Immunosuppressive treatment of ocular myasthenia gravis

Association of immunosuppression treatment with generalization among patients with ocular myasthenia gravis: a propensity score analysis

BACKGROUND

To analyze disease generalization in patients with ocular myasthenia gravis (OMG) treated with immunosuppression compared with patients without immunosuppression treatment.

METHODS

In this retrospective cohort study, we analyzed data from patients with OMG at seven medical centers in China from January 1, 2015 to May 1, 2019 and compared disease generalization in patients (treated with immunosuppression vs. not treated) within 2 years of disease onset using raw and inverse probability of treatment weighting (IPTW) analyses.

RESULTS

In the study population of 813 patients with OMG, 425 (52.3%) with immunosuppression had a mean (SD) onset age of 50.0 (15.1) years, and 188 (44.2%) were women. The remaining 388 (47.7%) patients were not immunosuppressed (mean age, 48.4 [15.0] years; 185 [47.7%] women). Disease generalization developed in 122 (31.4%) and 37 (8.7%) patients in the non-immunosuppression and immunosuppression groups, respectively. Relative to non-immunosuppression, immunosuppression was associated with a lower risk of generalization in a multivariable-adjusted Cox model (hazard ratio [HR], 0.27; 95% confidence interval [CI], 0.18-0.40; P<0.001) and IPTW-weighted Cox model (HR, 0.28; 95% CI, 0.19-0.42; P<0.001). In sensitivity analyses, longer duration of immunosuppression was associated with a lower risk of generalization (HR, 0.90 for every one-month increase; 95% CI, 0.87-0.92; P<0.001; IPTW-adjusted). Combination therapy with steroids and non-steroidal immunosuppressants showed superior efficacy in reducing the risk of generalization (HR, 0.14; 95% CI, 0.07-0.26; P<0.001).

CONCLUSIONS

Immunosuppression significantly reduced the 2-year risk of generalization in patients with OMG.

Fc-Receptor Targeted Therapies for the Treatment of Myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disease in which immunoglobulin G (IgG) antibodies (Abs) bind to acetylcholine receptors (AChR) or to functionally related molecules in the postsynaptic membrane at the neuromuscular junction. IgG crystallizable fragment (Fc)-mediated effector functions, such as antibody-dependent complement deposition, contribute to disease development and progression. Despite progress in understanding Ab-mediated disease mechanisms, immunotherapy of MG remained rather unspecific with corticosteroids and maintenance with immunosuppressants as first choice drugs for most patients. More specific therapeutic IgG Fc-based platforms that reduce serum half-life or effector functions of pathogenic MG-related Abs are currently being developed, tested in clinical trials or have recently been successfully translated into the clinic. In this review, we illustrate mechanisms of action and clinical efficacies of emerging Fc-mediated therapeutics such as neonatal Fc receptor (FcRn)-targeting agents. Furthermore, we evaluate prospects of therapies targeting classical Fc receptors that have shown promising therapeutic efficacy in other antibody-mediated conditions. Increased availability of Fc- and Fc receptor-targeting biologics might foster the development of personalized immunotherapies with the potential to induce sustained disease remission in patients with MG.

Efficacy and Safety of Low-to-Moderate Dose Oral Corticosteroid Treatment in Ocular Myasthenia Gravis

PURPOSE

To evaluate the response to corticosteroid therapy as a primary treatment for ocular myasthenia gravis.

METHODS

Patients diagnosed as having ocular myasthenia gravis by an acetylcholine receptor binding antibody test between January 2011 and September 2015 were included in the study and started receiving treatment with a corticosteroid. Patients with a blowout fracture, hyperthyroidism, diabetes mellitus, hypertension, cardiovascular disease, or history of strabismus surgery were excluded. Disappearance of diplopia and ptosis were considered a response to treatment.

RESULTS

Methylprednisolone therapy was administered to 29 patients (19 men and 10 women; average age: 49 ± 16.5 years) as an initial treatment. A total of 6 patients were lost to follow-up. Twenty-three of 29 patients (82.6%) were regarded as having presented a response to treatment. The average treatment duration was 3 weeks for patients responding to primary treatment. Eight patients complained of adverse effects from steroid therapy such as heartburn, insomnia, weight gain, and myalgia.

CONCLUSIONS

A corticosteroid could be considered as an initial treatment for patients diagnosed as having ocular myasthenia gravis by an acetylcholine receptor binding antibody test. [J Pediatr Ophthalmol Strabismus. 2018;55(5):339-342.].

Surgical Correction of the Intractable Blepharoptosis in Patients With Ocular Myasthenia Gravis

PURPOSE

Treatment of blepharoptosis caused by ocular myasthenia gravis (OMG) is challenging in patients with serious side effects or failed response to medical therapy. Only a few surgical reports have been published for refractory myathenic blepharoptosis. This study is aimed at the evaluation of the surgical outcome of blepharoptosis correction in intractable OMG patients.

METHODS

Twelve OMG patients who accepted frontalis sling with frontalis orbicularis oculi muscle (FOOM) flap for blepharoptosis correction were reviewed. Patients' demographies, perioperative changes of the interpalpebral fissure height (IPFH), margin reflex distance 1 (MRD1), levator function (LF), and quality of life (QOL) score were evaluated.

RESULTS

The duration of OMG ranged from 3 to 31 years. LF was normal in 6 patients, good in 5, and poor in 1. There is no significant change of LF before and after surgery. MRD1 improved significantly from -1.8 mm (range, 0 to -5 mm) preoperatively to 2.9 mm (range, 2-4 mm) postoperatively. IPFH improved significantly from 3.8 mm (range, 2-6 mm) preoperatively to 7.8 mm (range, 6-9 mm) postoperatively. Upper eyelid margin was above the pupil in all patients. QOL score improved significantly from 18.2 (range, 14-23) preoperatively to 5.8 (range, 0-10) postoperatively.

CONCLUSIONS

Our report reveals that surgical correction of the blepharoptosis is effective for patients with intractable OMG and that frontalis suspension with FOOM flap is a valuable option because of its ready availability and pliability. All patients are satisfied with the results, especially the improvement of QOL.

Clinical features, pathogenesis, and treatment of myasthenia gravis: a supplement to the Guidelines of the German Neurological Society

Myasthenia gravis (MG) is an autoimmune antibody-mediated disorder of neuromuscular synaptic transmission. The clinical hallmark of MG consists of fluctuating fatigability and weakness affecting ocular, bulbar and (proximal) limb skeletal muscle groups. MG may either occur as an autoimmune disease with distinct immunogenetic characteristics or as a paraneoplastic syndrome associated with tumors of the thymus. Impairment of central thymic and peripheral self-tolerance mechanisms in both cases is thought to favor an autoimmune CD4(+) T cell-mediated B cell activation and synthesis of pathogenic high-affinity autoantibodies of either the IgG1 and 3 or IgG4 subclass. These autoantibodies bind to the nicotinic acetylcholine receptor (AchR) itself, or muscle-specific tyrosine-kinase (MuSK), lipoprotein receptor-related protein 4 (LRP4) and agrin involved in clustering of AchRs within the postsynaptic membrane and structural maintenance of the neuromuscular synapse. This results in disturbance of neuromuscular transmission and thus clinical manifestation of the disease. Emphasizing evidence from clinical trials, we provide an updated overview on immunopathogenesis, and derived current and future treatment strategies for MG divided into: (a) symptomatic treatments facilitating neuromuscular transmission, (b) antibody-depleting treatments, and

Ocular myasthenia: diagnostic and treatment recommendations and the evidence base

PURPOSE OF REVIEW

Increasing rigor is being applied to medical decision making, but myasthenia gravis, commonly considered the best understood autoimmune disorder from a pathophysiological basis, lags other disciplines in the evidence base used to make clinical decisions. The review attempts to provide a focused, practical guideline for the diagnosis and treatment of ocular myasthenia within the limits of largely retrospective case series and expert opinion.

RECENT FINDINGS

Confirmation of clinical diagnosis continues to be challenging for ocular myasthenia. Despite the recognition of a new autoantigen, the muscle-specific kinase protein in generalized myasthenia gravis, it has been found to be only rarely identified in ocular myasthenia patients and therefore the majority of patients lack detectable autoantibodies and confirmation of a neuromuscular transmission disorder relies on specialized testing of single-fiber electromyography. The visual compromise of ocular myasthenia responds poorly to nonpharmacological and cholinesterase inhibitor therapy, and although corticosteroids are thought to be extremely effective, their toxicity is poorly defined in ocular myasthenia patients and whether they reduce the risk of development of generalized disease is not known.

SUMMARY

Rigorous clinical trials or large databases with outcome assessments are necessary in order to allow development of rational treatment strategies.

Ocular myasthenia: diagnosis, treatment, and pathogenesis

BACKGROUND

Although myasthenia gravis (MG) is often considered the best-understood autoimmune disorder and effective treatments have controlled life-threatening complications, the pathogenesis of ocular myasthenia (OM) remains enigmatic, and its clinical consequences offer therapeutic challenges.

REVIEW SUMMARY

About half of patients with MG present with visual complaints of droopy eyelids or double vision, and many will remain with purely ocular muscle weakness without generalized weakness, defined as OM. OM may be confused with disorders of the brainstem, ocular motor nerves, and eye muscles. Frustrating for the clinician, confirmatory tests such as the edrophonium test, serum acetylcholine receptor antibodies, and standard electrodiagnostic evaluations may fail to positively identify the clinical suspicion of OM. Patients may derive relief from nonpharmacologic interventions and cholinesterase inhibitors, but most will desire better symptom control with corticosteroids or need other immunosuppression. Early corticosteroid therapy may reduce the probability of generalization of the disease. The reasons for ocular muscle involvement by OM include physiologic and cellular properties of the ocular motor system and the unique immunology of OM, which, when better understood, will lead to novel treatments.

CONCLUSIONS

OM is a challenging disorder for the clinician and scientist, with both learning from the other for the betterment of the patient. The future requires answers to why the ocular muscles are so frequently involved by MG, whether the generalization of the disease may be limited by early corticosteroid treatment, and what treatment options may be developed which will improve symptoms without long-term complications.

Non-ptotic ocular myasthenia gravis: a common presentation of an uncommon disease

BACKGROUND

Myasthenia gravis (MG) is an acquired autoimmune disease of the neuromuscular junction which causes rapid muscle fatigue and weakness. Two thirds of all cases of myasthenia gravis (MG) initially manifest ptosis. In the absence of the characteristic variable ptosis, MG can present a challenge to the clinician. This article will review the current diagnostic and management strategies for MG.

CASE REPORTS

Five cases will be presented that did not initially present with ptosis. Each of these cases was previously misdiagnosed as a result of presentation of atypical myasthenia gravis signs and symptoms. The first two cases had signs and symptoms of a typical accommodative/vergence anomaly. The others manifested diplopia not normally associated with MG: one had a noncomitant vertical deviation; another had a stable 6(th) nerve palsy; and the third had a basic esotropia.

CONCLUSION

Although the hallmark findings of MG are ptosis and eye muscle palsy with variability, MG may present without ptosis, affect nonstriated muscles, and/or manifest either as a nonstrabismic vergence anomaly or as comitant nonvariable strabismic deviation.

Double trouble

A 78-year-old woman presented with vertical double vision. The Bielschowsky-Parks' three-step test suggested a left inferior rectus muscle paresis. Diagnostic testing confirmed the diagnosis of myasthenia gravis. Despite treatment with pyridostigmine bromide (mestinon) the diplopia persisted. She refused corticosteroid treatment and sought a second opinion, resulting in three unsuccessful strabismus surgeries to correct her ocular misalignment. The evaluation and management of ocular myasthenia gravis is reviewed and the appropriate timing of strabismus surgery is discussed.