Early parkinsonism masquerading as ocular myasthenia gravis

Numerous articles in the literature have reported cases of Parkinson's disease and myasthenia gravis (MG) occurring concurrently in the same patient. Here, we present a female patient in her late 60s diagnosed with ocular MG due to right eye ptosis and diplopia and treated with oral neostigmine. However, her right pupil was 5 mm in size and unresponsive to light, a finding atypical for MG. Further laboratory investigations for MG revealed negative results. On further physical examination, we noted mild rigidity, slight bradykinesia and slight tremors, raising the suspicion of early parkinsonism. A 99mTc-TRODAT Brain SPECT/MRI hybrid fusion study revealed features suggestive of early parkinsonism. Consequently, she was managed appropriately for parkinsonism. This case represents a unique presentation of early parkinsonism with ocular features, highlighting the importance of thorough differential diagnosis in complex presentations.