Feline toxicology

Feline toxicology

1. Permethrin

   • Insecticide used in dog spot-on flea treatments
   • Very potent
   • Grooming of a dog can cause toxicity
   • Acts as a neurotoxin: binds and blocks open sodium channels on the surface of nerve cells
   • Disrupts normal nerve function: muscle tremors, twitching and seizures, pyrexia, hypersalivation, dilated pupils
   • Signs occur within a few hours
   • Prognosis: guarded, high mortality rates, severe or fatal outcomes are common
   • Treatment: intensive/prolonged, supportive; IVFT, temperature control. Thoroughly wash with lukewarm water and milk shampoo to stop further absorption. Seizure management; benzodiazepines, barbiturates or sedation/GA to allow the muscles to relax.

2. Ethylene glycol

   • Found in antifreeze and car radiators/brake/transmissions fluid
   • Either drunk directly as is sweet tasing or groomed off contaminated fur.
   • Prognosis is grave and unpredictable
   • Toxic metabolites cause metabolic acidosis and renal tubular damage = ARF
   • Acidic and oxalate by-products = calcium oxalate crystals, crystalluria, hypocalcaemia.
   • Initial signs within 12 hours: vomiting, ataxia, depression, incoordination
   • After 24 hours: markes renal failure; oliguria or anuria, vomiting, hyperkalaemia, bradycardia, ECG abnormalities
   • Within 24 hours: renal damage = ARF
   • Diagnosis: clinical signs, renal parameters, urinalysis; isotenuria, calcium oxalate crystals. Blood levels can be assessed but take a while to recieve the results.
   • Treatment: if ingested within 12 hours: gastric decontamination; induce emesis or gastric lavage. Ehtanol (20% medicinal or plain vodka) can be given as a CRI of 1.25ml/hour for up to 72 hours to inhibit metabolism. Treatment after the first 12 hours is ineffective. Supportive care: 0.9% saline, constant monitoring, monitor urine output, thoracic auscultation to prevent fluid overload, diuretics to cotrect anuria but not until fluid deficits have been corrected. ECG abnormalities; spiked T waves: IV calcium gluconate. Peritoneal dialysis: benefts may not outweigh complications.
   • Peak plasma concentrations within 2-3hrs
   • Halflife = 3hrs

3. Lilies

   • Highly toxic
   • Entire plant is dangerous
   • Ingestion of less than one leaf can result in renal failure
   • Toxic effects occur from grooming contaminated fur
   • Clinical signs; apparant within a few hours; vomiting, depression, anorexia, GI irritation, hypersalivation, lethargy.
   • Treatment: decontamination of fur through washing, IVFT; twice maintenance for 48 hours, 0.9% saline or Hartmann's, monitor for signs of renal failure, prevent contact, monitor hydration status, prevent fluid overload, monitor bodyweight and central venous pressure, haemodialysis or peritoneal dialysis are successfl but rarely available. Furosemide or mannitol are not effective
   • Prognosis: guarded without treatment, can have permanent renal damage
     • Renal failure due to necrosis of renal tubular epithelial cells, basement membrane stays attached to prompt/aggressive treatment can result in cell regeneration.
   • From 24-72 hours: renal function deteriorates, elevated urea, creatinine, phosphorous, potassium,
   • Tubular necrosis with haematuria, proteinuria, glucosuria, isotenuria, squamous and epithelial cells and casts, PUPD, enlarged kidneys, convulsions, vomiting can start again at 36-48 hours due to uraemia.
   • Death occurs after 3-7 days
   • Treatment more than 18 hours after ingestion = poor outcome, high mortality