Pupil-sparing, painless compression of the oculomotor nerve by expanding basilar artery aneurysm: a case of ocular pseudomyasthenia.
BACKGROUND
Oculomotor nerve paresis may have relatively benign but also life-threatening causes. Distinguishing between these is of great clinical importance.


OBJECTIVE
To reveal a potential pitfall of the clinical evaluation of oculomotor nerve paresis.


METHODS
Single case observation.


RESULTS
A 56-year-old man had fluctuating diplopia and fatigable ptosis, promptly relieved by intravenous edrophonium, leading to the diagnosis of ocular myasthenia gravis. His pupillary function was intact. A few days after the initial diagnosis, he suffered a subarachnoid hemorrhage secondary to the rupture of a basilar artery aneurysm. His ocular symptoms were related to aneurysmal oculomotor nerve compression.


CONCLUSIONS
Patients with oculomotor nerve dysfunction need more detailed evaluation because the underlying cause cannot be safely determined on a clinical basis.
Ajtai
Bela
B
Department of Neurology, State University of New York at Buffalo, NY, USA. ajtaix@yahoo.com
Fine
Ed J
EJ
Lincoff
Norah
N
D017542:Aneurysm, Ruptured / Q000150:complications; D001763:Blepharoptosis / Q000209:etiology; D003937:Diagnosis, Differential; D004172:Diplopia / Q000209:etiology; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications* / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000473:pathology; D009408:Nerve Compression Syndromes / Q000209:etiology* / Q000503:physiopathology; D009802:Oculomotor Nerve / Q000473:pathology*; D010291:Paresis / Q000209:etiology; D011680:Pupil / Q000502:physiology*; D012422:Rupture, Spontaneous; D013345:Subarachnoid Hemorrhage / Q000209:etiology