ICVA - International Council for Veterinary Assessment Feline Pharmacology and Toxicology Questions and Answers 1 — Questions and Answers
Question 1: A cat owner accidentally applies a flea and tick product containing a high concentration of permethrin, intended for a large dog, to their 5-kg cat. Within hours, the cat presents with severe muscle tremors, hypersalivation, and ataxia. Which of the following is the most critical initial step in managing this toxicity after stabilizing the patient's tremors?
- Administer intravenous lipid emulsion (ILE) therapy.
- Induce emesis immediately with apomorphine.
- Bathe the cat with a mild dish soap and lukewarm water. (Correct answer)
- Administer a dose of N-acetylcysteine intravenously.
Correct answer: Bathe the cat with a mild dish soap and lukewarm water.
Permethrin is a topically absorbed neurotoxin, and dermal decontamination is crucial to prevent further absorption. After controlling life-threatening signs like seizures or severe tremors, washing the cat with a mild dish soap (which is effective at removing the oily base of the product) and lukewarm water is a critical step. While intravenous lipid emulsion therapy is an important treatment for permethrin toxicosis, it is used to bind the toxin within the bloodstream and is typically initiated after decontamination. Inducing emesis is not indicated as the toxin was applied topically, not ingested. N-acetylcysteine is the antidote for acetaminophen toxicity, not permethrin.
Question 2: A 4-year-old domestic shorthair cat presents with a 12-hour history of vomiting, lethargy, and anorexia. On physical examination, the cat is dehydrated, and palpation of the abdomen reveals enlarged, painful kidneys. The owner mentions receiving a bouquet of flowers yesterday. Ingestion of which of the following plants is most likely responsible for these clinical signs?
- Poinsettia (Euphorbia pulcherrima)
- Peace Lily (Spathiphyllum spp.)
- Easter Lily (Lilium longiflorum) (Correct answer)
- Aloe Vera (Aloe barbadensis miller)
Correct answer: Easter Lily (Lilium longiflorum)
Ingestion of any part of a true lily, such as the Easter Lily (Lilium species) or Daylily (Hemerocallis species), is extremely toxic to cats and causes severe, acute renal failure. The clinical signs of vomiting, lethargy, anorexia, and enlarged, painful kidneys are classic for lily toxicosis. While Peace Lilies and Aloe Vera can cause gastrointestinal upset, and Poinsettias cause mild irritation, none of them cause acute kidney failure.
Question 3: Which physiological characteristic is the primary reason for the increased sensitivity of cats to drugs like acetaminophen and certain NSAIDs?
- Higher glomerular filtration rate
- Deficiency in hepatic glucuronidation pathways (Correct answer)
- Increased plasma protein binding of drugs
- Rapid acetylation of xenobiotics
Correct answer: Deficiency in hepatic glucuronidation pathways
Cats have a relative deficiency in the enzyme UDP-glucuronosyltransferase (UGT), which is crucial for the glucuronidation pathway of drug metabolism in the liver. This metabolic limitation leads to slower clearance and accumulation of toxic metabolites from drugs like acetaminophen and certain NSAIDs, making cats highly susceptible to their toxic effects.
Question 4: A veterinarian is considering prescribing meloxicam for postoperative pain management in a 3-year-old cat following an ovariohysterectomy. According to FDA guidelines in the U.S., what is the approved administration protocol for meloxicam in cats?
- A single subcutaneous injection prior to surgery. (Correct answer)
- A three-day course of oral tablets.
- A low-dose daily oral liquid for up to one week.
- An initial injection followed by oral tablets for 5 days.
Correct answer: A single subcutaneous injection prior to surgery.
In the United States, the FDA has approved meloxicam for cats only as a one-time subcutaneous injection for the control of postoperative pain and inflammation associated with orthopedic surgery, ovariohysterectomy, and castration. Repeated use or the use of oral meloxicam in cats has been associated with acute renal failure and is not FDA-approved for long-term use.
Question 5: A client calls in a panic stating they just saw their cat lick some antifreeze (ethylene glycol) that had leaked from their car. What is the most severe and life-threatening consequence of ethylene glycol ingestion in cats if left untreated?
- Severe gastrointestinal ulceration
- Methemoglobinemia and Heinz body anemia
- Acute, irreversible renal failure (Correct answer)
- Central nervous system stimulation and seizures
Correct answer: Acute, irreversible renal failure
Ethylene glycol is metabolized in the liver to toxic metabolites, primarily glycolate and oxalate. Calcium oxalate crystals precipitate in the renal tubules, causing severe tubular necrosis and leading to acute, often irreversible, kidney failure. While initial signs can include CNS depression, the ultimate cause of death in untreated cases is typically renal failure.
Question 6: Which of the following best describes the primary toxic effect of acetaminophen in cats, distinguishing it from the toxicity seen in most other species?
- Severe hepatotoxicity leading to acute liver failure.
- Profound methemoglobinemia leading to impaired oxygen transport. (Correct answer)
- Cardiotoxicity resulting in arrhythmias and heart failure.
- Neurotoxicity causing seizures and central nervous system depression.
Correct answer: Profound methemoglobinemia leading to impaired oxygen transport.
Due to their deficiency in glucuronidation, cats metabolize acetaminophen through alternative pathways, leading to the formation of reactive metabolites that cause oxidative damage to red blood cells. This results in the formation of methemoglobin, which cannot carry oxygen, and Heinz bodies, leading to hemolytic anemia. The primary clinical manifestation is therefore severe methemoglobinemia, cyanosis, and dyspnea, which is different from the primary hepatotoxicity seen in humans and dogs.
ICVA - International Council for Veterinary Assessment Feline Pharmacology and Toxicology Questions and Answers 1
A cat owner accidentally applies a flea and tick product containing a high concentration of permethrin, intended for a large dog, to their 5-kg cat.
Within hours, the cat presents with severe muscle tremors, hypersalivation, and ataxia.
Which of the following is the most critical initial step in managing this toxicity after stabilizing the patient's tremors?