Asymmetric Involvement of Abductor Digiti Minimi Found by Repetitive Nerve Stimulation in Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune disease involving neuromuscular junction, which is characterized as fluctuating weakness and fatigue in various muscle groups. Amplitude decrement is often found in involved muscles and sometimes in clinically normal muscles in low frequency repetitive nerve stimulation (RNS) test. The abnormal response elicited in RNS is mostly seen in facial muscles or proximal limb muscles. Distal involvement was reported as a rare manifestation of MG, alone or in combination with other muscle involvement. We report a MG patient with asymmetric abductor digiti minimi (ADM) involvement.