Toxicology 2018 Flashcards
A 65 lb mixed breed dog was presented to the clinic looking totally normal. Three weeks prior to presentation, the field adjacent to the client’s house was treated with Omega Gopher Grain Bait - active ingredient is strychnine, at a concentration of .5%. Approximately 30 minutes prior to presentation, the dog was seen ingesting a dead gopher after roaming around in the treated field. The owner is concerned about the dog potentially succumbing to either a primary or secondary strychnine poisoning.
There is a risk of seeing a secondary poisoning with strychnine, so Dr. Munck did induce vomiting with a specific drug, given IV, that is over 90% effective in inducing emesis in dogs: _________________.
The patient did vomit up the rodent, and Dr. Munck then administered maropitant, followed by one dose of activated charcoal and sorbitol.
Describe the rationale for giving AC:
Describe the rationale for giving sorbitol:
How specifically does the electrolyte imbalance hypernatremia occur?
Apomorphine
AC binds to compounds to help reduce absorption and is osmotically active
Sorbitol is a cathartic; it helps draw water into the GI tract to decrease GI transit time and reduce absorption
Activated charcoal and sorbitol are both osmotically active, drawing water into the GIT, which can cause dehydration and hypernatremia relative to this dehydration.
Describe the mechanism of action of strychnine AND describe how this MOA is directly responsible for the observed clinical signs in poisoned animals.
Strychnine inhibits the action of glycine in the spinal cord and medulla. Because glycine is an inhibitory neurotransmitter, this results in reflex muscle contraction. The extensor muscles are stronger than the flexor muscles, resulting in extensor rigidity - the primary clinical sign of strychnine poisoning.
Rachel was recently on her cardiology rotation in the VTH when she was presented with a 13-year-old MN Rat Terrier dog named PT for the primary complaint of lethargy and change of skin color on his abdomen. History: Three days ago PT was at the owner’s lake house at Hepburn State park when he fell into the lake. Not knowing if he could swim, the owner grabbed PT and tossed him 5-10 feet onto the rocky shore. The owner later noticed a change in color of the skin on PT’s abdomen. PT has also been having some shifting leg lameness and today has been intermittently non-weight-bearing lame on his left pelvic limb. All else is going fine with PT - he is taking all his medications for his mitral valve endocarditis, collapsing trachea, and bronchitis. Hie is eating and drinking well, no vomiting or diarrhea, and he is urinating normally.
Assess the vitals:
T: 102.4 F
P: 100 beats/minute
R: 36 breaths/minute
When you see bleeding, you should always be thinking in the back of your mind - test clotting times! The prothrombin time (PT) and partial thromboplastin time (PTT) were both prolonged! ALL of the following would be considered reasonable differentials in this case EXCEPT (choose ONE BEST answer):
- Anticoagulant rodenticide
- Liver disease/failure
- Renal disease/failure
- Disseminated intravascular coagulation
T: 102.4 F (NORMAL)
P: 100 beats/minute (NORMAL)
R: 36 breaths/minute (HIGH)
Renal disease/failure
A 118 lb Rottweiler ate an entire 42 oz package of a bromethalin-containing bait, .01% bromethalin. ALL of the following are true regarding bromethalin exposures in dogs EXCEPT (choose ONE BEST answer):
- Bromethalin is a rodenticide that has a long half-life in dogs due to enterohepatic recirculation.
- Bromethalin replaces acetyl CoA in the Kreb’s cycle and combines with citrate, effectively inhibiting the aconitase enzyme that shuts down the cycle, thereby preventing the production of ATP.
- Dogs exposed to < LD50 dose experience a paralytic form of the disease, characterized by lethargy, ataxia, and hind limb paresis to paralysis.
- Dogs exposed to > LD50 dose experience the convulsant form of the disease, characterized by muscle tremors and tonic/clinic seizure activity.
- Treatment options for asymptomatic patients like the Rottweiler above include aggressive decontamination procedures, like emesis and multiple doses of activated charcoal (3-4 doses within a 24 hour period).
Bromethalin replaces acetyl CoA in the Kreb’s cycle and combines with citrate, effectively inhibiting the aconitase enzyme that shuts down the cycle, thereby preventing the production of ATP.
Daily administration of lawn care products are given orally to dogs to change the urine pH in attempts to prevent their urine from harming the grass. Dogs exposed to too much of these products can display vomiting, ataxia, transient hind limb paresis, and abnormal postures. The active ingredient in these products that is associated with these clinical problems is: ____________.
DL methionine
A rDVM was presented on emergency in the early evening with five parrots from the same household, all showing acute respiratory distress (open mouth breathing) and extreme lethargy (unable to perch or stay upright). One of the parrots was also displaying seizure-like activity. History revealed the owner had just received a new set of pots and pans for her birthday and was cooking with them in the kitchen, adjacent to the living room where the birds were kept.
Name the specific compound that is present on some nonstick cookware, that when heated to high temperatures, can release fumes and particulates that are extreme respiratory toxins to birds.
Name at least TWO other items commonly coated with this compound that can lead to death in birds when overheated.
PTFE (Polytetrafluoroethylene)
Heat lamps, clothes iron
Name the mycotoxin that can be found in grains that acts as a weak estrogen.
Zearalenone
Name the mycotoxin that is a potent salivary gland M3 agonist that causes excessive salivation in livestock.
Name the feed type where you are most likely to find the mold that produces this mycotoxin.
Slaframine
Alflalfa
ALL of the following are TRUE regarding paraquat EXCEPT (choose ONE BEST answer):
- Paraquat is a popular herbicide used on many different types of crops, and acts as a desiccant.
- Most exposures are oral, and the majority of what gets absorbed is excreted via urine unchanged.
- Paraquat will accumulate in the lung where it has a long half-life (24 hours) and the pathologic changes in the lung are due to the production of free radicals.
- The initial clinical syndrome in acute intoxications include gastrointestinal and pulmonary signs, and if the animal survives, the later clinical syndrome (5-7 days) include pulmonary and hepatic signs.
- The initial clinical syndrome in acute intoxications include gastrointestinal and pulmonary signs, and if the animal survives, the later clinical syndrome (5-7 days) include pulmonary and hepatic signs.
FALSE - pulmonary and RENAL signs
Name the molluscicide that can cause muscle tremors and enhanced sensitivity to external stimuli in affected animals.
Metaldehyde
In birds, the BEST chelator to use, IM, to remove lead is:
CaEDTA
Postmortem, name the TWO BEST tissues to submit to toxicology to quantitate lead levels.
Liver and kidney
What is the most common source of lead for eagles?
Grazing carcasses killed with lead shot and ingesting the lead shot.
Name the best chelator for removing lead in dogs.
Succimer
It is more common to see lead poisoning in cattle - BLIND COW, THINK LEAD - name the most common source.
In cattle, postmortem, if you are suspicious of lead poisoning what SPECIFIC portion of the GIT should you remove and take back to your clinic to radiograph?
Batteries
Reticulum
T/F: Young animals are uniquely sensitive to lead intoxication due to enhanced uptake from the GI tract (10% uptake in adults compared to 50% uptake in juveniles).
TRUE
List FIVE objective assessments that are on the ECC Admission Panel that are useful to determine hydration/tissue perfusion status from a blood/serum sample.
PCV TP BUN Creatinine Lactate
