Atypical Bulbar Myasthenia Gravis in an Elderly Male Unmasked by Levofloxacin: A Diagnostic Challenge.

BACKGROUND

Myasthenia gravis (MG) is an autoimmune neuromuscular disorder that typically presents with ocular symptoms. Isolated bulbar symptoms, such as dysphagia and dysarthria, are rare, and most commonly seen in men with late-onset MG. We report one such rare case of MG in an 82-year-old male presenting with progressive bulbar weakness, seemingly triggered by levofloxacin use.

CASE REPORT

An 82-year-old male with multiple comorbidities presented with progressive weakness, dysphagia, and drooling following levofloxacin therapy. Examination revealed neck drop, weak lower facial muscles, and dysarthria. Initial neuroimaging and labs were inconclusive. Neurology initiated pyridostigmine with rapid improvement. Elevated acetylcholine receptor antibodies confirmed MG. He was started on efgartigimod alfa in the outpatient setting with improvement in MG composite scores.

CONCLUSIONS

Atypical bulbar MG can mimic other neurologic disorders and is prone to delayed diagnosis, especially in the elderly. Clinicians should maintain a high index of suspicion, particularly when symptoms worsen after medication exposures like fluoroquinolones. Early diagnosis and appropriate treatment can significantly improve outcomes and quality of life.

LEARNING POINTS

Levofloxacin can exacerbate or unmask myasthenia gravis.