Disorders of cranial nerves

Question 1

Clinical tests used to assess CN II (think examination) (5)

Answer 1

Visual acuity – Snellen test
Visual field test
Pupillary reflex
Fundoscopy
Colour vision test

Question 2

Clinical test used to assess CN III, IV, VI

Answer 2

Eye movements - follow finger as it makes a H shape

Question 3

What are we looking for when testing CN III, IV, VI (4)

Answer 3

Evidence of ptosis
Evidence of anisocoria (unequal pupils)
Pupillary reactions
Diplopia

Question 4

Clinical tests used to assess CN V (4)

Answer 4

Sensation (light and heavy touch) in the ophthalmic, maxillary and mandibular areas
Power of the muscles of mastication (masseter and pterygoids)
Corneal reflex
Jaw jerk reflex

Question 5

Clinical tests used to assess CN VII (3)

Answer 5

Movements of the muscles of facial expression

• Raise eyebrows/wrinkle forehead
• Squeeze eyes
• Smile with teeth
• Puff cheeks

Corneal reflex

Taste

Question 6

Clinical tests used to assess CN VIII (5)

Answer 6

Hearing tests

• Whisper test
• Rinne’s test
• Weber’s test

Balance

• Dix-hallpike maoeuvre
• Untenberger’s test

Question 7

Clinical tests used to assess CN IX & X (4)

Answer 7

Movement of the palate – symmetrical/asymmetrical
Gag reflex
Quality of speech – if poor, indicates weakness at back of palate
Quality of cough

Question 8

Clinical tests used to assess CN XI (2)

Answer 8

Head turning - SCM

Shoulder shrugging - trapezius

Question 9

Clinical tests used to assess CN XII (2)

Answer 9

Appearance of tongue - fasciculations, wasting

Movement and power of tongue

Question 10

What cranial nerve is the afferent and efferent of the pupillary light reflex

Answer 10

Afferent - CN II

Efferent - CN III

Question 11

What cranial nerve is the afferent and efferent of the corneal reflex

Answer 11

Afferent – CN V

Efferent – CN VII

Question 12

What cranial nerve is the afferent and efferent of the jaw jerk reflex

Answer 12

Afferent & efferent - CN V

Question 13

What cranial nerve is the afferent and efferent of the gag reflex

Answer 13

Afferent – IX

Efferent - X

Question 14

Where is the nuclei of CN III & IV

Answer 14

Midbrain

Question 15

Where is the nuclei of CN V, VI & VII

Answer 15

Pons

Question 16

Where is the nuclei of CN VIII

Answer 16

Pontomedullary junction

Question 17

Where is the nuclei of CN IX, X, XI & XII

Answer 17

Medulla

Question 18

What is the angle called where CN VI & VIII emerge

Answer 18

Cerebellopontine angle

Question 19

Pure motor signs sometimes may not actually be a cranial nerve lesion but indicate the pure motor disease:

Answer 19

Myasthenia gravis

Question 20

Which of the following is an appropriate method of testing coordination of the lower limb:

A Ask the patient to state if his toe is moved up or down, when his eyes are shut

B Assessing the patient’s ability to sit up from lying

C Assessing the plantar response

D Finger-nose test

E Heel-shin test

Answer 20

E

Question 21

A 51 year old man is noted to have a left trigeminal nerve palsy.

Which of the following is the most likely examination finding:

He has absent taste sensation to the anterior two thirds of the left of the tongue

B He has numbness over the left mandible

C He has numbness over the right maxilla

D He has numbness over the right posterior aspect of the scalp

E He is unable to smile with the left side of his mouth

Answer 21

B

Question 22

Clinical features of optic neuritis (7)

Answer 22

Monocular visual loss
Pain on eye movement (as nerve inflamed)
Peri-orbital pain
Reduced visual acuity/ blurry
Reduced colour vision

Optic disc swollen - papilloedema
Relative afferent pupillary defect

Question 23

General trigger of trigeminal neuralgia (a type of headache)

Answer 23

Temperature

Question 24

Clinical features of Bell’s palsy (4)

Answer 24

Unilateral facial weakness
Dry eye - due to inadequate blinking
Post-auricular pain
Synkinesis - involuntary muscular movements accompanying voluntary movements, e.g. voluntary smiling may induce an involuntary contraction of the eye muscles

Question 25

Bell's palsy is thought to be due to what

Answer 25

Re-activation of herpes simplex virus

Question 26

Treatment of Bell's palsy (2)

Answer 26

High dose steroids Eye protection - daytime (glasses, artificial tears); Overnight (ophthalmic lubricant, eyelid taped)

Question 27

In UMN facial paralysis, is the forehead preserved

Answer 27

Yes, forehead unaffected unlike LMN facial paralysis

Question 28

Clinical features of vestibular neuronitis (inflamed vestibular branch of CN VIII) (3)

Answer 28

Disabling vertigo Vomiting Nystagmus

Question 29

Vestibular neuronitis thought to be due to what

Answer 29

Preceding viral infection

Question 30

Effect of sympathetic system on pupils

Answer 30

Dilates pupils

Question 31

Effect of parasympathetic system on pupils

Answer 31

Constricts pupils

Question 32

Palsy of what CN leads to a fixed dilated eye

Answer 32

CN III

Question 33

Causes of DILATED pupils (7)

Answer 33

``` Youth Dim lighting Anxiety, excitement “Mydriatic” eye drops Amphetamine, cocaine overdose CN III palsy Brain death – bilateral dilated ```

Question 34

Causes of CONSTRICTED pupils (5)

Answer 34

``` Old age Bright light “Miotic” eye drops Opiate overdose Horner’s Syndrome – small pupil unilaterally ```

Question 35

Causes of isolated CN III palsy - microvascular causes (2) - compressive cause (2)

Answer 35

Microvascular causes - Diabetes - Hypertension Compressive cause - posterior communicating artery aneurysm - raised ICP

Question 36

Clinical features of microvascular causes v compressive causes of CN III palsy

Answer 36

Microvascular causes – PAINLESS, PUPIL UNAFFECTED, NO HEADACHE Compressive causes – PAINFUL, PUPIL AFFECTED

Question 37

Common cause of isolated CN IV palsy

Answer 37

Diabetes

Question 38

Causes of isolated CN VI palsy (4)

Answer 38

Idiopathic Diabetes Meningitis Raised ICP

Question 39

Causes of nystagmus (6)

Answer 39

``` Congenital Serious visual impairment Peripheral vestibular problem Central vestibular problem/ brainstem disease Cerebellar disease Toxins – medication ```

Question 40

What is bulbar palsy (LMN or UMN, affecting what CNs)

Answer 40

LMN PROBLEM (bilateral LMN lesions affecting CN IX-XII – e.g. MND (motor neurone disease), polio, tumours, syphilis)

Question 41

What is pseudo bulbar palsy (UMN or LMN)

Answer 41

Bilateral UMN lesions - e.g. lesion of internal capsule, MND (motor neurone disease))

Question 42

Clinical features of bulbar palsy (4)

Answer 42

Wasted fasiculating tongue Dysarthria Dysphonia Dysphagia

Question 43

Clinical features of pseudobulbar palsy (6)

Answer 43

``` Dysarthria Dysphonia – loss of speech volume Dysphagia Spastic, immobile tongue Brisk jaw jerk Brisk gag reflex ```