Severe Seronegative Myasthenia Gravis Revealed by Rapidly Progressive Dysphagia

TL;DR

A woman with rapidly worsening swallowing difficulties was diagnosed with a rare severe form of myasthenia gravis after initial misdiagnosis.

Contribution

This case report highlights the diagnostic challenge of seronegative myasthenia gravis presenting with atypical dysphagia.

Findings

Rapidly progressive dysphagia can be an initial symptom of severe myasthenia gravis.

Seronegative myasthenia gravis can present without a clear etiologic factor.

Early recognition and treatment with plasmapheresis and immunomodulators led to clinical improvement.

Abstract

Dysphagia as the initial symptom of a severe myasthenic crisis is an atypical but well-documented presentation in the literature. A woman in her 40s presented to the emergency department with rapidly progressive dysphagia, initially misdiagnosed as gastro-oesophageal reflux. Two weeks earlier, she had completed eradication therapy for Helicobacter pylori. Within 24 hours of admission, she developed bulbar symptoms, dyspnoea, proximal muscle weakness, diplopia, and ptosis. Electromyography confirmed a neuromuscular junction disorder consistent with a myasthenic syndrome. Despite initiation of pyridostigmine, her condition deteriorated, requiring orotracheal intubation and intensive care. She received plasmapheresis, intravenous immunoglobulins, corticosteroids, and mycophenolate mofetil, with significant clinical improvement. The final diagnosis was severe, acute, seronegative myasthenia gravis without any clearly evident etiologic factor. This case highlights the importance of considering myasthenic crisis in the differential diagnosis of atypical dysphagia and acute respiratory failure with neurological signs, particularly in the emergency setting.

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