Acute Medullary Ischemic Infarctionin a Toy Poodle:MRI Findings and Clinical Recovery

A 13-year-old neutered male toy poodle was presented with acute onset of left-sided collapse followed by generalized seizure. Magnetic resonance imaging (MRI) revealed a focal lesion in the left medulla oblongata characterized by hyperintensity on T2-weighted and Fluid-Attenuated Inversion Recovery (FLAIR) sequences, absence of contrast enhancement, hyperintensity on diffusion-weighted imaging, and corresponding hypointensity on the apparent diffusion coefficient map, consistent with acute ischemic infarction. Cerebrospinal fluid (CSF) analysis was unremarkable, showing normal protein and cell counts without evidence of inflammation or neoplasia, thereby supporting an ischemic rather than inflammatory etiology. The patient was treated with an antiplatelet agent (clopidogrel), anticoagulant (rivaroxaban), vasodilator (pentoxifylline), and adjunctive supportive medications. Neurological deficits, including hemiparesis and decreased reflexes, gradually improved over the following weeks, with near-complete recovery was observed by 65 days post-onset. This case underscores the importance of diffusion MRI and CSF analysis for the differential diagnosis of ischemic stroke in dogs and highlights that acute medullary infarction may carry a positive prognosis when timely antithrombotic and supportive measures are instituted