Rodenticides Flashcards
source of exposure of anticoagulant rodenticides
ingestion of baits or eating contaminated feed;
malicious poisoning;
secondary toxicosis
MoA: Anticoagulant rodenticides
inhibit vitamin K epoxide reductase → reduction of coag factors II, VII, IX, XII (1972)
Clinical signs associated with anticoagulant rodenticides
onset in 1-5 days
signs of hemorrhage (vary on site of bleeding)- hematuria, bleeding from venipuncture sites, hematomas,
weakness, shock, tachypnea/dyspnea, anorexia, lethargy, abortion in cattle
Dx of anticoagulant rodenticides
Chemical analysis: blood (preferred), serum or plasma;
prolonged coag factors, anemia, thrombocytopenia, hypoproteinemia, radiographs (signs of hemorrhage)
treatment of anticoagulant rodenticides
vitamin K1 (K3 not effective - side effects) PO - don’t give IV→ anaphylaxis!!
Coag factors (FFP, cryoprecipitate)
DDx of anticoagulant rodenticides
spoiled sweet clover (cattle, horses)
vitamin K deficiency (swine, poultry)
DIC, liver disease, thrombocytopenia
T/F 1st generation anticoagulant rodenticides like Warfrin are effective after one dose and hava a long half life
False
2nd generations - more acutely toxic
1st generations - most toxic when ingested daily over 1 week
exposure: cholecalciferol
ingestion of rodenticides, relay (secondary) toxicosis, large doses of vit. D (feed additives, multivitamins, lotions), plants with vit. D analogs, psoriasis medication
MoA: cholecaliferol
causes hypercalcemia and hyperphosphatemia, can lead to mineralization of soft tissues
Clinical Signs: cholecaliferol
nonspecific (depends on tissues affected), anorexia, V+ (+/- blood), abdominal pain, constipation (+/- melena) dehydration, shock, PU/PD (hyposthenuria), arrhythmias, hypertension, depression, weakness, muscle twitching, seizures, coma, death
Dx cholecalciferol
history and clinical signs, lab findings, rads - mineralization of soft tissues
treatment of cholecalciferol
decontamination- emesis, activated charcoal (repeated doses), restrict therapy, supportive care
Treat the hypercalcemia - saline diuresis, furosemide, glucocorticoids, bisphosphonates
lab results: cholecaliferol
hypercalcemia, hyperphosphatemia, elevated calcidiol and calcitriol, decreased PTH, azotemia, proteinuria, glucosuria
DDx for cholecaliferal
DRAGONSHIT
exposure: bromethalin
ingestion of bait, secondary (relay) toxicosis - not reported but possible
MoA: bromethalin
uncoupling of oxidative phosphorylation, lack adequate ATP, insufficient energy for Na/K pumps
Brain and spinal cord: main targets (rely heavily on ox phos), ion pump dysfunction→ fluid imbalance, edema, increased pressure
clinical signs: bromethalin
may be acute or delayed
Acute-less common; CNS excitatory signs - muscle tremors, hyperthermia, hyperexcitability, running fits, generalized seizures
Subacute- more common; progressive, hind-limb ataxia, proprioceptive defects and paresis; can progress to paralysis, loss of deep pain, patellar hyperreflexia, UMN bladder, CNS depression, V+, anorexia, dementia, positional nystagmus, Schiff-sherrington, seizures, death due to resp. Failure
DDx: bromethalin
neurotoxins - strychnine, metaldehyde
trauma, neoplasia, encephalitis
treatment: bromethalin
no specific antidote,
decontamination - emesis, activated charcoal with sorbitol (cathartics) - avoid Mg cathartics (CNS depressive) repeated dosing q 4-8hrs x 2-4 days;
supportive/symptomatic care - Mannitol (cerebral edema), diazepam/phenobarb (seizures and tremors), nutritional support
bromethalin is considered a
General Use Pesticide (GUP)
MoA strychnine
block postsynaptic effect of glycine in the spinal cord
clinical signs: strychnine
rapid onset and rapid death
Early signs: apprehension, panting, nausea/V+, mydriasis, stiffness, muscle twitching, hyperthermia
Progresses to: tonic seizures (excitable by external stimuli) and opisthotonos, “sardonic grin” death from resp. failure
treatment of strychnine
decontamination - emesis, gastric lavage (bicarb and antacids in it), activated charcoal (repeated doses);
supportive care - fluids, O2, keep in quiet place and avoid stimuli, diazepam/methocarbamol (tremors) treat seizures;
may need to be sedated 24-72 hours
T/F strychnine and bromethalin and GUPs
False
strychnine is a “Restricted Use Pesticide” (RUP)
what should be avoided with strychnine
opioids, phenothiazines, neuromuscular blockers, and dissociative anesthetics
