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

Generalized Myasthenia (Grob et al. ‘81)

140 120 100 80 women men

n=868

60 40 20 0 1st 2nd 3rd 4th 5th 6th 7th 8th

Ocular Myasthenia (Grob et al. ‘81)

35 30 25 20 15 10 5 0 1st 2nd 3rd 4th 5th women men

n=168

6th 7th 8th

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 www.globalspine.net/best_position_sleeping.html

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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 www.eorthopod.com/images/ContentImages/spine

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 – Sleep disorders – Hyperglycemia – Weight gain -Cataract -GERD -Osteoporosis -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