What is the appearance of a patient with myasthenia gravis (MG)?

Updated: Aug 27, 2018
  • Author: Abbas Jowkar, MD; Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
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Answer

The general appearance of a myasthenic patient gives an impression of a person who is sleepy or with a sad-looking facial appearance caused by ptosis and facial weakness. It is often helpful to look at old photographs of the patient from earlier years, for example, by examining his or her driver’s license. Eye findings are common, with ptosis and extraocular muscle weakness occurring in more than 50% of patients at the time of presentation and in more than 90% of patients sometime during their illness. The patient who has no ptosis first thing in the morning and whose eyes are completely closed at night almost certainly has MG. Ptosis can be unilateral and, if bilateral, is usually asymmetric. Persistently symmetric ptosis is more suggestive of a myopathic etiology, especially chronic progressive external ophthalmoplegia (CPEO) or oculopharyngeal muscular dystrophy (OPMD). MG is one of few disorders that can cause complete unilateral (or rarely bilateral) ptosis or a history of ptosis alternating sides over time. Many patients describe diplopia. Milder involvement may produce blurred vision or a halo around objects. Photophobia, with worsening of either ptosis or diplopia in bright light, is not uncommon and some patients are so troubled by this that they wear dark sunglasses. Patients may give history of frequent changes in eyeglasses to correct blurry vision. Patients with LEMS rarely, if ever, present with ocular symptoms. Myasthenic weakness of the ocular muscles have been known to mimic CN III, CN IV, and CN VI nerves palsies and, rarely, an internuclear ophthalmoplegia. Unlike true CN III nerve palsies, however, MG never affects papillary function. Fixed extraocular muscle weakness may occur late in the illness, especially if untreated.


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