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Flashcards in Disorders of Cranial Nerves Deck (35)
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1
Q

Run through the cranial nerves quick to get the ball rolling `

A
1 - Olfactory 
2 - Optic
3 - Occulomotor
4 - Trochlear 
5 - Trigeminal (opthalmic, maxillary, mandibular)
6 - Abducens 
7 - Facial
8 - Vestibulocochlear 
9 - Glossopharyngeal
10 - Vagus 
11 - Accessory 
12 - Hypoglossal
2
Q

Which of the cranial nerves carry special senses? What are their senses?

A
  • 1: olfaction
  • 2: vision
  • 7, 9, 10: Taste (vagus at root of tongue and epiglottis)
  • 8: hearing and balance
3
Q

Which cranial nerves carry ordinary somatosensory fibres?

A
  • Mainly branches of 5

- The ear from: 7 & 9

4
Q

Are the autonomic functions of the cranial nerves sympathetic or parasympathetic

A

Parasympathetic bilo

5
Q

Which cranial nerves control muscle activity? (& the muscles they control)

A
  • 3, 4, & 6: eye muscles (LR6SO4 - rest 3)
  • 5: Muscles of mastication
  • 7: Muscles of facial expression
  • 9: stylopharyngeus & sup. pharyngeal constrictor
  • 10: Muscles of larynx and pharynx
  • 11: SCM and traps
  • 12: tongue
6
Q

Which cranial nerves have autonomic functions? What are these functions?

A
  • 3: Pupillary constriction
  • 7: Lacrimation
  • 7: Salivation (@ submandibular and sublingual)
  • 9: Salivation (@ Parotid)
  • 10: Input to organs in thorax and abdomen
7
Q

What does clinical examination of the first four cranial nerves test?

A
  • CN I: smell (unilateral / bilateral loss)
  • CN II: visual acuity, visual fields, pupillary reactions, fundoscopy, colour vision
  • CN III: ptosis, pupil size, pupillary reactions, eye moevments
  • CN IV: eye movement
8
Q

What does clinical examination of the second four cranial nerves test?

A
  • CN V: sensation of the face, muscles of mastication, jaw jerk, corneal reflex (?)
  • CN VI: eye movement
  • CN VII: facial expression, corneal reflex, taste
  • CN VIII: hearing and balance
9
Q

What does clinical examination of the last four cranial nerves test?

A
  • CN IX & X: palate movement, gag reflex, speech quality, quality of cough
  • CN XI: head turning and shoulder shrugging
  • CN XII: Appearance, movement and power of tongue
10
Q

Which cranial nerves are involved in the pupillary light reaction?

A
  • CN II: afferent

- CN III: efferent

11
Q

Which cranial nerves are involved in the corneal reflex?

A
  • CN V: afferent

- CN VII: efferent

12
Q

Which cranial nerves are involved in the gag reflex?

A
  • CN IX: afferent

- CN X: efferent

13
Q

Where are the cranial nerve nucleii of III & IV located?

A

In the mid brain

14
Q

Where are the cranial nerve nucleii of VI, VII & VIII located?

A

Pontomedullary junction

15
Q

Where is the cranial nerve nuclei of VIII located?

A

Pontomedullary junction

16
Q

Where are the cranial nerve nucleii of IX, X, XI & XII located?

A

In the medulla

17
Q

Where might issues with cranial nerves III, IV & VI indicate there is a problem?

A

Superior orbital fissure

18
Q

What is optic neuritis? Signs?

A
  • Demyelination within the optic nerve
  • Monocular visual loss
  • Pain on eye movement
  • Reduced visual acuity
  • Reduced colour vision

(often associated with MS)

19
Q

What effect does CN III palsy have on pupillary response?

A
  • Responsible for parasympathetic input (constriction), therefore loss of input causes a fixed, dilated pupil
  • A constricted pupil could indicate damage to the sympathetic pathway (not CN’s)
20
Q

Causes of dilated pupils?

A
  • Youth
  • Darkness
  • Anxiety / excitement
  • Mydriatic eye drops
  • Amphetamine / cocaine OD
  • Third nerve palsy
  • Brain death
21
Q

Causes of isolated third nerve palsy? Effect on pupil?

A

Microvascular (ischaemia)

  • Caused by diabetes / hypertension.
  • Painless, pupil not affected

Compressive

  • Caused by PCA aneurysm / raised ICP
  • Painful, pupil affected
22
Q

What are some causes of cranial nerve palsies?

A
  • Idiopathic
  • Raised ICP (tumour / haemorrhage)
  • Compression (aneurysm / tumour)
  • Ischaemia (microvascular blockages)
  • Infections (meningitis etc.)
23
Q

What can cause Nystagmus?

A
  • Congenital (inherited)
  • Inner ear pathology
  • MS
  • Stroke
  • Substance abuse (alcohol / pharmaceuticals)
  • Head trauma
  • Cerebellar disease
24
Q

What is trigeminal neuralgia? What usually causes it?

A
  • Paroxysmal attacks of stabbing pain

- Usually due to compression of trigeminal nerve (vascular abnormalities / tumours / raised ICP)

25
Q

Treatment for trigeminal neuralgia?

A
  • Carbamazepine

- Surgery if medication resistant

26
Q

What is bell’s palsy? Clinical signs?

A
  • Facial nerve palsy
  • Unilateral facial weakness
  • Drooping eyelid / corner of the mouth
  • Drooling
  • Loss of taste / dry mouth
  • Problems with eye closure
27
Q

Treatment for Bell’s Palsy?

A
  • Corticosteroids (reduce inflammation of CN VII)
28
Q

How do you distinguish between LMN facial paralysis and UMN facial paralysis?

A
  • Forehead involvement

In LMN lesion the forehead will be fully involved (wrinkled), in UMN lesion the forehead isn’t involved

Due to facial nerve having two nucleii at brainstem, not fully contralateral inn.

29
Q

What is vestibular neuronitis? Signs?

A
  • Inflammation of CN VIII causing disabling sense of vertigo
  • Vomiting
  • Dizziness
  • Vertigo
  • Blurred vision
30
Q

What is dysarthria? Dysphagia? Dysphonia?

A
  • Dysarthria: disordered articulation, slurring of speech
  • Dysphagia: difficulty swallowing
  • Dysphonia: involuntary spasms in voice box causing voice breaks and irregularities in voice sound
31
Q

Is pseudobulbar palsy due to UMN lesion or LMN lesion? What about Bulbar palsy?

A
  • Pseudobulbar palsy: UMN lesion

- Bulbar palsy: LMN lesion

32
Q

What is pseudobulbar palsy? Signs?

A
  • Bilateral damage to corticobulbar pathways (UMN)
  • Dysarthria / dysphonia / dysphagia
  • Spastic / stiff tongue
  • brisk jaw jerk
  • Brisk gag reflex
33
Q

What is Bulbar palsy? Signs?

A
  • Bilateral LMN lesions in the medulla or cranial nerves of CN IX, X, XI & XII
  • Wasted, fasciculating tongue
  • Dysarthria / dysphonia / dysphagia
  • Normal or absent jaw jerk
  • Absent gag reflex
34
Q

Causes of bulbar palsy?

A

Bilateral LMN lesions in the medulla or cranial nerves of CN IX, X, XI & XII

  • Motor neurone disease
  • Polio
  • Tumours
  • Vascular lesions of medulla
  • Syphilis
35
Q

Causes of pseudobulbar palsy?

A

Bilateral damage to corticobulbar pathways (UMN)

  • Motor neurone disease
  • Vascular lesions of both internal capsules
  • …?

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