Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NEUROLOGY > Cranial Nerve Problems > Flashcards

Cranial Nerve Problems Flashcards

1
Q

The 4 groups of cranial nerve nuclei?

A

Cortex - 1, 2
Midbrain - 3, 4
Pons - CN 5-8
Medulla (aka bulb) - CN 9-12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

UMN cranial nerve lesions:

This is a lesion of the cortex or corticobulbar tract. What cranial nerves are supplied by the corticobulbar tracts and why?

A

All except 3, 4 and 6.

The corticobulbar tract supplies these cranial nerves on its way to the medulla.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

UMN cranial nerve lesions:

Why do you not get significant deficit?

A

Most CN nuclei are bilateral, though contralateral supply is often stronger.

THE EXCEPTION IS CN 7 - Facial nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

UMN cranial nerve lesions:

Why does a cortical (central) lesion on CN 7 only cause paralysis of half of the face?

A

The muscles responsible for eyelid and forehead movements are innervated by fibres from both sides.

Central facial palsy: unilateral lesion between cortex and brainstem nuclei → muscles of the eyelids and forehead are still supplied by input from the other side → function is preserved

Peripheral facial palsy: unilateral lesion between nuclei and muscles → no input to the ipsilateral eyelid and forehead muscles → paralysis

The lower facial muscles are only innervated by fibers from the contralateral hemisphere (via ipsilateral nuclei and the ipsilateral peripheral nerve) → paralyzed in both central and peripheral facial palsy

https://www.amboss.com/us/knowledge/Facial_nerve_palsy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

LMN cranial nerve lesions:

Where is the lesion found? - 2

What does this lead to? - ipsi/contra

What may cause lesions? - think extrinsic and intrinsic?

A

Lesions of the CN nuclei or nerve fibres

Ipsilateral loss of function

E - compression (tumour, aneurysm, trauma)
I - Ischaemia, inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

LMN cranial nerve lesions:

How would:

  • CN5 - 1
  • CN 8 - 2
  • CN 9, 10 and 12 - What would the palsy be called? 2 signs?
  • CN 10 lesions
  • CN 11 lesions
  • CN 12 lesions
A

Reduced facial sensation

Deaf and dizziness

Bulbar palsy:

  • Dysarthria - difficulty articulating
  • Dysphagia - difficulty swallowing

Uvula deviates to the unaffected side when saying ‘ah’
Impaired gag reflex

Decreased strength in neck and shoulders

The tongue protrudes towards lesion side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Cranial nerve 3, 4 and 6 lesions:

What extraocular muscles do the horizontal movement? - 2

What does the superior rectus do?

What does the inferior rectus do?

A

Lateral and medial rectus muscle

Looks up and out

Looks down and out

https://www.amboss.com/us/knowledge/Eye_and_orbit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Cranial nerve 3, 4 and 6 lesions:

What do the oblique muscle look towards do?

What muscles do they work with to look straight up or down?

What is an important fact to remember about the direction the superior and inferior obliques move the eye in?

A

They both look towards the nose

What looks down

Inferior/superior rectus

IT IS THE OPPOSITE OF WHAT YOU THINK:
Superior oblique = down
Inferior oblique = up

THEREFORE:
Upward gaze = SR + IO
Downward gaze = IR +SO

https://www.amboss.com/us/knowledge/Eye_and_orbit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Cranial nerve 3, 4 and 6 lesions:

What muscles do the above nerves supply?

A

LR6SO4

CN 3 - Oculomotor:

  • Medial rectus
  • Superior rectus
  • Inferior rectus
  • Inferior oblique

CN 4 - Trochlear - Superior oblique

CN 6 - Abducents - Lateral rectus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Cranial nerve 3, 4 and 6 lesions:

What 2 other things does CN 3 - oculomotor - control?

A

Pupil diameter

Levator palpebrae superioris - lifts the eyelid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Cranial nerve 3 lesions - Causes:

Intrinsic cause do to….? - 1

Extrinsic:

  • What aneurysm in the brain may lead to compression? - - How does this present?
  • What sinister thing could the aneurysm lead to?
  • How can raised ICP cause compression of CN3?
  • What 2 things can cause a cavernous sinus lesion?
A

Ischaemia via DM (microvascular)

Posterior communicating artery aneurysm

Headache - a sign of impending rupture

You can get uncal herniation and CN3 passes just medially to the uncus - https://medical-dictionary.thefreedictionary.com/uncal+herniation

Tumour
Aneurysm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Cranial nerve 4 lesions:

Why is this not relevant?

A

Isolated CN4 lesions are very rare!!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Cranial nerve 6 lesions:

What is the main cause?

What degenerative disease can also cause lesions?

A

Raised ICP

MS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Other causes of eye muscle dysfunction:

What NMJ disorder may cause eye muscle dysfunction?

What is ophthalmoplegia and what endocrine condition may cause this?

A

Myasthenia gravis - pupils spared

Paralysis of the muscles within or surrounding the eye

Thyroid disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Presentation of eye problems:

General presentation of eye weakness?

A 
Diplopia 
Impaired movement (paralytic squint) - LOOK UP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Presentation of eye problems:

CN 3 lesion - 3 presentations?

What reflexes are reduced? - 2

What can be used to distinguish between compressive causes (e.g. parasympathetic fibres) and intrinsic causes (e.g. ischaemia)?

A

Down and out - SO (down) and LR (out) still working
Ptosis - weakness of upper eyelids
Dilated pupils - controls muscles of pupils

THE PUPILS

Compressive causes mydriasis (dilation of the pupils)
Intrinsic (e.g. ischaemia) - usually pupil sparing

17
Q

Presentation of eye problems:

What is the likely cause if 2 adjacent nerves are affected?

What is the likely cause if > 2 CNs are affected with nystagmus?

What is the likely cause if > 2 CNs are affected WITHOUT nystagmus?

Why should you just say what you see when describing a lesion instead of saying it is a CN 6 problem for example?

A

Compression

CNS

Myasthenia gravis (You can check for fatigability by getting them to hold eyes in upward gaze)
Myopathy

They may present with an inability to abduct on the left but it does not mean they have a CN 6 problem, it could be an NMJ problem, from the brainstem itself.

18
Q

Cranial nerve 7 problems:

How do they present? - 2

What reflexes are reduced?

A

Weak muscles of facial expression, including the upper half
Reduced taste on the anterior tongue

Reduced corneal and blink reflexes

19
Q

Cranial nerve 7 problems - Causes:

Bells palsy:

  • Onset
  • Treatment
  • Recovery

Intrinsic cause:

  • What infections may cause problems?
  • What inflammatory diseases may cause problems?
A

Acute - hours/days

Prednisolone if in first 72 hrs
Combine with antiviral - acliclovir, valaciclovir

Weeks to months 
----------
VZV - Ramsey-Hunt syndrome
Otitis media 
Lyme disease 
HSV

Sarcoidosis
Guillain Barre
MS

20
Q

Cranial nerve 7 problems - Causes:

Extrinsic:

Trauma is an obvious cause.

  • Where may a tumour be that can compress the nerve?
  • Ear tumour
  • Tumour of CN 8
A

Parotid gland carcinoma

Cholesteatoma

Acoustic neuroma

THIS IS WHY YOU NEED TO DO OTOSCOPY FOR THOSE WITH CN 7 PROBLEMS.

21
Q

Post-heRpatic neuralgia:

It can happen anywhere in the body. What CN can it also affect?

What virus causes this?

How do they describe the pain?

What happens before the pain presents?

What else could occur on the area affected?

A

CN 5 - trigeminal - sensory root affected

Herpes zoster virus - HZV

Burning, aching, debilitating pain

After a shingles infection

Scarring - look up - usually very severe

NEUROLOGY (48 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions