Ophthalmologic clinical features of ocular myasthenia gravis

Abstract

To investigate the clinical features of ocular myasthenia gravis (OMG) in ophthalmology. A total of 28 patients with ptosis or diplopia who were followed for at least 6 months between March 2016 and February 2022 were included in this study. The clinical symptoms of the patients and test results were analyzed. According to the positivity of serologic or electrophysiologic test, these patients were divided into 2 groups (positive and negative OMG results) and according to the clinical symptoms of diplopia or ptosis for comparison. Ptosis, diplopia, and both ptosis and diplopia were present in 6 (21.43%), 14 (50.0%), and 8 (28.57%) patients, respectively. Acetylcholine receptor auto-antibody (AchR Ab) was positive in 16 (57.14%) of 28 patients and the ice test was positive in 13 (92.86%) of 14 patients with ptosis. Abnormal thymic lesions were presented in 7 (25.0%) patients, and a definite improvement in response to pyridostigmine was observed in 27 (100.0%) patients. Both ptosis and diplopia were significantly higher in the group with positive results than that in the negative results group ( P = .025). In addition, both horizontal and vertical diplopia was significantly higher in the group with AchR Ab titer > 5.0 than that in the group with AchR Ab titer < 5.0 ( P = .041). After excluding cranial nerve palsy, if there is ptosis and diplopia, especially vertical diplopia, the possibility of OMG should be considered.

The nurse's guide to myasthenia gravis

“…Instructing the patient to wear a patch over the affected eye can mitigate visual symptoms. Eyelid weakness in ptosis increases when a patient takes an upward gaze for 15 seconds 13,15-17. The Cogan lid twitch may also be elicited in MG.…”

“…The eyelid overshoots or twitches before it returns to the normal ptotic position. Improvement in ptosis after applying an ice pack to the affected eye(s) for 5 minutes is a symptom of MG 13,15-17…”

“…Proximal muscle weakness is more common than generalized weakness in MG 15-17. For example, the second most common manifestations are bulbar symptoms related to cranial nerves V (trigeminal), VII (facial), IX (glossopharyngeal), X (vagus), XI (accessory), and XII (hypoglossal) 15-17. Bulbar refers to the muscles innervated by motor neurons originating in the medulla or pons 15-17.…”

“…For example, the second most common manifestations are bulbar symptoms related to cranial nerves V (trigeminal), VII (facial), IX (glossopharyngeal), X (vagus), XI (accessory), and XII (hypoglossal) 15-17. Bulbar refers to the muscles innervated by motor neurons originating in the medulla or pons 15-17. MG's most common bulbar sign is weakness of facial muscles, which may be asymmetrical and misdiagnosed as Bell palsy 15-17.…”

“…Patients may appear sad or angry from weak facial muscles and avoid social interaction. Speech may be affected, such as by having difficulty in articulation, having a nasal voice quality, lisping, and/or slurring words 15-19. Differential diagnoses, such as amyotrophic lateral sclerosis, should be explored relative to the hypernasal speech quality 15-19.…”