Canis ISSN: 2398-2942

Bromethalin poisoning

Contributor(s): Nicola Bates

Introduction

  • Rodenticide poison produced as grain-based bait or pellets.
  • Signs: neurological signs with seizures.
  • Diagnosis: signs and post-mortem demonstration of bromethalin or the metabolite desmethylbromethalin in tissues.
  • Treatment: symptomatic with repeat dose activated charcoal and possibly lipid infusion.
  • Prognosis: guarded and may need prolonged aftercare.

Pathogenesis

Etiology

  • Direct ingestion of bait/pellets.
  • Eating small vermin which have been poisoned.

Predisposing factors

  • Young age.

Pathophysiology

  • Both bromethalin and the active metabolite desmethylbromethalin uncouple oxidative phosphorylation.
  • There is inadequate ATP production by mitochondria and then decreased sodium/potassium ion channel pump activity.
  • Cells lose their osmotic control and retain sodium and swell with water resulting in cerebral edema and increased CSF pressure.
  • The oral LD50 in dogs has been reported as 3.65 mg/kg and 4.7 mg/kg.
  • In toxicity studies, dogs remained asymptomatic after 0.5 to 1.5 mg/kg (5-15 mg/kg of 0.01% bait).
  • In clinical cases signs have occurred with doses as low as 0.15 mg/kg with deaths from doses as low as 0.95-1.05 mg/kg.

Timecourse

  • At low doses signs can occur within 1-7 days at higher doses (approximately 5 mg/kg) signs can occur within 2-36 hours. 
  • At low doses signs can progress for 1-2 weeks.
  • At high doses death can occur within 4-63 hours.

Epidemiology

  • Cases are generally reported in North America and following changes in rodenticide regulations cases in companion animals are increasing.

Diagnosis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Prevention

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Tourdot R (2017) The decontamination dilemma: bromethalin ingestion. Today’s Vet Practice 7 (1) 95-99 VetMedResource.
  • Heggem-Perry B, McMichael M, O'Brien M, Moran C (2016) Intravenous lipid emulsion therapy for bromethalin toxicity in a dog. JAAHA 52 (4), 265-268 PubMed.
  • Bates M C, Roady P, Lehner A F, Buchweitz J P, Heggem-Perry B, Lezmi S (2015) Atypical bromethalin intoxication in a dog: pathologic features and identification of an isomeric breakdown product. BMC Vet Res 11, 244 PubMed.
  • Rubinstein I, Weinberg G (2014) Antidote for bromethalin poisoning. Can Vet J  55, 1185 PubMed.
  • Peterson M E (2013) Bromethalin. Top Companion Anim Med 28, 21-23 PubMed.
  • Dorman D C, Parker A J & Buck W B (1990) Bromethalin toxicosis in the dog. Part I: clinical effects. Part II: selected treatments for the toxic syndrome. JAAHA 26 (6), 589-594, 595-598 VetMedResource.

Other sources of information

  • Dorman D C (2006) Bromethalin. In: Small Animal Toxicology, 2nd edition. Peterson M E, Talcott P A (eds). St Louis, Missouri: Saunders Elsevier.

Organisation(s)


ADDED