eye findings in myasthenia gravis: diagnosis, evaluation, and treatment sophia m. chung, m.d. depts...
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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
Ocular Myasthenia Gravis
• >90% 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
Ocular Myasthenia Gravis
• Pure ocular disease occurs in 20% MG
– Later age
– Men > women
0
20
40
60
80
100
120
140
1st 2nd 3rd 4th 5th 6th 7th 8th
womenmen
n=868
Generalized Myasthenia (Grob et al. ‘81)
0
5
10
15
20
25
30
35
1st 2nd 3rd 4th 5th 6th 7th 8th
womenmen
Ocular Myasthenia (Grob et al. ‘81)
n=168
Ocular Myasthenia Gravis• 24 yo man complains of droopiness of
left upper lid-variable throughout the day
Ocular Myasthenia Gravis
• Ptosis– Isolation– Company of double vision– Variable– Often asymmetric– Fatigable– Worsens later in the day
Ocular Myasthenia Gravis
Ocular Myasthenia Gravis
• Patient photos
Ocular Myasthenia Gravis
• Ptosis (droopy eyelid)
– Cogan’s lid twitch
– Patient asked to look up after looking down
– Eyelid briefly over-elevated and appears to be waving
Ocular Myasthenia Gravis
• Video ptosis from MG
Myasthenia Gravis
• Double vision
– Variable
– May involve:
• One eye muscle
• Multiple eye muscles
• All eye muscles
Ocular Myasthenia Gravis
• Patient photos
Ocular Myasthenia Gravis
• Diagnosis
– Sleep test
– Ice test
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Ocular Myasthenia Gravis
• Before ice test
• After ice test
Ocular Myasthenia Gravis• Weakness of eyelid muscles
– Nearly always present
www.yorku.ca/earmstro/journey/images/facial.gif
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
Ocular Myasthenia Gravis
• Thyroid function tests
• 20% MG patients has concurrent thyroid disease
• Anti-nuclear antibody
• Erythrocyte sedimentation rate
Ocular Myasthenia Gravis
• Tensilon test
• Test dose
• Bolus
• Response within 30 sec
• Duration 2-5 minutes
• Look for change
Ocular Myasthenia Gravis
• Patient photos
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
Myasthenia Gravis
• CT chest• Thymoma 10-15% of MG
– (of thymomas, 50% have MG)– >age 30, males
• Thymus hyperplasia 60-80% – younger age, females
• Anti-Ach Rec Ab +95-100% of the time w/thymoma
Ocular Myasthenia Gravis
• No randomized clinical trials for pure ocular MG
• Treatment based on clinical experience, retrospective trials
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
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
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
Ocular Myasthenia Gravis
• Corticosteroids
• Side effects
– Mood swings -Cataract
– Sleep disorders -GERD
– Hyperglycemia -Osteoporosis
– Weight gain -Hypertension
Ocular Myasthenia Gravis
• Azathioprine• Mycophenolate mofetil• Cyclosporine A• Tacrolimus• Cyclophosphamide• Rituximab• Etanercept
Myasthenia Gravis
• Plasmapharesis (respiratory failure)
• Human Immunoglobulin
• Thymectomy
• Referral to Neurologist
Ocular Myasthenia Gravis
• Patient photos
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
• Patient photos
Ocular Myasthenia Gravis
• Conclusions
• >90% patients w/MG have eye finding
• Ptosis and diplopia
• 50% patients’ initial presentation of MG
– Most convert to generalized MG
Ocular Myasthenia Gravis
• Conclusions
• 20% MG is purely ocular
• Diagnosis often more challenging
• Treatment usually requires 2 or more drugs