Chief Complaint: 32-year-old female examined in oculoplastics for evaluation and repair of LUL ptosis.
History of Present Illness: Patient noted progressive ptosis of the LUL for 5 years, which now blocks her vision. She has no other complaints or problems.
POH/PMH: Healthy, no history of eye problems.
Patient maintains chin up position. There's RUL retraction and marked ptosis OS. Palpebral fissures are 10 mm OD and 5 mm OS with palpebral function of 15 mm OD and 10 mm OS. There is a twitching of the LUL when the patient looks up after looking down.
This young female presented with progressive LUL ptosis, Cogan's lid twitch, and bilateral ophthalmoplegia on upgaze. The diagnosis of myasthenia gravis was made. After careful history taking, she states that her RUL retraction is better and her LUL ptosis is less in the morning. Because of equal innervation of the levator (Hering's law), asymmetric ptosis may cause lid retraction on the opposite side as the patient is attempting to maintain lid opening. With lid retraction, you should think of thyroid disease, but usually we do not see ptosis with Grave's ophthalmopathy (however 5% of myasthenia gravis patients could have underlying Grave's).
Myasthenia gravis, although a systemic disease, may present with only ocular symptoms 50% of the time. Patients often present complaining of binocular diplopia, and the ocular motility deficits may mimic other neurologic disorders, e.g. 6th nerve palsy, 4th nerve palsy, internuclear ophthalmoplegia, etc... The hallmark signs of myasthenia gravis include: fluctuation & fatigability, diplopia, ophthalmoplegia, ptosis, weakness of jaw, weak neck/trunk/limbs, dysphagia, hoarseness, dysarthria, and dyspnea. Clearly, some of these manifestations may be life threatening.
Because some patients with myasthenia may have an underlying thymoma, a CT scan of the chest should be performed. In this case it was negative.
We performed the Tensilon test (edrophonium chloride) IV. This is a short acting acetylcholinesterase inhibitor.Photo of lids before Tensilon. Note the RUL retraction and LUL ptosis.
Diagnosis of myasthenia gravis can be confirmed by the presence of anti-Ach receptor antibodies, but a NEGATIVE result does not rule-out myasthenia gravis because the panel of antibodies screened may not be complete. Also, a NEGATIVE Tensilon test does not rule-out the disease either. If myasthenia gravis is still suspected, then a Prostigmin test (longer acting acetylcholinesterase inhibitor) should be given with atropine (prevent life threatening bradycardia and respiratory depression). The ice or sleep test may also be useful.
Suggested citation format: Doan A, Nerad J, Kardon R: Myasthenia Gravis: 32-year-old female with progressive LUL ptosis for several years. February 21, 2005 [updated July 12, 2007]; Available from: http://www.EyeRounds.org/cases/case2.htm.
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