3rd nerve palsy

Brief discussion on Oculomotor nerve palsy

1. Dr Md Ferdous Islam FCPS Part 2 Trainee Dept of Ophthalmology CMH, Dhaka 3 rd Cranial Nerve Palsy

2. 3rd cranial nerve OCULOMOTOR NERVE Entirely motor in function Supplies – All the Extraocular muscles except superior oblique and lateral rectus Levator palpebrae superioris Intra ocular muscles- Sphincter pupillae and cilliary muscle

3. Nucleus Located in midbrain at the level of superior colliculus , ventral to the Sylvian aquiduct . Composed of Unpaired levator subnucleus Paired superior rectus sub nuclei Paired medial rectus, inferior rectus and inferior oblique subnuclei

4. Course Can be divided into – Fascicular Basilar Intracavernous Intraorbital part

5. Course

6. Intracavernous portion of 3rd nerve

7. Intraorbital portion of 3rd nerve

8. Major causes of nuclear complex lesion of 3rd nerve palsy Vascular occlusion – Diabetes & Hypertension Neoplastic lesions – primary tumour or metastasis Haemorrhage

9. Major causes of fascicular lesion of 3rd nerve palsy Vascular occlusion – Diabetes & Hypertension Neoplastic lesions – primary tumour or metastasis Haemorrhage Demyelination

10. Syndromes of Fascicular lesion Benedikt syndrome- Ipsilateral 3rd nerve palsy and contralateral extrapyramidal signs Weber syndrome- Ipsilateral 3rd nerve palsy and contralateral hemiparesis Nothnagel syndrome- Ipsilateral 3rd nerve palsy and cerebellar ataxia Claude syndrome

11. Major causes of lesion in Basilar region The 3rd nerve traverses the basilar part unaccompanied by any other cranial nerves. Isolated 3rd nerve palsies are commonly basilar. The important causes are Aneurysm Head trauma-Extradural or subdural haematoma

12. Major causes of Intracavernous lesion Usually associated with involvement of 4th, 6th nerves & first division of 5th nerve. Diabetes – causes pupil sparing 3rd nerve palsy Pituitary apoplexy Others – Aneurysm, Meningeoma , Carotid-cavernous fistula .

13. Intraorbital causes of 3rd nerve palsy Trauma Vascular Neoplasm Inflammation

14. Pupillomotor fibers Parasympathetic fibers Located superficially between the brainstem and the cavernous sinus Blood supply derived from the pial blood vessels Main trunk of 3rd nerve supplied by the vasa nervorum

15. Causes of isolated 3rd nerve palsy Idiopathic – about 25% Vascular – Hypertension & Diabetes (commonly pupil sparing) Aneurysm – posterior communicating artery at its junction with internal carotid artery Trauma – subdural haematoma with uncal herniation Miscellaneous

16. Clinical features of total 3rd nerve palsy SYMPTOMS Drooping of eyelid Binocular double vision Pain (may be present)

17. SIGNS Ptosis Abduction of globe Intortion of the globe which increases on attempted down gaze Limitation of adduction Limitation of elevation Limitation of depression Dilated pupil with defective accommodation

18. History of Patient Onset Duration Diplopia Trauma Associated systemic disorders

19. Examination Pupillary reactions Motility restrictions Ptosis Other cranial nerves

20. Investigations

21. Investigations

22. Treatment Non-surgical Treatment of underlying cause Diplopia – Occlusion patch or prism in involved eye Monitor children for development of amblyopia Surgical Neurosurgery – Aneurysm or haematoma Strabismus or ptosis surgery – Not earlier than 6 months from time of onset

23. Follow-up Pupil sparing – Observe daily for 5 days for pupil involvement Recheck every 4 to 6 weeks If secondary to ischemia function usually returns within 3 months

24. Differential Diagnosis Myasthenia gravis Thyroid associated orbitopathy Chronic progressive external ophthalmoplegia Idiopathic orbital inflammatory disease

25. Thank You