MYASTHENIA GRAVIS-ASSOCIATED SYSTEMIC VASCULITIS AND MYOCARDITIS WITHINVOLVEMENT OF THE CARDIAC CONDUCTING TISSUE

We describe unexpected autopsy findings in an elderly woman with myast henia gravis (MG) who had myocarditis of the working and conducting my ocardium and coronary and renal vasculitis. Myasthenia gravis, charact erized by autoantibodies to the acetylcholine receptor in the postsyna ptic cell membrane, may be associated with other autoimmune disorders. An additional manifestation of autoimmunity is the presence of heart muscle antibodies, which may be the basis for myocarditis, which has b een reported in up to 60% of MG patients at autopsy. Although myocardi tis of the working myocardium is rather common, conduction system myoc arditis and systemic vasculitis have not been previously reported in M G.