Tongue Atrophy and Myopathy Mimicking EMG Findings in a Case with Acethylcholine Receptor-Positive Myasthenia Gravis

Abstract

Myasthenia gravis has various clinical presentations and can mimic multiple diseases. Isolated oro-facial muscle weakness and tongue atrophy at the time of presentation are rare. Besides the clinical picture, electrodiagnostic findings also can mimic various conditions and cause diagnostic difficulties. Our patient was a 28-year-old female admitted with non-fluctuating, progressive fatigue while talking and difficulty in swallowing. Her examination revealed tongue atrophy and fasciculations, ptosis, and facial weakness. Repetitive nerve stimulation revealed decrement in two muscle-nerve pairs. Electromyography demonstrated low amplitude and polyphasic motor unit action potentials at facial and neck muscles. She was diagnosed as having myasthenia gravis and was treated with pyridostigmine and methylprednisolone. Our case demonstrates that myasthenia gravis can present with tongue atrophy with fasciculations, oro-facial weakness, and electromyography findings mimicking myopathy. All these features were separately described during the disease course but our patient showed these features at presentation time. Repetitive nerve stimulation was the hallmark in correct diagnosis.