Lecture 35 Disorders of the Cranial Nerve

Question 1

Name the cranial nerves involved in special sensory function

Answer 1

• Olfaction (I)
• Vision (II)
• Taste (VII, IX and X)
• Hearing - and balance (VIII)

Question 2

Name the cranial nerves involved in general sensation

Answer 2

• Trigeminal Nerve V3
• The ear from the VII (facial)
• IX (glossopharyngeal)

Question 3

Name the cranial nerves involved in control of muscle activity

Answer 3

• Eye muscles – III (oculomotor), IV (trochlear) and VI (abducence) (LR6,SO4, rest 3)
• Muscles of mastication – V3 (trigeminal)
• Muscles of facial expression – VII (facial)
• Muscles of larynx and pharynx – mainly X (vagus)
• Sternomastoid and trapezius muscles - XI (accessory)

Question 4

Name the cranial nerves that are parasympathetic and involved with autonomic functions

Answer 4

• Pupillary constriction – III (oculomotor)
• Lacrimation – VII (facial)
• Salivation – submandibular and sublingual glands – VII (facial)
• Salivation – parotid gland - IX (glossopharyngeal)
• Vagal (X) input to organs in thorax and abdomen

Question 5

How would you test Olfactory nerve

Answer 5

Smell-unilateral or bilateral loss

Question 6

How would you test Optic nerve

Answer 6

visual acuity, visual fields, pupillary reactions, fundoscopy, colour vision

Question 7

How would you test the oculomotor, trochlear and abducens nerve

Answer 7

ptosis, pupil of equal size, pupillary reactions, eye movements

Question 8

How would you test the trigeminal nerve

Answer 8

power in the muscles of mastication, corneal reflex, jaw jerk

Question 9

How would you test the facial nerve

Answer 9

muscle of fascial expression, corneal reflex, taste

Question 10

How would you test the vetsibulochlear nerve

Answer 10

hearing using Rinne’s and Weber’s tests, Vestibular function using Dix-Hallpike manoeuvre and Untenberger’s test

Question 11

How would you test the glossopharyngeal nerve

Answer 11

movement of palate, gag reflex, quality of speech, quality of cough

Question 12

How would you test the accessory nerve

Answer 12

• head turning and shoulder shrugging

Question 13

How would you test the hypoglossal nerve

Answer 13

appearance, movement and power of tongue

Question 14

Name the afferent and efferent nerves involved in pupillary reflex

Answer 14

afferent – II ; efferent – III

Question 15

Name the afferent and efferent nerves involved in corneal reflex

Answer 15

afferent – V ; efferent – VII

Question 16

Name the afferent and efferent nerves involved in Jaw jerk

Answer 16

V

Question 17

Name the afferent and efferent nerves involved in gag reflex

Answer 17

• afferent – IX ; efferent - X

Question 18

Where is the oculomotor and trochlear located

Answer 18

Midbrain

Question 19

Where is the Trigeminal, abducent and facial nerve located

Answer 19

Pons

Question 20

Where is the Vestibulochlear nerve located

Answer 20

Pontomedullary Junction

Question 21

Where is the Glossopharyngeal, Vagus, Accessory and Hypoglossal located

Answer 21

Medulla

Question 22

Bilateral III signs

Answer 22

Midbrain

Question 23

III +IV+VI signs

Answer 23

Superior orbital fissure

Question 24

V + VIII signs

Answer 24

cerebellopontine angle

Question 25

How can cranial nerves be damaged

Answer 25

* Within brain- ischaemia, tumour * Crossing the sub-arachnoid space- meningitis * Outside the skull- by base of skull tumours arising in nasopharynx

Question 26

Name some features of Optic Neuritis

Answer 26

* Demyelination within the optic nerve * Monocular visual loss * Pain on eye movement * Reduced visual acuity * Reduced colour vision * Optic disc may be swollen * Often associated with MS

Question 27

Describe Parasympathetic control of the the pupillary response

Answer 27

- constriction of the pupil - loss of parasympathetic input results in a fixed, dilated pupil - e.g. complete third nerve palsy

Question 28

Describe sympathetic pupillary response

Answer 28

- pupillary dilatation | - damage anywhere within the sympathetic pathway can lead to a constricted pupil

Question 29

Name some causes of dilated pupils

Answer 29

* Youth * Dim lighting * Anxiety, excitement * “Mydriatic” eye drops * Amphetamine, cocaine overdose * Third nerve palsy * Brain death

Question 30

Name some causes of small pupils

Answer 30

* Old age * Bright light * “Miotic” eye drops * Opiate overdose * Horner’s Syndrome

Question 31

Name causes of isolated third nerve palsy

Answer 31

o Microvascular- diabetes, hypertension- painless, pupils spared o Compressive- posterior communicating artery aneurysm, raised ICP- painful, pupil affected • Isolated fourth nerve palsy- Trochlear

Question 32

Name causes of isolated sixth nerve palsy

Answer 32

o Idiopathic o Diabetes o Meningitis o Raised ICP

Question 33

Name features and causes of Nystagmus

Answer 33

``` o Congenital o Serious visual impairment o Peripheral vestibular problem o Central vestibular / brainstem disease o Cerebellar disease o Toxins (medication and alcohol) ```

Question 34

Describe Bell's Palsy

Answer 34

``` LMN type Unilateral weakness • Often preceded by pain behind ear • Eye closure affected • Risk of corneal damage • Treated with steroids • Usually good recovery ```

Question 35

Describe Supranuclear lesion

Answer 35

Lesion in the cortex UMN type Forehead unaffected due to bilateral nerve supply to the upper part of the face

Question 36

What is Dysarthria

Answer 36

– disordered articulation, slurring of speech

Question 37

What is Dysphagia

Answer 37

– difficulty swallowing

Question 38

When does Dysarthria and Dysphagia occur together

Answer 38

Bulbar abd pseudobulbar palsy

Question 39

Describe Bulbar palsy

Answer 39

 Bilateral LMN lesion affecting IX-XII

Question 40

Name causes of Bulbar palsy

Answer 40

 MND  Polio  Tumours  Vascular lesions of the medulla and syphilis

Question 41

What are the clinical features of bulbar palsy

Answer 41

```  Wasted, fasciculating tongue  Dysarthria  Dysphonia  Dysphagia  Beware of feeding these patients ```

Question 42

Describe Pseudobulbar palsy

Answer 42

Bilateral UMN lesion | In vascular lesions of both internal capsules

Question 43

Name clinical symptoms of Pseudobulbar palsy

Answer 43

```  Dysarthria  Dysphonia  Dysphagia  Spastic immobile tongue  Brisk jaw jerk  Brisk ag reflex ```