External ophthalmoparesis as part of generalised myasthenia gravis in a dog: are there more similarities to the human counterpart than originally thought?

Abstract

AbstractMyasthenia gravis in dogs is an autoimmune disease affecting the neuromuscular junction and resembling its human counterpart. Classification of the disease in humans includes an ocular and generalised form. Isolated ocular myasthenia gravis is confined to the extraocular muscles which most commonly results in ptosis, due to an impaired levator palpebrae superioris muscle responsible for elevating the upper eyelid, and diplopia (double vision) due to weakness of the extraocular bulbar muscles. Isolated ocular myasthenia gravis frequently becomes generalized over time or can present as part of generalised myasthenia gravis. Myasthenia gravis in dogs is classified by severity and distribution of clinical signs, as well as, serology and thymic status. However, it does not include the extraocular muscles. This is the first description of a case of ocular myasthenia gravis in a dog, progressing to generalised myasthenia gravis as seen in humans.