia without anemia initially
Heinz bodies
Low PCV
Hyperbilirubinemia
What are the lesions with Acer rubrum (red maple) toxicosis?
Renal: tubular nephrosis, Hb casts in kidney (if intravascular)
Spleen: erytyrophagocytosis, hemosiderosis (extravascular)
What is the treatment of Acer rubrum (red maple) toxicosis?
Ascorbic acid to reduce MetHb to Hb α-tocopherol less effective Supportive Whole blood transfusions Fluids, diuresis to reduce Hb nephrosis
What is the prevention of Acer rubrum (red maple) toxicosis?
Don’t plant near horse barns
Remove downed limbs or trees immediately after storms
Prevent accumulation of leaves in pastures or hay
What is Allium?
Onions, garlic
What is the toxic principle of Allium (onions, garlic)?
Large variety of sulfur-containing oxidants including N-propyl disulfide
Raw, dried, cooked garlic and onions
What is the MOA of Allium (onions, garlic)?
Hemolysis of RBCs occurs when oxidative injury from Allium-derived SCOs exceeds erythrocyte antioxidant capabilities
Heinz bodies with hemolysis, secondary to oxidant effect
What is the toxic part of Allium (onions, garlic)?
Bulb
What are the species affected by Allium (onions, garlic)?
All. Horses and cattle are the most susceptible LA
Dogs, cats most susceptible SA
What is the time frame of Allium (onions, garlic) toxicosis?
Dose dependent
What are the signs of Allium (onions, garlic) toxicosis?
Transient gastroenteritis
Acute hemolytic crisis: cyanosis, low PCV, Heinz bodies, hyperbilirubinemia, HBemia/Hburia, icterus
What is the treatment of Allium (onions, garlic) toxicosis?
Supportive therapy: O2 and/or blood replacement
Cats: no methylene blue –> Hz body anemia and MetHb
What can cause acute bovine pulmonary emphysema (ABPE) or acute respiratory disease syndrome (ARDS?
Ruminants and horses: 4-ipomeanol
Perilla frutescens
Ruminants only: lush forage, Brassica sp, 3-methylindole
What is the toxic principle of perilla mint?
Perilla ketone (3-substituted furan)
What is the MOA of perilla mint?
Mixed function oxidases bioactivate
What is the most toxic part of perilla mint?
Flowers and seeds
What is the toxic principle of lush forage?
3-MI
What is the toxic principle of moldy sweet potato?
4-ipomeanol
What is the MOA for ABPE/ARDS?
Free radicals, lipid peroxidation
What are the signs of ABPE/ARDS?
Dyspnea, cyanosis, disorientation, bellowing, recumbency, death
What are the lesions with ABPE/ARDS?
Pulmonary emphysema
Type I cells are absent or necrotic
Type II cells replace type I cells causing a glandular appearance
What is the treatment of ABPE/ARDS?
Minimize stress
Supportive
What is the prevention of ABPE/ARDS?
Avoid abrupt dietary change
Limit grazing of Perilla mint during flowering
Limit intake of moldy sweet potatoes
Ionophores and tetracyclines to inhibit growth of Gm+ ruminal bacteria that convert tryptophan to indole
What is the MOA of urea toxicosis?
NH3 absorbed in bloodstream –> toxic to enzymes in TCA cycle
What does causes toxicity with NPN?
0.3-1.5 g/kg bw
What factors influence toxicity of NPN?
Dose Adaptation Acute poisoning pH of rumen High energy feeds needed for proper utilization of urea Death from lactic acidosis or hyperkalemic heart failure Maturity of animals Hydration Hepatic insufficiency Lack of natural protein Fasting Plants with ureases enhance hydrolysis of urea
What are the signs of urea toxicosis?
Acute onset: 0.5-6 hours
Salivation, abdominal pain
Muscle tremors, hyperthermia, convulsions
Recumbency, bloat, regurgitation of rumen contents
What is the lab diagnosis of urea toxicosis?
Metabolic acidosis
Blood ammonia: 1-4 mg/dl
Rumen ammonia: >80 mg/dl
Rumen pH >7.5
What is the treatment of urea toxicosis?
Ruminal infusion of cold water and acetic acid, 6 hour intervals to 48 hours
Treatment for metabolic acidosis
Rumenotomy to remove contaminated feed
What are examples of andromedotoxins?
Rhododendron spp (Rhododendron, Azaleas) Kalmia (Laurel, lambkill, calfkill) Pieris japonica (Japanese peris)
What is the toxic principle of andromedotoxins?
Andromedotoxins (diterpenoids)
What is the MOA of andromedotoxins?
Toxins bind to and keeps Na channels open
Prlonged depolarization and excitation
What is the toxic part of andromedotoxins?
All, especially leaves and flower nectar
What species are affected by andromedotoxins?
All, cattle, sheep, goats, horses
What is the time frame of andromedotoxins?
Acute, usually hours
What is the toxic dose of andromedotoxins?
1-3% BW in cattle experimentally
What are the signs of andromedotoxins?
Salivation, burning sensation in mouth. emesis, diarrhea
Bradycardia, hypotension, AV block
What is the treatment of andromedotoxins?
Emesis Supportive therapy: fluid therapy Atropine for bradycardia Isoproterenol for heart block
What are Taxus spp. and Cephalotaxus spp?
Yew
What is the toxic principle of Taxus spp. and Cephalotaxus spp (Yew)?
Taxine alkaloids A and B
What is the MOA of Taxus spp. and Cephalotaxus spp (Yew)?
Inhibits depolarization in the heart
What is the toxic part of Taxus spp. and Cephalotaxus spp (Yew)?
All except ripe fruit
What species are affected by Taxus spp. and Cephalotaxus spp (Yew)?
All livestock, dogs, wild animals, humans
Monogastrics are more sensitive
What is the time frame for Taxus spp. toxicosis?
Acute, sudden death common
What is the toxic dose of Taxus spp?
6-8 oz
What are the signs of Taxus spp. toxicosis?
Trembling, muscle weakness, dyspnea, collapse
Arrythmiam, bradycardia, heart block
What are the lesions associated with Taxus spp?
None
Where is Taxus spp. consistently found?
GI tract
What is the treatment for Taxus spp?
Remove from source Respiration Emesis Gastric lavage Activated charcoal and salin cathartic Atropine early Maintain body fluid and electrolyte balance