Phenotypic characterization of paroxysmal dyskinesia in Maltese dogs

Abstract

Background: Paroxysmal dyskinesias (PDs) are a group of central nervous system diseases characterized by episodes of abnormal involuntary hyperkinetic movement without altered consciousness that increasingly have been recognized in dogs. Objectives: To present the phenotypical characterization, treatment, and outcome of a PD observed in Maltese dogs. Animals: Client-owned Maltese dogs (n = 19) with presumed diagnosis of PD. Methods: Data were collected retrospectively from medical records (2014-2019), and supporting information was added prospectively by using a questionnaire directed to the owners of the affected dogs. Results: The episodes were characterized mainly by sudden dystonia of ≥1 limbs and generalized body tremors with preserved consciousness. The mean age of clinical onset was 5.4 years. Episode frequency varied widely both among and within individuals. Median episode duration was 4.5 minutes. Most episodes were stress- or exercise-induced. Acetazolamide was administered to 6 dogs, and 4 dogs experienced a decrease in episode frequency. In 7 dogs that received a gluten-free diet, 6 dogs became episode-free. In 4 dogs, the episodes stopped spontaneously and in 2 dogs no medication or specific diet was given and the episodes continued at the same frequency. Conclusions and Clinical Importance: Given the breed predisposition and regional distribution of the disease, additional research should focus on elucidating the underlying genetic cause doing so might advance both our understanding of the pathophysiology and treatment of this disease, not only in dogs, but also in humans. Regardless of the treatment protocol selected, prognosis appears fair to good.