Anti-Muscle Specific Kinase (Anti-MuSK) Positive Myasthenia Gravis Overlapping With Parkinson’s Disease: A Challenging Diagnosis

The concomitance between Parkinson’s disease (PD) and myasthenia gravis (MG) is rare, with only a few case reports in the literature and only one of them with positive anti-muscle specific kinase (anti-MuSK) MG. The overlap between PD and MG symptoms can cause a diagnostic dilemma for the treating physician. In this report, we present a 73-year-old lady with a history of recurrent falls, dysphagia, and diplopia. She was found to have ptosis, vertical gaze restriction, neck extension, and flexion weakness, as well as features of parkinsonism, including masked face appearance, asymmetrical limbs rigidity, and bradykinesia. She was found to have a high titer antibody for MuSK MG. Her MG symptoms were treated successfully with rituximab.