CN 2,3,5,8 Flashcards
CN2 Testing:
Using an ophthalmoscope:
From far:
Look for red light reflex
Close up:
-Optic disc
-dimple of Fovea
Test visual acuity:
13ft away from Snellen chart
Lesion:
Diabetic retinopathy
Hypertensive retinopathy
Aging -macular degeneration
Testing for:
Nearsightedness- far is blurry.
Farsightedness- close is blurry.
Astigmatism- oval cornea, blurry/stretched out images.
Presbyopia- age hardening lens.
Visual Fields:
Wiggle fingers peripherally - testing central (medial), peripheral (lateral).
Pituitary tumor causes- bitemporal hemianopia
Damage: d/t glaucoma, papilledema, scotoma(dark blind spot)
Blink to threat:
CN2 input, CN7 response by blinking.
Blind spot:
Enlarged- “Papilloedema”=ICP
When and why:
Patient complains of (diplopia, headaches, migraines, dizziness)
KBS Grading system:Hypertension
1) Silver wiring=arterial constriction
2) AV Nicking=irregular location, enlarged arteries
3) Cotton wool spots
4) Papilledema
Conditions that affect CN2:
-Diabetes
-MS
-Tumors
-SLE
-Syphilis
CN3 testing:
Pupillary Reflex:
- normal: 3mm diameter adult, >3mm in children and <3mm in elderly.
-Direct- pupil contracts directly to light
-Consensual/Indirect- shine light in left eye and right constricts.
-Swinging- checking if pupil constricts the same.
Near test:(Accommodation-the ability to see up close by changing the shape of the lens).
- ask patient to look at thumb, then at clinician, checking for for bilateral pupillary constriction.
Adie’s Pupil:
-one of the pupils is larger than other.
-Accommodation is slow and causes blurred vision.
-F>M, 50% resolve within 2 years.
Cover-uncover test:
-uncovered eye should constrict to adjust covered eye.
Ptosis:
Levator palpabrae superioris- only or Mullers( top and bottom eyelid affected)
Causes- Palsy of CN3 or Horners (small pupil as well)
Saccade= Quickly jerking movements-from frontal eye fields
Pursuit=eyes/pupils should smoothly follow finger
Vestibulocochlear reflex- passively move head up/down, L/R and eyes should follow all responses.
Nystagmus
Trauma, suspect diabetes, or hx of chronic hypertension.
CN3 palsy without pupil constriction is a sign of?
Diabetes
CN5 testing
Soft and pinprick:
-Over 3 branches
Temperature:
-Over 3 branches
Corneal reflex:
If neither blink- CN5
If Unilateral-CN7
Motor:
Resisted- open and close mouth, L/R movement for pterygoids.
Tensor tympani-> hyperacusis
Jerk reflex: jaw is relaxed/slightly open with tongue behind teeth
-UMNL suspected if jaw snaps shut
Trigeminal neuralgia:
-If patient young think MS
CN8 testing vestibular:
Vestibular:
Dix-Halpike- patient folds harms, turns head 45° towards clinician, the lie the patient down quickly until their head is at 20° degrees of extension from the bench. Nystagmus should appear within 20sec.
Epleys- performed after Dix-Halpike with patient still supine with head 20° extension and 45° lat. rot.- ask patient to roll over to the side the head is facing accompanied with head turning into 90°-> slowly let them get up from side posture whilst holding the head-> final position should be seated with chin tucked
CN8 testing cochlear:
Check for wax, blood or foreign bodies with the otoscope!
Conductive:
-Rub fingers near ear/whisper
-tuning fork near ear
Sensorineural:
-tuning fork near the ear
- bone conduction with tuning fork on mastoid.
Rinne test: +ve if normal
-tuning fork is placed on the mastoid
- if still able to hear=normal
-if both lost=sensorineural
Webber test:
-place tuning fork in the middle of the head.
-Conductive hearing loss= louder in affected ear
-Sensorineural hearing loss = louder in non affected ear
Bing test:
- tuning fork is on mastoid and patient occludes ear. This can differentiate conductive from sensorineural
CN8 Positive test meaning:
-Balance issues: BPPV
-Balance and hearing abnormal: Acoustic neuroma (causes vertigo and sensorineural loss)
-Conductive hearing loss: Wax, otosclerosis(surfers ear), otitis externa.
-Sensorineural hearing loss: menieres( overproduction of endolymph in the ear), vestibular
Shwannoma, meningitis
