Delayed Diagnosis of Atypical Presentation of Myasthenia Gravis.

UNLABELLED: Myasthenia gravis is an autoimmune disorder affecting the neuromuscular junction, resulting in muscle fatiguability and weakness. The pathological characteristics of the disorder include ocular weakness resulting in diplopia and/or ptosis. More generally, the disease can result in fluctuant weakness of skeletal muscle, predominantly affecting ocular, bulbar and respiratory muscles. Autoimmunity in this instance is mediated by IgG anti-acetylcholine receptor antibodies that results in an impaired structure of postsynaptic neurotransmission. Approximately 15% of patients with myasthenia gravis present with bulbar symptoms, of which isolated bulbar symptoms are seen only on occasion. As with our patient, this presentation is most commonly seen in men with late-onset myasthenia gravis. We present a case of an 83-year-old male who presented with a 1 year history of dysphagia for solids and fatigable dysarthria. Following a diagnosis of myasthenia gravis, he was initiated on corticosteroid treatment. He later descended into myasthenic crisis, requiring invasive ventilation measures due to a failure of both non-invasive ventilation and intravenous immunoglobulin G (IVIG) to achieve therapeutic goals.

LEARNING POINTS: Isolated bulbar symptoms in an elderly man warrants consideration of myasthenia gravis to be included in the differential diagnosis.There is possibly an increased risk of myasthenic crisis in late-onset isolated bulbar myasthenia gravis.Empirical treatment for myasthenia gravis must be administered within a hospital setting, paying attention to respiratory tract infection and corticosteroid treatment as triggers for myasthenic crisis.