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Flashcards in Cranial Nerve Disorders Deck (29)
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1
Q

What Cranial nerve(s) would be affected by a midbrain lesion?

A

Oculomotor Bilaterally

2
Q

What Cranial nerve(s) would be affected by a lesion in the Sup Orbital fissure? [4]

A

Oculomotor
Trochlear
Abducens
Opthalmic (V1)

3
Q

What Cranial nerve(s) would be affected by a lesion in the Pontomedullary junction? [3]

A

VI
VII
VIII

4
Q

What Cranial nerve(s) would be affected by a lesion at the cerebellopontine angle? [2]

A

Trigeminal & Vestibulocochlear

5
Q

Describe some lesions that could damage a cranial nerve? [3]

A

ISchaemia or tumour within the brain

Meningitis or SAH whilst crossing the subarachnoid space

Skull tumours outside the cranium

6
Q

Name a condition that can cause optic neuritis?

A

MS

7
Q

What are the symptoms of optic neuritis? [4]

A
  • Monocular visual loss
  • Pain on eye movement
  • Reduced visual acuity & Colour vision
  • Papilloedema
8
Q

What could cause a dilated pupil?
Physiological [3]
Pathological [4]

A

Physiological:

  • Youth
  • Dim lighting
  • Anxiety or Excitement

Pathological:

  • Mydriatic eye drops
  • Amphetamines/cocaine
  • third nerve palsy
  • Brain death
9
Q

What could cause a constricted pupil?
Physiological [2]
Pathological [3]

A

Physiological:

  • Old Age
  • Bright Light

Pathological:

  • Miotic Eye Drops
  • Opiates
  • Horners Syndrome (comes with anhydrosis and ptosis)
10
Q

Define Horner’s Syndrome

A

Something cutting off or compressing the sympathetic innervation to the eye and face (unilateral)

Can be intracranial lesions at the point where the sympathetic fibres leave thalamus and enter brainstem or in spinal cord or after they leave the spinal cord (e.g. pancoast tumour)

It causes:

  • Miosis (Constricted pupil)
  • Anhydrosis
  • Ptosis
11
Q

What type of cranial nerve palsies can cause eye movement disorders? [4]

A
  • Isolated nerve palsy to III, IV or VI
  • Any combination of the above
  • Supranuclear gaze palsy
  • Nystagmus (VIII)
12
Q

What is a supranuclear gaze palsy?

A

An inability to look in a particular direction due to impairment in the cerebrum (Above the cranial nerve nuclei)

13
Q

What could cause an Isolated III nerve palsy? [2]

A

Microvascular conditions like diabetes or hypertension could cause a painless, pupil sparing III palsy

Compressive conditions like raised ICP or a Post. Comm. Art. Aneurysm could cause a a painful III palsy with a dilated pupil

14
Q

What could cause an isolated VI nerve Palsy? [4]

A
  • Idiopathic
  • Diabetes
  • Meningitis
  • Raised ICP
15
Q

What are the common causes of pathological nystagmus?

A
  • Congenital (may never notice visual problems)
  • Visual impairment
  • Vestibular problems
  • Brainstem disease (Affecting VIII)
  • Cerebellar Disease
  • Alcohol
  • Toxic Med
16
Q

Name 2 meds that can cause pathological nystagmus?

A
  • Phenytoin
  • Carbamazepine

Both are epileptic medications

17
Q

What causes Trigeminal Neuralgia?

A

A vascular loop compressing the V nerve in the posterior fossa

18
Q

What is trigeminal neuralgia?

A

Paroxysmal attacks of Lancinating pain (Stabbing/piercing) in the face

Brought on my temp changes, wind, touch or chewing

19
Q

Define Bell’s Palsy? [4]

Mx

A

A LMN idiopathic facial nerve palsy:

  • Unilateral facial weakness
  • Often preceded by ear pain
  • Risk of corneal damage form open eye

Mx: steroids

20
Q

Whats different about an UMN and LMN Facial nerve palsy?

A

Facial nerve fibres to lower face (below zygomatic arch) have UMNs from the contralateral cortex
So in an UMN or LMN lesion the lower face is always affected

However the facial nerve fibres to the upper face recieve UMNs from both hemispheres
Meaning if theres an UMN lesion the forehead is spared but a LMN will affect that entire side of the face

21
Q

Examples of UMN vs LMN facial palsies?

A

UMN - Stroke or tumour

LMN - Bells Palsy, Lymes disese or sarcoid

22
Q

What is Vestibular Neuronitis? [3]

Prognosis?

A

Sudden onset VIII palsy causing:

  • Vomiting
  • Disabling Vertigo

They tend to recover fully over a few weeks

23
Q

What are bulbar and pseudobulbar palsy?

A

Palsies afffecting the 9th-12th cranial nerves causing Inability to control movements (such as chewing and speaking)

Due to bilateral lesions of the:
- corticobulbar tracts i.e.
UMNs (Pseudobulbar)
- Motor Cranial Nerves i.e. LMNs (Bulbar)

24
Q

What could cause pseudobulbar palsy? [3]

A

Bilateral UMN lesion

  • Vascular lesions of both internal capsules
  • Motor Neuron Disease
25
Q

Difference between pseudobulbar [3] and bulbar palsy [4] presentations?

A

Bulbar (LMN):

  • wasted, fasciculating tongue
  • dysarthria (slurred Speech)
  • dysphonia (Abnormal sound production)
  • dysphagia

Pseudobulbar (UMN):

  • Hyperreflexia (Gag, Jaw Jerk)
  • Dysarthia, Dysphonia, Dysphagia
  • Spastic Immobile Tongue
26
Q

What should you be careful of in patients with bulbar or pseudobulbar palsies?

A

Feeding them, they will likely choke

27
Q

What could cause Bulbar Palsy? [6]

A

Bilateral LMN lesions affecting IX-XII

  • MND
  • Polio
  • Tumour
  • Vascular lesion of medulla
  • Syphilis
28
Q

Internuclear ophthalmoplegia
Pathophysiology [2]
Causes [2]

A

Ax

  • a cause of horizontal disconjugate eye movement
  • due to a lesion in the medial longitudinal fasciculus, which connects the IIIrd, IVth and VIth cranial nuclei

Causes

  • multiple sclerosis
  • vascular disease
29
Q

Internuclear ophthalmoplegia presentation [2]

A

impaired adduction of the eye on the same side as the lesion

horizontal nystagmus of the abducting eye on the contralateral side