Eye Findings in Myasthenia Gravis: Diagnosis, Evaluation, and Treatment

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Eye Findings in Myasthenia Gravis Diagnosis,
Evaluation, and Treatment

• Sophia M. Chung, M.D.
• Depts of Ophthalmology
• Neurology and Psychiatry
• Saint Louis University School of Medicine

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Ocular Myasthenia Gravis

• gt90 patients w/MG have eye finding
• Ptosis (droopy lid)
• Diplopia (double vision)
• 50 patients initial presentation of MG
• Most convert to generalized MG
• Within 2 years

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Ocular Myasthenia Gravis

• Pure ocular disease occurs in 20 MG
• Later age
• Men gt women

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Generalized Myasthenia (Grob et al. 81)
n868
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Ocular Myasthenia (Grob et al. 81)
n168
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Ocular Myasthenia Gravis

• 24 yo man complains of droopiness of left upper
  lid-variable throughout the day

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Ocular Myasthenia Gravis

• Ptosis
• Isolation
• Company of double vision
• Variable
• Often asymmetric
• Fatigable
• Worsens later in the day

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Ocular Myasthenia Gravis
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Ocular Myasthenia Gravis

• Patient photos

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Ocular Myasthenia Gravis

• Ptosis (droopy eyelid)
• Cogans lid twitch
• Patient asked to look up after looking down
• Eyelid briefly over-elevated and appears to be
  waving

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Ocular Myasthenia Gravis

• Video ptosis from MG

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Myasthenia Gravis

• Double vision
• Variable
• May involve
• One eye muscle
• Multiple eye muscles
• All eye muscles

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Ocular Myasthenia Gravis

• Patient photos

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Ocular Myasthenia Gravis

• Diagnosis
• Sleep test
• Ice test

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Ocular Myasthenia Gravis

• Before ice test
• After ice test

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Ocular Myasthenia Gravis

• Weakness of eyelid muscles
• Nearly always present

www.yorku.ca/earmstro/journey/images/facial.gif
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Ocular Myasthenia Gravis

• Diagnosis anti-acetylcholine receptor Ab
• Present in 80-90 generalized MG
• Present in 50 ocular MG
• Level has no correlation with disease activity

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Ocular Myasthenia Gravis

• Thyroid function tests
• 20 MG patients has concurrent thyroid disease
• Anti-nuclear antibody
• Erythrocyte sedimentation rate

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Ocular Myasthenia Gravis

• Tensilon test
• Test dose
• Bolus
• Response within 30 sec
• Duration 2-5 minutes
• Look for change

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Ocular Myasthenia Gravis

• Patient photos

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Ocular Myasthenia Gravis

• Repetitive stimulation test
• Positive 20-30 ocular MG
• Single fiber EMG
• Eyelid muscles or forehead
• 85-100 sensitivity

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Ocular Myasthenia Gravis

• Chest CT
• Thymomas present in 15 all MG patients
• Considered rare-uncommon in ocular MG
• Presence warrants surgery

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Myasthenia Gravis

• CT chest
• Thymoma 10-15 of MG
• (of thymomas, 50 have MG)
• gtage 30, males
• Thymus hyperplasia 60-80
• younger age, females
• Anti-Ach Rec Ab 95-100 of the time w/thymoma

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Ocular Myasthenia Gravis

• No randomized clinical trials for pure ocular MG
• Treatment based on clinical experience,
  retrospective trials

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Ocular Myasthenia Gravis

• Treatment
• Withdraw medications that might exacerbate MG
• Long list cardiac drugs, antibiotics,
  anti-epileptics, psychiatric drugs
• Most common aminoglycosides and beta-blockers

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Ocular Myasthenia Gravis

• Pyridostigmine (Mestinon)
• Less effective in pure ocular MG
• 50 patients respond
• Ptosis responds better than diplopia
• Side effects gastrointestinal
• Contraindications bradycardia, reactive airway
  disease, BPH

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Ocular Myasthenia Gravis

• Corticosteroids
• Start low (5-10mg) and increase slowly until
  symptoms improve
• Maintain resolution
• Slow taper
• Recurrence common despite slow taper
• Improvement of ptosis diplopia 72-96 patients

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Ocular Myasthenia Gravis

• Corticosteroids
• Side effects
• Mood swings -Cataract
• Sleep disorders -GERD
• Hyperglycemia -Osteoporosis
• Weight gain -Hypertension

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Ocular Myasthenia Gravis

• Azathioprine
• Mycophenolate mofetil
• Cyclosporine A
• Tacrolimus
• Cyclophosphamide
• Rituximab
• Etanercept

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Myasthenia Gravis

• Plasmapharesis (respiratory failure)
• Human Immunoglobulin
• Thymectomy
• Referral to Neurologist

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Ocular Myasthenia Gravis

• Patient photos

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Myasthenia Gravis Thymectomy

• Data for generalized MG helpful early in disease
• Promotes long term clinical improvement under the
  age of 50
• Unclear role with pure ocular MG
• Always indicated with the presence of thymoma
• 50 chance of malignancy

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• Patient photos

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Ocular Myasthenia Gravis

• Conclusions
• gt90 patients w/MG have eye finding
• Ptosis and diplopia
• 50 patients initial presentation of MG
• Most convert to generalized MG

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Ocular Myasthenia Gravis

• Conclusions
• 20 MG is purely ocular
• Diagnosis often more challenging
• Treatment usually requires 2 or more drugs