Ocular myasthenia gravis

Case Report: Treatment of Myasthenic Ptosis with Topical Ocular Oxymetazoline

SIGNIFICANCE

Ptosis is often the hallmark finding in ocular and general myasthenia gravis. Reduction of ptosis has been achieved with oral and topical ocular medications. However, these medications can result in systemic and ocular adverse effects. A novel eye drop seems to be effective in reducing ptosis while minimizing adverse effects.

PURPOSE

This case report aimed to demonstrate the efficacy of topical oxymetazoline hydrochloride 0.1%, an α-adrenergic agonist, in temporary elimination of ptosis associated with myasthenia gravis.

CASE REPORT

A 68-year-old woman with a history of myasthenia gravis and long-standing ptosis in the right eye presented to improve the asymmetrical appearance of her eyelids. One drop of oxymetazoline hydrochloride 0.1% was instilled in the right eye of the patient. Within 2 hours, the ptosis was eliminated, the margin-reflex distance 1 increased by 2.0 mm, and the superior visual field measured by a superior 36-point screening test increased by 15 points. The effect lasted for at least 7 hours. Of note, there was a decrease in elevation of the contralateral nonptotic eyelid that did not receive a drop of oxymetazoline, which might occur only in myasthenia gravis. Further evaluation is warranted.

CONCLUSIONS

Oxymetazoline 0.1% is effective in reducing and potentially eliminating ptosis related to ocular myasthenia gravis for up to 7 hours.

Open source modular ptosis crutch for the treatment of myasthenia gravis

INTRODUCTION

Pharmacologic treatment of Myasthenia Gravis presents challenges due to poor tolerability in some patients. Conventional ptosis crutches have limitations such as interference with blinking which causes ocular surface drying, and frequent irritation of the eyes. To address this problem, a modular and adjustable ptosis crutch for elevating the upper eyelid in Myasthenia Gravis patients has been proposed as a non-surgical and low-cost solution.

AREAS COVERED

This paper reviews the literature on the challenges in the treatment of Myasthenia Gravis globally and focuses on a modular and adjustable ptosis crutch that has been developed by the Medical Device Laboratory at the University of Cape Town.

EXPERT COMMENTARY

The new medical device has potential as a simple, effective and unobtrusive solution to elevate the drooping upper eyelid(s) above the visual axis without the need for medication and surgery. Access to the technology is provided through an open source platform which makes it available globally. Open access provides opportunities for further open innovation to address the current limitations of the device, ultimately for the benefit not only of people suffering from Myasthenia Gravis but also of those with ptosis from other aetiologies.

Treatment of ocular myasthenia gravis

OPINION STATEMENT

Myasthenia gravis (MG) is an autoimmune disorder that is characterized by variable weakness and fatigability. Often, MG presents with only ocular symptoms such as ptosis and diplopia. Treatment of ocular MG is aimed at relieving the symptoms of ptosis and diplopia, as well as preventing the development of generalized MG symptoms. Immune suppression with steroids is often the main therapy. Steroid doses must be increased slowly because of a risk of precipitating myasthenic crisis. After achieving the highest target dose, steroids are then slowly tapered down to the lowest effective dose. Often, acetylcholinesterase inhibitors such as pyridostigmine and neostigmine are also employed to help control symptoms. When steroids are contraindicated, acetylcholinesterase inhibitors can be tried as the primary therapy. Steroid-sparing agents such as azathioprine and mycophenolate may also have a role in treating ocular MG. Other treatments for MG include plasmapheresis, intravenous immunoglobulin, and other immunosuppressive agents, but these are rarely required for ocular MG. Patients should also be evaluated for thymoma. Thymoma should be resected surgically. Ocular MG without thymoma is not usually treated with thymectomy. Topical agents may be useful as additional therapy for mild or moderate ptosis. Nonpharmacologic treatments include occlusive devices, prisms, eyelid supports, contact lenses, and (in long-standing, stable cases) strabismus surgery or eyelid elevation surgery.

A case report of myasthenia gravis localized to the larynx

This report describes a very rare case of myasthenia gravis (MG) localized to the larynx, with the onset of dyspnea requiring tracheotomy. The vocal cords of this patient were fixed in the paramedian position. Under fiberscopic observation, improvement of laryngeal function was demonstrated after intravenous injection of edrophonium. However, no voice change occurred. The posterior crico-arytenoid muscle has the sole responsibility of abducting the vocal cord; thus, it is concluded that the dyspnea was caused by the selective paralysis of this muscle. We suggest that MG should be considered in cases of vocal cord paralysis of unknown etiology.

Ocular myasthenia revisited: Insights from pseudo-internuclear ophthalmoplegia

Ocular myasthenia can mimic central disorders of eye movements. We compared horizontal saccades in two patients with myasthenia gravis who presented as pseudo-internuclear ophthalmoplegia (pseudo-INO), two patients with true INO due to multiple sclerosis (MS), and five healthy subjects. In myasthenics, peak velocity of horizontal saccades was similar to, or greater than, controls; in MS patients, adducting saccades were slower than controls. Differences between the peak velocity of abducting and adducting eyes for each saccade were similar to controls for myasthenic pseudo-INO, but greater than controls for true INO. Using the technique of phase-plane analysis, in which eye velocity is plotted against eye position, we found that initial components of abducting and adducting saccades in the myasthenics were as conjugate as controls, even though later components of myasthenic saccades were highly and variably disjunctive. Conversely, phase planes of saccades in true INO showed disjunctive early components of abducting and adducting saccades. Two hypotheses have been offered to account for preservation of fast saccades despite reduced range of eye movements in ocular myasthenia. The first is intrasaccadic neuromuscular fatigue, which is variable over time. Our finding that initial components of saccades were consistently conjugate in the myasthenics gives support to a second hypothesis: selective sparing of pale global fibers, which are important for generating highspeed eye movements, and which are unique amongst extraocular fibers in possessing well developed synaptic folding.

Ptosis as an initial manifestation of orbital lymphoma: a case report

Ptosis on its own is an infrequent initial manifestation of orbital lymphoma. Orbital lymphoma usually presents as a palpable mass with proptosis, diplopia, and conjunctival ("salmon-pink") swelling. We report here a 62-year-old female patient who presented with right eye ptosis. The initial imaging study showed an indistinct enlargement of the superior rectus-levator muscle complex. After 3-4 months, ptosis and upward gazing movement were further restricted. The imaging study revealed a definite soft-tissue mass in the superior orbit surrounding the superior rectus-levator muscle complex. A tumor biopsy through anterior orbitotomy revealed a large diffuse B-cell lymphoma. With the experience of this case, we suggest that orbital lymphoma should be included in the differential diagnosis of ptosis accompanied by impairment of levator muscle function.

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.