A Case of Myasthenia gravis post covid vaccination with bilateral neurovascular conflict

Abstract

Myasthenia Gravis is an autoimmune postsynaptic neuromuscular junction disorder. The body produces auto antibodies against the postsynaptic nicotinic acetylcholine receptors. The disease is characterised by muscle weakness that fluctuates , worsening with exertion, and improving with rest. In about two thirds of the patients, the involvement of extrinsic ocular muscles presents as the initial symptom, usually progressing to involve other bulbar muscles and limb and respiratory musculature, resulting in generalised myasthenia gravis patients.1  The ocular symptoms include drooping of the upper lid, binocular horizontal diplopia, typically more in the evening and improving on rest. On examination, the patients have Ptosis and extraocular muscle limitation, that improve with sleep and ice pack test.

One important differential diagnosis of Myasthenia Gravis is Oculomotor Nerve Palsy. Third Cranial Nerve supplies the levator palpebrae superioris, and the four extraocular muscles (superior, medial, and inferior rectus and inferior oblique) and ciliary and sphincter pupillae. Signs include Ptosis, extraocular muscle limitation except for abduction and depression, and anisocoria with a sluggishly reacting pupil. One of the causes of the Oculomotor Nerve Palsy is an abnormal contact of artery or vein with the nerve, so called neurovascular conflict. A Neurovascular Conflict results in an active nerve dysfunction.

We present the case of a young adult male who presented in myaesthenic crisis following vaccination for COVID 19 infection with not so classical signs of ocular myaesthenia  but also had features of  bilateral neurovascular conflict on neuroimaging  .The etiological role of neurovascular conflict in causing third nerve compression was difficult to establish and could be a incidental finding . There are also no reported cases of precipitation of myasthenia following covid vaccination.