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E-ISSN 2454-2784 Major Review A Comprehensive Review on the Management of III Nerve Palsy Anita Ganger, Shikha Yadav, Archita Singh, Rohit Saxena Squint and Neuro Ophthalmology Services, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India Abstract or signs helps in localizing the site of lesion and planning The third cranial nerve is a motor nerve chiefly involved in execution appropriate management. of movements of the eye. The paresis or paralysis of the one or more The search of published literature for this review article had of these muscles due to oculomotor nerve palsy, leads to ptosis, been completed using Ovid, Medline, Embase, Pubmed anisocoria and ocular motility defects. This article highlights the over the last 5 decades along with the checking of cross origin and course from nuclear level to terminal branches along with references also. English language articles with full text associated clinical symptoms and signs that help in localizing the site access were included and electronic literature search was of lesion and planning appropriate management. performed using oculomotor nerve, palsy and management Keywords: oculomotor nerve, paralysis, management as key words. While reviewing the literature, parameters evaluated were applied neuroanatomy, related syndromes, Introduction medical management and surgical management modalities The third cranial nerve is a motor nerve chiefly involved for oculomotor nerve palsy. in execution of movements of the eye. Also known as the oculomotor nerve, it supplies all the extraocular muscles Applied Neuro-Anatomy except for lateral rectus and superior oblique. Thus it helps Nuclear Complex - The location of nuclear complex of the in carrying out the extraocular movements efficiently third nerve is in the midbrain at the level of the superior improving the binocular field of vision. The chief muscles colliculus ventral to the Aqueduct of Sylvius, the right and being supplied by the third nerve are the Superior Rectus, left components straddling the midsagittal plane.3,4 The Inferior Rectus, Medial Rectus and Inferior Oblique which central caudal nucleus (unpaired) in the midline innervates are responsible for the elevation, depression, adduction and both the right and left levator palpebrae muscles. Thus extorsion of the eye respectively. In addition, the ciliary lesion at this level results in bilateral ptosis. The superior muscle and the sphincter pupillae are supplied by the rectus fascicles decussate within the nuclear complex and parasympathetic fibres from the Edinger-Westphal nucleus innervate the contralateral superior rectus. The medial and are responsible for the accommodation and pupillary rectus, inferior rectus and inferior oblique muscles and the constriction. The levator palpebrae superioris (LPS) which parasympathetic pathways are supplied by the ipsilateral elevates the eyelid is also supplied by the oculomotor nerve. subnuclei which are paired. Caudal nuclear lesions may The paresis or paralysis of the one or more of these muscles spare the pupil and rostral lesions may present without causes ptosis, anisocoria and ocular motility defects. The ptosis. Lesions involving the nucleus, due to infarction, unopposed action of the lateral rectus and superior oblique demyelination, inflammation, primary tumours or muscles results in fixed eye in a down and out position in metastasis are uncommon. cases with complete paralysis. Fasciculus - The fascicles travel ventrally through the The involvement of the third nerve could be congenital or tegmentum, passing through the red nucleus and the acquired in nature. The main causes of acquired third nerve medial aspect of the cerebral peduncles, emerge from palsy include: infections (CNS or local), trauma, direct or the midbrain and pass into the interpeduncular fossa. indirect compression of the nerve anywhere along its path, Fascicular involvement occurs in compressive lesions vascular conditions (ischemic/aneurysms), neoplastic, (primary tumor or metastasis), infarction, hemorrhage and 1,2 inflammatory or demyelinating diseases. It could be demyelinating diseases.5,6 Classically described midbrain complete or partial, pupil-sparing or involving, isolated syndromes arising out of lesions affecting the fasciculus are or associated with other neurological symptoms. Precise as mentioned in the Table 1. knowledge of its origin and course from nuclear level to terminal branches along with associated clinical symptoms Subarachnoid space (Basilar) - The rootlets emerge from the brainstem medial to the cerebral peduncle and unite to form the main trunk. This trunk traverses between the Access this article online posterior cerebral and superior cerebellar arteries passing Quick Response Code Website lateral to the posterior communicating artery along the base www.djo.org.in of the skull, in the subarachnoid space. Aneurysms arising at the junction of posterior communicating artery and middle cerebral arteries can affect the nerve by compression or acute DOI hemorrhage resulting in acute painful ophthalmoplegia. http://dx.doi.org/10.7869/djo.215 Lesions at this level typically result in isolated third nerve palsy. Involvement of nerve at this level may be idiopathic in 25% of the cases. Pupillomotor fibres lie superomedial in the periphery of the nerve making them prone to injury www.djo.org.in 86 Major Review Table 1: Showing classically described midbrain syndromes arising out of lesions affecting the fasciculus Syndrome Level of Lesion Features Weber Syndrome7 Cerebral peduncle Ipsilateral III nerve palsy + Contralateral hemiparesis Benedikt Syndrome7 Red Nucleus Ipsilateral III nerve palsy + Contralateral extrapyramidal signs Nothnagel Syndrome7 Fasciculus + Superior Ipsilateral III nerve palsy + Cerebellar Cerebral Peduncle Ataxia Claude Syndrome7 Combination of Benedikt and Nothnagel syndrome by external compression or trauma and are spared by the such as elevation of the eyelid during attempted adduction ischemic events.8 The downward herniation of the uncus (Inverse Duane syndrome) or depression (Pseudo-Von in the temporal lobe by extradural or subdural hematoma Graefe’s sign) or miosis in an otherwise non-reactive pupil caused by head trauma or an expanding supratentorial (Pseudo-Argyll-Robertson pupil). mass can stretch or compress the third nerve against the A patient with CN III dysfunction can present with doubling tentorial edge, initially causing irritative miosis followed of vision, drooping of upper eyelid, ocular pain, headache, by pupillary dilatation (Hutchinson’s pupil) and later total glare, monocular blurred vision, or any combination.16 oculomotor nerve palsy. “The rule of the pupil” suggests When a patient presents with acute onset of limitation of that if a compressive lesion causes a third nerve palsy, the movements in one eye, the categorization of the defect as chances of pupil involvement are 95-97%.9,10 In 32% cases of complete or partial with or without the involvement of ischemic lesions pupil involvement may be seen.11 the pupil is useful in coming to a diagnosis and further Cavernous sinus (Intracavernous) - The nerve lie in the evaluation. Isolated oculomotor nerve palsy is idiopathic in superolateral wall of the sinus along with fourth and the 25% of the cases and is commonly due to basilar lesions. first two divisions of the trigeminal nerve. Here it divides Pupil-sparing third nerve paresis in an elderly patient with into the superior and inferior divisions in the anterior part known systemic vascular disease can be considered to be of the sinus or at the superior orbital fissure passing into ischemic mono neuropathy, which is a common cause. the orbit through the annulus of Zinn. However, there is However the possibility of vascular inflammation such as evidence that the functional bifurcation of third nerve occurs giant cell arteritis should be kept in mind in elderly patient more proximally within the brainstem.12-14 Intracavernous and may be excluded by history, complete hemogram, involvement may be seen in cases of diabetes mellitus, erythrocyte sedimentation rate (ESR) and C-reactive protein pituitary apoplexy, aneurysmal dilatations, Tolosa hunt (CRP). These patients can be managed conservatively and syndrome, meningiomas, etc. reassessed after a week to rule out pupil-involvement or increase in pain. Weekly follow-ups initially followed by Orbit (Intra-orbital) - Innervation of the superior rectus and monthly evaluation are important to document recovery levator palpebrae muscles is by the superior division and and plan any intervention accordingly. Ischemic mono the inferior division innervates the medial rectus, inferior neuropathies usually start recovering by 8-12 weeks. rectus, inferioroblique and provides parasympathetic fibres Acute palsy in individuals less than 40 years of age suggests to the ciliary ganglion. These divisions then enters the need for neuroimaging and a complete neurological orbital apex through the superior orbital fissure, where they workup. travels with the optic nerve, ophthalmic artery, nerve VI, Common cause of isolated oculomotor nerve involvement is 15 and the nasociliary branch of V1. Orbital lesions are usually intracranial aneuryms. Therefore, its thorough evaluation is associated with visual impairment, proptosis and chemosis. a must.17,18 If a patient presents with sudden onset of severe Causes mentioned in literature are trauma, neoplasm, headache, meningismus and photophobia with oculomotor vascular malformation and inflammation.

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