====== Oculomotor nerve palsy ======


The primary symptom of [[oculomotor nerve]] palsy is [[diplopia]] from misalignment of the visual axes, and the pattern of image separation is the key to diagnosing which particular cranial nerve (and extraocular muscle) is involved. With unilateral [[third cranial nerve palsy]], the involved eye usually is deviated down and out (infraducted, abducted), and there is ptosis, which may be severe enough to cover the pupil. In addition, pupillary dilatation can cause symptomatic glare in bright light (if the ptotic lid does not cover the pupil), and paralysis of accommodation causes blurred vision for near objects.

===== Classification =====

[[Unilateral oculomotor nerve palsy]]

[[Non-pupil-sparing oculomotor palsy]]

Pupil sparing oculomotor palsy (pupil reacts to light)

===== Etiology =====

see [[Oculomotor nerve palsy etiology]].


===== Differential diagnosis =====

The differential diagnosis includes [[intracranial hemorrhage]], [[subarachnoid hemorrhage]], [[bacterial meningitis]], [[cavernous sinus thrombosis]], and [[midbrain]] [[infarction]].

[[Pituitary apoplexy oculomotor nerve palsy]], should be considered early in the differential diagnosis of sudden onset isolated complete third nerve palsy.

====Case reports====
A cervicocephalic [[fibromuscular dysplasia]] (FMD) patient with a history of right [[oculomotor nerve palsy]] in 2000. [[Angiography]] revealed bilateral [[internal carotid artery (aneurysm]]s and a [[fusiform aneurysm]] in the right [[vertebral artery]]. Typical "string-of-beads" phenomenon was observed in V2 segment of left vertebral artery. The right ICA [[giant aneurysm]] was treated by right ICA occlusion and [[superficial temporal artery to middle cerebral artery bypass]] at that time. Five years later, the patient presented with paroxysmal weakness in right limbs. The subsequent angiography showed the enlargement of left ICA aneurysm. It was treated satisfactorily with left external carotid artery-saphenous vein-MCA bypass and left ICA ligation. During the long-term follow-up, the patient kept no neurological deficit and the angiography showed good patency of bilateral grafts and the lesions in bilateral vertebral arteries remained unchanged
((Ma Y, Li M, Zhang H, Ling F. A 10-year follow-up of extracranial-intracranial 
bypass for the treatment of bilateral giant internal carotid artery aneurysms in 
a patient with fibromuscular dysplasia: case report. Acta Neurochir (Wien). 2010 
Dec;152(12):2191-5. doi: 10.1007/s00701-010-0778-3. Epub 2010 Aug 24. PubMed
PMID: 20734090.
)).