Cranial Nerves PULSE Preparation for Finals Tutor name

Cranial Nerves PULSE: Preparation for Finals Tutor name

Tu. BS attendance • https: //tutorialbooking. com/

Session overview • Common cranial nerve conditions for the OSCE • How to present your findings • Summary of clinical signs • Case presentations and viva questions

What is the purpose of an OSCE? “This station tests a student’s ability to perform an appropriate focussed physical examination, demonstrating consideration for the patient, and to report back succinctly describing the relevant findings. It also tests a student’s clinical judgement i. e. the ability to decide the differential diagnosis, choose investigations and formulate a management plan. ”

Common cranial nerve conditions in the OSCE • It is highly unlikely you will be asked to examine ALL cranial nerves • Ophthalmoplegia • Field defects • Facial nerve palsy

Presenting your findings • What were you asked to do? • What were your key positive findings? • What were the important negative findings? • What does this mean? • How would you complete your examination, and what investigations would you do?

Example case presentation • I was asked to examine the cranial nerves of this elderly gentleman • On examination I found that he had a failure of lateral gaze in the left eye • All other eye movements were intact, visual acuity was normal, and there were no visual field defects • No abnormalities in the other cranial nerves were detected • This would be consistent with a diagnosis of a 6 th nerve palsy • To complete my examination I would like to perform fundoscopy and do a full neurological examination of the limbs – FURTHER TESTS

Completing your examination • Complete cranial nerves examination • Formal tests • • • 1: scents 2: Snellen and Ischiara charts 3, 4, 6: fundoscopy, corneal reflex 7: jaw jerk 9: gag reflex • Perform fundoscopy • Full neurological examination of the limbs

Investigations • Bloods; FBC, U&E, LFTs, glucose, B 12/folate • Imaging; CXR (paraneoplastic/ Horners), CT, MRI (posterior lesions, cord) • LP; cells, oligoclonal bands, xanthochromia • Other; nerve conduction studies

Clinical signs

Oculomotor nerve palsy CN III - Down and out - Ptosis - Fixed dilated pupil - Causes - vasculitic (DM, HTN) - aneurysm (PCAA) - Medical vs surgical - Medical: DM: pupil sparing - Surgical: fixed, dilated pupil - Parasympathetic fibres run along the periphery and are the first to be affected by compression

Why is the pupil spared in diabetic palsies?

Trochlear Cranial Nerve Palsy CN IV - Superior oblique - Head tilt - Vertical diplopia - Causes - vasculopathic - tumour - congenital - trauma

Abducens Palsy: CN VI - Unopposed action of medial rectus - Causes - Vasculopathic (DM, HTN) - Tumour - Intracranial pressure: false localising sign

Cranial Nerve Cases

Case 1

Examination of CN I-III • WINDEC • STAND BACK: observe +closely at eyes • CN III

Case 1 – CN I - III • Normal smell • Normal fields • Also impaired looking to far left – left eye essentially fixed, bulging from socket • Pupils non reactive to light

Case 1 – CN V onwards • Sensation – decreased in upper and mid face, normal in beard region • Facial movements otherwise normal • Tongue movements normal and symmetrical • Hearing intact. Renne +ve; Weber NAD • Normal cough and speech • No neck wasting or weakness Please present your findings.

Case 2

Case 2 - eyes • PERLA • Eye movements normal (? small amount of nystagmus) • Normal visual fields • Sensation reduced on right throughout

Case 2 – CN V onwards • Reduced facial movements on right, including right forehead • Partially deaf on right side – Rinne’s – air louder, Weber’s – left louder • Normal cough and voice • Tongue movements normal • No neck muscle wasting, no weakness • Bonus points – on walking, he falls to the right • Bonus bonus – past pointing Please present your findings.

Case 3

Case 3 Please present your findings.

What is Horner’s syndrome? • Horner’s Syndrome • = collection of signs: • unilateral pupillary constriction (miosis), • ptosis and • anhydrosis (i. e. loss of sympathetic pathway on that side).

What are the causes of Horner’s syndrome? • Hemisphere and brainstem • Massive cerebral infarction • Pontine glioma • Vascular disease (esp. lateral medullary syndrome – infarction of lateral medulla, due to occlusion of vertebral artery, posterior inferior cerebellar artery, superior, middle or inferior medullary arteries) • ‘Coning’ of the temporal lobe • T 1 root • Apical bronchial neoplasm (usually SCC) • Apical TB Cervical rib • Brachial plexus trauma or tumour Sympathetic chain in neck • Post thyroid/laryngeal surgery • Malignancy, e. g. thyroid; neoplastic infiltration • Cervical sympathectomy • Carotid artery • Occlusion/dissection • Pericarotid tumours (Raeder’s syndrome) • Cluster headache Cervical cord • Syringomyelia • Cord tumours • • • Miscellaneous • Congenital • Migrainous neuralgia (usually transient) • Isolated and unknown cause

Cranial nerve summary

Groups of nerve palsies • III and IV – midbrain nuclei • V, VII, VIII – pons nuclei • IX, X, XII – medulla nuclei • Unilateral III, IV, VI, Va – cavernous sinus lesion; superior orbital fissure lesion (Tolosa-Hunt syndrome) • Unilateral V, (VI), VIII, (IX) – cerebellopontine angle lesion (usually tumour) • Unilateral IX, X, XI – jugular foramen lesion • Eye and facial muscles, worse on exertion – myasthenia gravis • UMN IX, X, XII – pseudobulbar palsy • LMN IX, X, XII – bulbar palsy

Summary • Common cranial nerve conditions for the OSCE • How to present your findings • Summary of clinical signs • Case presentations and viva questions

Please complete Tu. BS feedback • Tutor details • For more information on Examining for Finals sessions: • examiningforfinals@gmail. com • www. sefce. net/pulse • Resource Updated 2017: Dr A Swan • With thanks to previous contributors: • Dr Emma Claire Phillips (FY 2) • Dr Kristina Lee (FY 2)