Bilateral idiopathic oculomotor neuropathy in a dog

Abstract A 2‐year‐5‐month‐old, female, entire golden retriever presented with a 3‐day history of a per‐acute onset, non‐progressive bilateral mydriasis. On neurological examination, the patient had a bilateral internal ophthalmoplegia, with no apparent ophthalmological cause noted on ophthalmic assessment. Both pupils constricted following the topical administration of 0.1% pilocarpine solution. The patient was neurolocalised to the parasympathetic portion of both oculomotor nerves. A diagnosis of bilateral idiopathic oculomotor neuropathy was reached once further investigations helped exclude other possible differential diagnoses. This is the first reported case of a bilateral idiopathic oculomotor neuropathy in a dog. At the 8‐week follow‐up, the patient's bilateral internal ophthalmoplegia remained static, with no concurrent abnormalities noted on exam. Furthermore, following a telephone consultation, the patient's clinical signs remained static 19 months after initial presentation. Despite the static bilateral internal ophthalmoplegia, the patient was perceived to have had a good quality of life.