PACES - CN Flashcards
TEST CN I
Olfactory
Ask about change in smell, offer smelling salts
TEST CN II
Optic (AFRO)
Acuity - Snellen Chart, Ishihara Plates
Fields - 1m apart, no glasses. Neglect = Which finger is wiggling. Fields = 4 corners, bring wiggling finger in form outside FOV. Offer red pin central vision & blind spot
Reflexes - Inspect pupil size, shape, symmetry. Direct reflex (constrict with light). Consensual reflex (constrict with light in other eye). Swinging (RAPD). Accommodation, ask to look at wall then finger, assess for constriction.
Opthalmoscopy - Check red reflex and optic disk
TEST CN III
Oculomotor
Dipolopia/Pain on H movement pattern. Check for nystagmus.
Lesion = Down and out pupil, ptotsis, mydriasis
TEST CN IV
Trochlear
Diplopia/Pain on H movement pattern. Check for nystagmus
Lesion = Vertical diplopia when looking downwards
TEST CN VI
Abducens
Lesion = Convergent squint, Horizontal diplopia worse when looking towards the affected side
Convergent squint, Abducens palsy
CN III lesion
TEST CN V
Trigeminal
Motor - Clench teeth (masseter), Open jaw against resistance
Sensory - V1, V2, V3
Reflexes (Offer corneal), Jaw jerk
TEST CN VII
Facial
Motor - Can you raise your eyebrows, Scrunch your eyes, Puff cheeks out, show me your teeth.
TEST CNVIII
Vestibulochochlear
Whisper number in each ear, can you repeat. If no, offer Rinne’s and Weber’s and formal audiometry testing
TEST CN IX, X
Glossopharyngeal, Vagus
Voice quality
Say ahh, check for symmetry and deviation of uvula.
Offer to test gag reflex.
TEST CN XI
Accessory
Ask the pt to shrug their shoulders and turn their head to the side against resistance on the cheek
Test CN XII
Hypoglossal
Ask pt to stick tongue out.
Deviation/Fasciculations.
Press tongue against finger resting on cheek to assess motor
How would you test the jaw jerk reflex?
Ask the pt to open their mouth
Place finger horizontally across pt’s chin
Tap finger lightly with tendon hammer
Observe slight closing of jaw.
Hypoglossal nerve palsy (Left)
Bell’s Palsy
Ptosis
How does the swinging light test work?
Swing from eye to eye.
Light in normal eye = both constrict
Light in affected eye = Less constriction
= Marcus Gunn pupil = Relative Afferent Pupillary Defect = partial CN II lesion (can be seen in optic neuritis)
What can cause Horner’s Syndrome?
Central = MS, Syrigngeomyelia
Preganglionic = Pancoast tumour, Trauma from Central Venous Line insertion
Post-Ganglionic = Cavernous sinus thrombosis, carotid artery dissection
What might cause unequal pupils?
Horner’s
CN 3 palsy
Migraine
Drugs
What can cause an rapd?
MS
Glaucoma
What is an argyll-robertson pupil?
Small irregular pupil
Accommodate but not reactive to light
DM, Syphylis
What is a holmes-Adie pupil?
Dilated pupil with no response to light
Benign
What can cause a homonymous hemianopia?
SOL
MCA Stroke, with hemiparesis
PCA stroke, macula sparing and cerebellar signs
What can cause a bitemporal hemianopia
Chiasmatic Lesion
Check for endo disease
Muscles of the eyes?
Superior Rectus
Superior Oblique
Inferior Rectus
Inferior Oblique
Medial Rectus
Lateral Rectus
Superior + Inferior rectus = CN III
Lateral Rectus = CN VI
Superior Oblique = CN IV
Oculomotor Palsy
Ptosis, Down and out pupil, mydriasis, reduced direct and consensual constriction
Trochlear Palsy
Double vision when looking down
Abducens palsy
Generic causes of cn nerve lesions?
DM
HTN
MS
Raised ICP
Bell’s Palsy (CN VII)
Add ons to CN exam?
Full Neuro exam and history
Urine dip
Fundoscopy
EMG, Nerve conduction
MRI spine/Brain
