2009 Southern Regional Meeting Abstracts

Case Report: Introduction: Myasthenia Gravis [MG] is characterized by a fluctuating degree and variable combination of weakness in ocular, bulbar, limb, and respiratory muscles. Occurrence with rheumatoid arthritis [RA] is rare, especially without use of D-penicillamine.
Case presentation: A 25 years old African American female with history of RA diagnosed in 2004, was admitted with 4 month history of progressive,diffuse weakness since the delivery of her child. She had difficulty with activities of daily living including caring for her baby. Her RA had improved after restarting her methotrexate, prednisone and hydroxychloroquine. She denied any visual problems, muscle soreness, dysphonia, dysphagia or dysarthria. She had multiple ER visits for falls. Her examination was significant for fluctuating weakness in extremities. No focal deficits were evident. Her laboratory tests showed high titres of CCP antibodies but others including CPK, aldolase, TSH, hepatitis panel, HIV, APLS panel were unrevealing. A bedside EMG revealed evidence of neuromuscular transmission defect of post synaptic variety and her tensilon test was positive. Acetylcholine receptor Antibodies were present in high titres[217 nmol/L]. She was initially treated with Pyridostigmine bromide and prednisone in incremental doses with good clinical relief.
Discussion: MG is the most common disorder of neuromuscular transmission, with fluctuating skeletal muscle weakness, often with true muscle fatigue. Fifty percent of patients present with ocular symptoms of ptosis and/or diplopia, fifteen precent present with dysarthria, dysphagia, and fatigable chewing. Symptomatic treatment with pyridostigmine is the main stay of therapy. Immunotherapeutic drugs are commonly needed including prednisone, azathioprine, and mycophenolate. Intravenous immunoglobulins and plasmapheresis have been used in severe cases like myasthenic crisis. Patients with thymoma clearly benefit from thymectomy.
Conclusion: The differential diagnosis for weakness in RA patient can be vast including inflammatory myositis, viral myositis, drug induced, thyroid disease, motor neuron diseases like ALS, myopathies and muscular dystrophies. Our case highlights the rare occurrence of second autoimmune disease as a cause of weakness in RA patient.