A prospective study on clinical signs, management, outcomes, and delayed neurologic sequelae due to metaldehyde poisoning in 26 dogs

Background: Metaldehyde poisoning in dogs is well known and described issue. Several studies focused on the incidence, epidemiological features, and clinical and pathological findings associated with this intoxication. However, there are no prospective studies of metaldehyde poisoning and late-onset seizures. Aims: To prospectively describe clinical signs, therapeutic management, outcomes, and delayed-onset seizures due to metaldehyde poisoning in dogs. Methods: A 15-month prospective study on dogs with a diagnosis of metaldehyde poisoning, either via phone call to the animal poison control center or analysis at the toxicology laboratory in Lyon, France. Clinical signs, therapeutic management and outcomes, and the late onset of seizures were assessed for at least 3 years. Results: Twenty-six dogs were enrolled in the study. The most prevalent clinical signs were ataxia (18 dogs), convulsions (17), hypersalivation (15), and tremors (15). Treatment was symptomatic (e.g., activated charcoal, emetic therapy, and intravenous fluids) with anticonvulsant therapy (mainly diazepam). The overall survival rate was 81% (21/26 dogs). All dogs that received active charcoal (11/11) or emetic therapy (4/4) survived. Twelve of 17 dogs had convulsions and survived; 9 were followed up for at least 3 years after poisoning, and none had any other seizure episode or neurological sequelae. Conclusion: This prospective study describes clinical signs, therapeutic management and outcome of metaldehyde poisoning in dogs, and late-onset neurologic sequelae. None of the nine cases that were followed for 3 years developed neurological signs after metaldehyde poisoning. Therefore, long-term antiepileptic therapy is not indicated.