View source for Posterior Communicating Artery (PCOM) Aneurysm

==Background==
*Acute [[CN III palsy]] with ipsilateral pupil dilation is PCOM aneurysm until proven otherwise
**Aneurysm compresses the outer fibers (pupillomotor) of CN III → dilation
**In contrast to CN III palsy due to diabetes mellitus or hypertension in which pupil is spared

==Clinical Features==
*Inhibition of ipsilateral medial gaze, upward gaze, downward gaze, ptosis
**Lateral gaze (abduction) is preserved
*Ipsilateral dilated pupil

==Differential Diagnosis==
===Binocular Diplopia===
*Basilar Artery Thrombosis
*[[Posterior Communicating Artery (PCOM) Aneurysm|Posterior communicating artery (PCOM) aneurysm]]
*[[vertebral and carotid artery dissection|Vertebral artery dissection]]
*[[Myasthenia Gravis]]<ref>Kusner LL, Puwanant A, Kaminski HJ: Ocular myasthenia: Diagnosis, treatment, and pathogenesis. Neurologist 2006; 12:231-239</ref>
*[[Lambert-Eaton Myasthenic Syndrome |Lambert-Eaton Syndrome]]
*[[Botulism]]
*[[Cavernous sinus thrombosis]]
*[[Intracranial mass]], brainstem mass
*Miller Fischer variant [[Guillain-Barre]]<ref>Bushra JS: Miller Fisher syndrome: An uncommon acute neuropathy. J Emerg Med 2000; 18:427-430</ref>
*[[Multiple Sclerosis (MS)| MS]]
*[[Hyperthyroidism | Hyperthyroid]] Proptosis
*Basilar [[Meningitis]]
*[[Stroke (Main) |CVA]]
*Muscular Entrapment from [[Maxillofacial Trauma |Trauma]]
*[[Third nerve palsy]]

==Evaluation==

==Management==
*Emergent [[antihypertensives|BP reduction]] if hypertensive
*Neuroimaging
*Neurosurgical consult

==Disposition==

==References==
<references/>
[[Category:Neurology]]
[[Category:Vascular]]