Ocular Myasthenia Gravis: A Current Overview

Abstract

Ocular myasthenia gravis (OMG) is a neuromuscular disease characterized by autoantibody production against postsynaptic proteins in the neuromuscular junction. The pathophysiological auto-immune mechanisms of myasthenia are diverse, and this is governed primarily by the type of autoantibody production. The diagnosis of OMG relies mainly on clinical assessment, the use of serological antibody assays for acetylcholine receptors (AchR), muscle-specific tyrosine kinase (MusK), and low-density lipoprotein 4 (LPR4). Other autoantibodies against post-synaptic proteins, such as cortactin and agrin, have been detected; however, their diagnostic value and pathogenic effect are not yet clearly defined. Clinical tests such as the ice test and electrophysiologic tests, particularly single-fiber electromyography, have a valuable role in diagnosis. The treatment of OMG is primarily through cholinesterase inhibitors (pyridostigmine), and steroids are frequently required in cases of ophthalmoplegia. Other immunosuppressive therapies include antimetabolites (azathioprine, mycophenolate mofetil, methotrexate) and biological agents such as B-cell depleting agents (Rituximab) and complement inhibitors (eculizumab). Evidence is scarce on the effect of immunosuppressive therapy on altering the natural course of OMG. Clinicians must be vigilant of a myasthenic syndrome in patients using immune-check inhibitors. Reliable and consistent biomarkers are required to assess disease severity and response to therapy to optimize the management of OMG. The purpose of this review is to summarize the current trends and the latest developments in diagnosing and treating OMG.

Double seronegative myasthenia gravis but double positive - A case of LRP4/Agrin antibody positive myasthenia gravis

“…2 Combined agrin and LRP4 antibody positive MG patients have more severe symptoms than isolated LRP4 MG. LPR4 antibodies have also been reported in disorders such as amyotrophic lateral sclerosis, polymyositis, multiple sclerosis and neuromyelitis optica. 5 Up to 50% of triple seronegative MG patients (i.e., AChR Ab-, MuSK-, LRP4 -) have serum antibodies against agrin, which represents 2-3% of all MG patients. 6 Agrin antibody positive MG usually occur in middle-aged or elderly men.…”