Transcript Sam Davies - Cranial Nerve Examination_1x

Wessex LMC Masterclass
Cranial Nerve
Examination
Dr Sam Davies, GP Locum
Aims
 Clinical examination demo
 Individual nerve functions
 Clinical scenarios/cases
 Questions
Mnemonics
 Oooh Oooh Ooooh To Touch And Feel Very Good
Velvet. Such Heaven!
 Some Say Marry Money But My Brother Says Big
Brains Matter More!
Cranial Nerves
 I: Olfactory
 II: Optic (acuity, visual fields, pupils, ophthalmoscopy)
 III: Oculomotor (superior and inferior)
 IV: Trochlear (superior oblique) – “SO4”
 V: Trigeminal (3 branches)
 VI: Abducens (lateral rectus) – “LR6”
Cranial Nerves
 VII: Facial
 VIII: Vestibulocochlear
 IX: Glossopharyngeal
 X: Vagus
 XI: Spinal Accessory
 XII: Hypoglossal
The Examination
 Demo!
I: Olfactory
 Sensory: smell
 Test each nostril individually
 Pathology: trauma
 meningitis
 frontal lobe disease/tumour
II: Optic
 Acuity: Snellen Chart
 Visual fields: detailed examination
 Pupil responses
 Ophthalmoscopy to assess optic disc
Visual field defects
http://interestingmedical.com/visual-field-defects/
Causes of a non-reactive
pupil?
Non-reactive pupil
 Acute angle-closure glaucoma
 Encephalitis
 Drug reaction
 Ocular trauma
 Opiates
 Uveitis
http://www.mcleishoptometrists.com/information/further-information/eye-problems/pupilproblems/
 Wernicke’s disease
III: Oculomotor
 Motor: all movements apart from superior oblique and
lateral rectus
 CN III lesion results in ptosis
 The eye moves “down and out”
 Dilated pupil due to unopposed sympathetic nerve
input
http://www.slideshare.net/hytham_nafady/oculomotor-nerve-35361054
IV: Trochlear
 Motor: supplies the superior oblique muscle
 “SO4”
 Responsible for depression and adduction of the eye
(down and in)
 Patient may report diplopia/double vision on looking
down and in  compensatory head tilt
V: Trigeminal
 Sensory: corneal reflex
 face (3 divisions: ophthalmic, maxillary, mandibular)
 Motor: muscles of mastication (masseter, frontalis,
pterygoids)
Corneal Reflex
 https://www.youtube.com/watch?v=x4UrvhaetdE
Sensory function of CN V
http://medical-dictionary.thefreedictionary.com/trigeminal+nerve
Motor function of CN V
 Chewing!
 Palsy  deviation to the side of
the lesion, open jaw
 Sensory loss: trigeminal
neuralgia, herpes zoster,
nasopharyngeal carcinoma
 Motor loss: bulbar palsy,
acoustic neuroma
https://quizlet.com/97749796/neuro-ii-flash-cards/
VI: Abducens
 Motor: controls lateral rectus (pulls eye out)
 “LR6”
 Palsy results in an inability to look laterally
 Also may have convergent strabismus
 Most common isolated ocular nerve palsy
Abducens nerve palsy
 Vasculopathic (DM, HTN, atherosclerosis), trauma,
idiopathic (25%)
 Less commonly: raised ICP, MS, sarcoidosis, vasculitis,
SOL, stroke, giant cell arteritis, Wernicke’s
http://www.rcemlearning.co.uk/modules/cranial-nerves-one-to-six/abducens-nerve-vi/introduction/
VII: Facial
 Motor: muscles of facial expression
 Sensory: taste to anterior 2/3 of tongue
 Test voluntary facial movements:





Wrinkling brow
Showing teeth
Frowning
Closing eyes tightly
Pursing lips
Puffing out cheeks
Facial Nerve Palsy
LMN lesion: one side of
face affected
•
•
•
•
•
•
•
Bell’s palsy
Polio
Otitis media
Skull fracture
Cerebellopontine angle tumour
Parotid tumours
Herpes Zoster  Ramsay Hunt
syndrome
UMN lesion: lower 2/3 of
face affected only
• Stroke
• Tumour
VIII: Vestibulocochlear
 Auditory
 Vestibular function: Balance (Rhomberg’s Test)
 Nystagmus
 Pathology: noise, labyrinthine problem, Meniere’s
disease, acoustic neuroma, brainstem CVA, drugs
IX and X: Glossopharyngeal
and Vagus
 Sensory: taste to posterior 1/3 of tongue
 Motor: controls swallow, gag reflex and voice
 Pathology: trauma, brainstem lesions, neck tumours
XI: Spinal Accessory
 Motor: supplies trapezius and sternocleidomastoid
muscles
 Test: shrug shoulders against resistance
 turn head to R/L against resistance
 Pathology is rare: Polio, trauma, bulbar palsy, local
lymphadenopathy
What does this slide show?
https://surgicaleducation.wordpress.com/2010/07/18/iatrogenic-nerve-palsy/
Finally… XII: Hypoglossal!
 Motor function to tongue
 Ask patient to stick tongue out
 If palsy present will deviate toward side of lesion
 Pathology: trauma, brainstem lesions, neck tumours
Case 1
• Jim, 34 years old, presents to duty
team
• Usually fit and well
• Recent viral URTI
• Woke this morning looking like this
• Reports facial numbness and
altered taste
• What is the diagnosis?
• How might you treat this?
http://medicalpicturesinfo.com
Bell’s Palsy
https://www.researchgate.net/figure/259808463_fig2_Drawing-representing-a-man-with-Bell'spalsy-showing-right-facial-hemiparalysis
Bell’s Palsy
 LMN/facial palsy - unilateral
 Peak age 10 - 40 years, M = F, 1 in 60 during lifetime
 Eyebrow droops, brown wrinkles smoothed out
 Impossible to frown or raise eyebrows
 Sudden-onset, sometimes post-auricular pain +/- facial
numbness +/- hyperacusis +/- watery eye
 Tx: 80% sponataneously improve. High-dose
prednisolone and aciclovir (if < 72 hours)
IMPORTANT!
 Bell’s Palsy = LMN lesion
 Ability to wrinkle brow is lost
 In UMN palsy, ability to wrinkle brow is preserved
 Full neurological examination including cranial nerves
is therefore essential
Case 2
•
•
•
•
•
•
•
•
Sarah, 51 years old
Known HTN, on ramipril 5mg OD
Otherwise fit and well
2/52 intermittent burning pain to L
mandibular region
Well between episodes
Exacerbated by talking or laughing
What is your differential?
What might you do next?
Trigeminal Neuralgia
http://www.cohenkayedental.com/pages/whatWeDo/orofacial/trigeminalNeuralgia.htm
Trigeminal Neuralgia
 Paroxysms of burning/stabbing/”electric shock”
 96% unilateral
 Mandibular/maxillary > ophthalmic
 F > M, more common > 50 years old
 Cause unclear, more common in MS or those with HTN
 Tx: carbamazepine
 Refer if < 50 years old or unable to control symptoms
Is This Physician Really So
Cool…
 Inspection
 Tone
 Power
 Reflexes
 Sensation
 Co-ordination
Summary
 Takes some practice!
 Important in helping formulate a differential
 Low threshold for referral/2nd opinion
 Systematic approach
 Questions…