Progressive Dysphagia Revealing Glioma: Diagnostic Overshadowing by Suspected Myasthenia Gravis.

UNLABELLED: Progressive dysphagia in older adults presents a diagnostic challenge with a broad differential including neuromuscular, structural and malignant causes. Dysphagia associated with aspiration may lead to significant respiratory compromise requiring intensive care management. We report the case of a 78-year-old patient with rheumatoid arthritis treated with methotrexate who presented with progressive dysphagia to solids and liquids, weight loss, and cough. She subsequently developed aspiration pneumonia complicated by repeated type 2 respiratory failure and required mechanical ventilation. Initial investigations focused on aspiration pneumonitis and possible neuromuscular disease, particularly myasthenia gravis, given the presence of bulbar symptoms and an insensate epiglottis on nasendoscopy. However, subsequent magnetic resonance imaging of the brain demonstrated a glioma explaining the progressive bulbar dysfunction. This case demonstrates diagnostic overshadowing, as recurrent type 2 respiratory failure was repeatedly managed as aspiration pneumonia, delaying the diagnosis of glioma. Early neuroimaging should be considered in patients with progressive dysphagia when initial investigations fail to explain symptoms.

LEARNING POINTS: Progressive dysphagia in an older adult warrants a broad differential - neuromuscular, structural and intracranial causes - not just aspiration-related respiratory disease.A bulbar syndrome (insensate epiglottis, dysphagia) can be produced by an intracranial lesion as well as by myasthenia gravis; negative acetylcholine receptor antibodies do not fully exclude either possibility and should not halt the diagnostic search.Recurrent type 2 respiratory failure that responds poorly to treatment for presumed aspiration pneumonia should prompt reconsideration of the working diagnosis, rather than repeated management of the same presumed cause - a pattern of diagnostic overshadowing and anchoring bias.Early neuroimaging should be considered when dysphagia and respiratory failure evolve atypically or fail to resolve despite appropriate treatment, as magnetic resonance imaging was ultimately pivotal in revealing the underlying glioma in this case.