BIOGRAPHY I am an advanced trainee in Internal medicine from Waikato. I have also completed respiratory training in England prior to moving to NZ. ABSTRACT Hickum’s Dictum: Two Atypical Presentations of Myasthenia Gravis in Graves’ Disease Rebello R 1, Sehgal S 1,
Bukhari W 2, and Wolmarans L 1 Aims: We present two patients with Graves’ disease, bilateral ptosis, fatigability and skeletal muscle weakness. Our case evaluation reveals an association between the two common autoimmune diseases, and demonstrates the potential adverse effects of delayed diagnosis. Methods/Case Description: Patient 1 is a 28 year old Maori man in ICU with undiagnosed Graves’ disease presenting following his second respiratory arrest, preceded by several months of dysphagia & fatigability. Exophthalmos, ptosis and muscle weakness were present on examination. Thyroid function tests revealed the following FT4 52.0( 12-20) pmol/l, (FT3 ) 14.6(3.1-6.8) pmol/l, TSH<0.02 mU/l. Patient 2 is a 66 year old Cantonese woman with established Graves’ disease on medical therapy since September 2015. Examination revealed bilateral ptosis and right lateral rectus palsy. Thyroid function tests revealed a FT4 67(12-20) pmol/l, (FT3 ) 20.6(3.1-6.8) pmol/l, TSH<0.02. Results: Patient 1 had Nicotinic Acetyl Choline Receptor antibodies of >20.0 and Patient 2’s titre was 5.35 nmol/l (<0.44nmol/l). EMG findings confirmed Myasthenia Gravis in patient 1 and was not performed in patient 2, an ice pack test for ptosis was negative. Both patients were commenced on Carbimazole therapy. Patient 2 developed neutropenia on Carbimazole requiring a total thyroidectomy for Graves’ disease management before confirming the diagnosis of Myasthenia Gravis. Both patients were commenced on steroids and anticholinesterase therapy when the diagnosis of Myasthenia gravis was confirmed. Conclusions: Autoimmune thyroid disease occurs in 8.2% of patients with Myasthenia Gravis (1). The prevalence of Myasthenia Gravis in Graves’ disease is 0.14% (2). Both disorders share common autoimmune mechanisms, and both are associated with an increased risk of Graves opthalmopathy (3). Ocular signs in both diseases closely resemble each other with the presence of ptosis suggesting co-existing Myasthenia Gravis (4,5). Both disorders complicate the presentation, evaluation, successful medical and surgical management of each other (6). References: 1. Chen YL, Yeh JH, Chiu HC. Clinical features of
myasthenia gravis patients with autoimmune thyroid disease in Taiwan. Acta
Neurologica Scandinavica. 2013 Mar 1;127(3):170-4. |