Third nerve palasy

Third nerve palsy

Features - eye is deviated 'down and out' ptosis - pupil may be dilated (sometimes called a 'surgical' third nerve palsy)

Causes - diabetes mellitus - vasculitis e.g. temporal arteritis, SLE false localizing sign* due to uncal herniation through tentorium if raised ICP - posterior communicating artery aneurysm - pupil dilated - often associated pain - cavernous sinus thrombosis - Weber's syndrome: ipsilateral third nerve palsy with contralateral hemiplegia -caused by midbrain strokes - other possible causes: amyloid, multiple sclerosis

*this term is usually associated with sixth nerve palsies but it may be used for a variety of neurological presentations