Metaldehyde

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Metaldehyde and acetaldehyde are rodenticide toxins used to control snails and slugs[1].

These baits are often indiscriminately eaten off the ground or obtained from storage areas, often despite a variety of preventive measures[2].

This poison primarily induces parasympathomimetic symptoms including ptyalism, muscle tremors, ataxia, vomiting and diarrhea, which can be confused with organophosphate toxicity. Other symptoms include hyperthermia, tachycardia and agitation.

A small number of patients may develop acute renal injury and hepatitis[3], characterized by hyperkalemia and hyperbilirubinemia[4].

Diagnosis is usually based on history of exposure and clinical symptoms. Laboratory examination of vomitus is usually definitive.

Treatment usually involves induction of emesis with apomorphine and in severe cases, intravenous fluid therapy with lactated Ringer's solution and induction of general anesthesia with thiopentone and maintenance on halothane, allowing for gastric lavage and administration of activated charcoal.

Muscle tremors and hyperesthesia in mildly affected dogs can be controlled with diazepam.

The prognosis depends on severity of clinical signs and their duration, but mildly affected dogs usually recover within 24 hours.

References

  1. Booze TF & Oehme FW (1986) An investigation of metaldehyde and acetaldehyde toxicities in dogs. Fundam Appl Toxicol 6(3):440-446
  2. Studdert VP (1985) Epidemiological features of snail and slug bait poisoning in dogs and cats. Aust Vet J 62(8):269-271
  3. Bates NS et al (2012) Suspected metaldehyde slug bait poisoning in dogs: a retrospective analysis of cases reported to the Veterinary Poisons Information Service. Vet Rec 171(13):324
  4. Yas-Natan E et al (2007) Clinical, neurological and clinicopathological signs, treatment and outcome of metaldehyde intoxication in 18 dogs. J Small Anim Pract 48(8):438-443