Abstract: A 67 y/o WM c/o sudden onset ptosis and variable diplopia, which is worse in the evening. Positive ice pack test, labs, and neurologic evaluation confirms ocular myasthenia gravis.
I. Case History A. Patient Demographics: 67 y/o WM B. Chief Complaint: Sudden onset variable, non‐painful diplopia and ptosis – one week duration C. Ocular/Medical History: hypertension, high cholesterol, and atrial fibrillation D. Medications: atenolol, simvastatin, niaspan, and coumadin II. Pertinent Findings A. Clinical − PERRL (‐) APD − EOM’s FROM OU − Hypertropia (4∆ ILHyperT) – variable throughout the examination − Initial MRD: 3mm OD and 6mm OS‐ fatigable and variable throughout the examination − (+) Cogan’s Lid twitch [Video] − (+) ice pack test [Video] − (+) prolonged upgaze test [Video/Photo] B. Physical − (‐) dysphasia, dyspnea, dysarthria or ataxia C. Laboratory Studies − ACH‐R, TSH D. Radiology Studies − CT of Chest, MRI/MRA of Brain with and without contrast III. Differential Diagnosis in this case A. Primary Diagnosis − Ocular Myasthenia Gravis B. Other Differentials − partial cranial nerve 3 palsy − Horner’s syndrome − thyroid eye disease − decompensated phoria with myogenic/senile ptosis − intracranial mass IV. Diagnosis and Discussion A. Elaborate on the condition − Chronic, autoimmune disease affecting nicotinic acetylcholine receptors at neuromuscular junctions of skeletal muscle − Voluntary skeletal muscle involvement can be generalized throughout the body or remain localized to ocular manifestations − Typically affects women in the 2nd‐3rd decade of life and men in the 6th and 7th decade of life − Ocular manifestations presenting symptoms in up to 75% of cases − More than 50% of patients presenting with ocular myasthenia will progress to generalized within 2 years of onset − Pathophysiology Review − Diagnostic Testing Edrophonium Ice pack test Sleep test Serologic Testing B. Unique features of Ocular Myasthenia Gravis − Ptosis and diplopia‐ which is variable and fatigable − Ophthalmoplegia may mimic any disorder of eye movements or complete ophthalmoplegia can occur − Emergent referral to intensive care unit if signs of ventilatory fatigue, dyspnea or dyphagia to prevent respiratory arrest and ultimately death V. Treatment and Management A. Our patient was referred to a neurologist and was treated with oral pyridostigmine bromide. The diplopia resolved and ptosis was greatly improved. B. Other Treatment considerations − Immunosuppresive therapies − Oral steroids (decreases the conversion to generalized myasthenia gravis) − Thymectomy − Other ocular management C. Bibliography − Levin LA, Arnold, AC. Neuro‐Ophthalmology; The Practical Guide. Thieme Medical Publishers Inc. 2005. − Pane A, Burdon M, Miller N. The Neuro‐Ophthalmology Survival Guide. Mosby Elsevier. 2006. − Biousse V, Newman N. Neuro‐Ophthalmology Illustrated. Thieme Medical Publishers Inc. 2009. − Kupersmith MJ, et al. Beneficial Effects of Corticosteroids on Ocular Myasthenia Gravis. Archives of Neurology; Vol 53, August 1996. − Chatzistefanou KI, et al. The Ice Pack Test in the Differential Diagnosis of Myasthenic Diplopia. American Academy of Ophthalmology 2009; 116: 2236‐ 2243. − Lavrnic, D et al. The Features of Myasthenia Gravis with Autoantibodies to MuSK. Journal of Neurology, Neurosurgery, and Psychiatry 2005; 76:1099‐1102. − Kupersmith MJ, Ying G. Ocular Dysfunction and Ptosis in Ocular Myasthenia Gravis: Effects of Treatment. British Journal of Ophthalmology 2005; 89:1330‐ 1334. − Comer, RM et al. Causes and Outcomes for Patients Presenting with Diplopia to an Eye Casualty Department. Eye 2007; 21:413‐418. − Matney SE, Huff DR. Diagnosis and Treatment of Myasthenia Gravis. The Consultant Pharmacist 2007; 22:239‐249. − Kupersmith MJ, Latkany R, Homel, P. Development of Generalized Disease at 2 Years in Patients with Ocular Myasthenia Gravis. Archives of Neurology 2003; 60:243‐248.
VI. Conclusion
This case demonstrates classic signs of ocular myasthenia gravis. Myasthenia Gravis may be a diagnostic challenge because it can mimic any eye movement disorder. Thorough ocular examination and consideration of systemic associated symptoms is vital for appropriate diagnosis, and in certain cases, emergent referral and treatment is life saving.