A case of diplopia and arm weakness

• Published in: BMJ Vol. 339; no. nov25 2; p. b4555
• Main Authors: Sennik, D K, Suresh, D, Goodall, E, Lane, R J M
• Format: Journal Article
• Language: English
• Published: England British Medical Journal Publishing Group 25.11.2009; BMJ Publishing Group LTD
• Subjects: Aged, 80 and over; Arm; Blepharoptosis - etiology; Cholinesterase Inhibitors; Confidence intervals; Diplopia - etiology; Drug dosages; Edrophonium; Female; Humans; Immunoglobulins; Myasthenia Gravis - complications; Myasthenia Gravis - diagnosis; Studies; Thyroid gland; Tomography
• ISSN: 0959-8138; 1468-5833; 1756-1833
• DOI: 10.1136/bmj.b4555

A brainstem lesion, such as a tumour or stroke, could cause similar cranial symptoms but would typically also result in long tract signs and possibly additional features such as sensory impairment and ataxia. 3 Investigations and management Investigation to confirm the diagnosis in cases of suspected myasthenia gravis should include the edrophonium (Tensilon) test, electromyography, and measurement of serum acetylcholine receptor antibodies. 1 2 Our patient had an edrophonium (Tensilon) test (figs 3-6 ), and ptosis improved greatly one minute after administration of the drug (fig 4). 10 Alternative immunosuppressants include methotrexate, cyclophosphamide, mycophenolate mofetil, or tacrolimus, but the evidence base for these is lacking. 10 There are case reports that rituximab, a monoclonal antibody that suppresses B cells, is beneficial in refractory cases. 11 Patients on long term steroids should be considered for bone protection treatment. 12 Acute myasthenic crisis-characterised by rapid exacerbation of symptoms of weakness, with or without respiratory muscle involvement-can be treated with plasma exchange or intravenous immunoglobulins. 1 The thymus regulates immune tolerance and the removal of T cells that respond to self antigens.