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Flashcards in disorders of cranial nerves Deck (64)
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1
Q

what are some functions of cranial nerves?

A

“special” senses
ordinary sensation
control of muscle activity
autonomic functions

2
Q

what are the “special” senses

A

olfaction (I)
vision (II)
taste (VII IX X)
hearing (VIII)

3
Q

what nerves control “ordinary” sensation?

A

mainly trigeminal

the ear from the facial and glossopharyngeal nerves

4
Q

what nerves control the eye muscles?

A

oculomotor
trochlear (SO)
abducens (LR)

5
Q

what nerve controls the muscles of mastication?

A

trigeminal

6
Q

what nerve controls the muscles of facial expression?

A

facial nerve

7
Q

what nerve controls the muscles of the larynx and pharynx?

A

mainly vagus

8
Q

what nerve controls the SCM and trapezius muscles?

A

accessory

9
Q

what branch of the nervous system does autonomic function fall under (for cranial nerves)

A

parasympathetic

10
Q

what is responsible for pupillary constriction

A

oculumotor nerve

11
Q

what is responsible for lacrimation?

A

facial nerve

12
Q

what is responsible for innervating the submandibular and sublingual glands?

A

facial nerve

13
Q

what is responsible for innervating the parotid gland?

A

glossopharyngeal nerve

14
Q

how do we test the function of the olfactory nerve?

A

smell - unilateral or bilateral loss

15
Q

how do we test thefunction of the optic nerve?

A
visual acuity
visual fields
pupillary reactions
fundoscopy
colour vision
16
Q

how do we test the cranial nerves that innervate the muscles of the eye?

A

any evidence of ptosis
pupil of equal size
pupillary reactions
eye movements - vertical and horizontal

17
Q

how do we test the function of the trigeminal nerve?

A

sensation in the opthalmic, maxillary and mandibular divisions
power in muscles of mastication
corneal reflex
jar jerk

18
Q

how do we test the function of the facial nerve?

A

muscles of facial expression
corneal reflex
taste

19
Q

how do we test the function of the vestibulocochlear nerve?

A

Rinne and Weber’s tests for hearing

vestibular function using dix hallpike maneuver and utenbergers test

20
Q

how do we test the function of the glossopharyngeal and vagus nerves?

A

movement of palate
gag reflex
quality of speech
quality of cough

21
Q

how do we test the function of the accessory nerve?

A

head turning and shoulder shrugging

22
Q

how do we test the function of the hypoglossal nerve?

A

appearance, movement and power of tongue

23
Q

what cranial nerves are involved in the pupillary light reaction?

A

afferent - II

efferent - III

24
Q

what cranial nerves are involved in the corneal reflex?

A

afferent - V

efferent - VII

25
Q

what cranial nerves are involved in the jaw jerk reflex?

A

afferent and efferent - V

26
Q

what cranial nerves are involved in the gag reflex?

A

afferent - IX

efferent - X

27
Q

where are the nuclei of cranial nerves III and IV?

A

midbrain

28
Q

where are the nuclei of cranial nerves V,. VI and VII located?

A

pons

29
Q

what is the nucleus for cranial nerve VIII located?

A

pontomedullary junction

30
Q

where are the nuclei for cranial nerves IX, X, XI and XII located?

A

medulla

31
Q

where would the lesion be if the signs were bilateral and affecting cranial nerve III?

A

midbrain

32
Q

where would the lesion be if the signs were a combination of cranial nerves III, IV and VI?

A

superior orbital fissure

33
Q

where would the lesion be if the signs were a combination of cranial nerves VI and VII?

A

pons

34
Q

where would the lesion be if the signs were a combination of cranial nerves V and VIII?

A

cerebellopontine angle

35
Q

what would an unusual combination of cranial nerve signs possibly suggest?

A

chronic or malignant meningitis

36
Q

what would PURE motor signs relating to cranial nerve possibly suggest?

A

myasthenia gravis

37
Q

where can cranial nerves be damaged?

A

within the brain
crossing the sub arachnoid space
outside of the skull

38
Q

what is the pathology of optic neuritis?

A

demyelination within the optic nerve

39
Q

what are some signs of optic neuritis?

A
monocular visual loss
pain on eye movement
reduced visual acuity
reduced colour vision
optic disc may be swollen
40
Q

what branch of the nervous system controls constriction of the pupil?

A

parasympathetic

41
Q

what does a loss of parasympathetic input to the eye result in?

A

fixed, dilated pupil

42
Q

what are some causes of dilated pupils?

A
dim lighting
youth
anxiety/excitement
mydriatic eye drops
amphetamine or cocaine OD
third nerve palsy
brain death
43
Q

what are some causes of small (constricted pupils)

A
old age
bright light
miotic eye drops
opiate overdose
horners syndrome
44
Q

what are some eye movement disorders related to cranial nerves?

A
isolated third nerve palsy
isolated fourth nerve palsy
isolated sixth nerve palsy
combination of the above
nystagmus
supranuclear gaze palsy
45
Q

what are the 2 different kinds of isolated third nerve palsy?

A

microvascular

compressive

46
Q

what are some causes of microvascular third nerve palsy?

A

diabetes

hypertension

47
Q

what are some characteristics of microvascular third nerve palsy?

A

painless, pupil spared`

48
Q

what are some causes of compressive isolated third nerve palsy?

A

posterior communicating artery aneurysm

raised ICP

49
Q

what are some characteristics of compressive third nerve palsy?

A

painful

pupil affected

50
Q

what are some causes of isolated sixth nerve palsy?

A

idiopathic
diabetes
meningitis
raised ICP

51
Q

what can cause nystagmus?

A

central vestibular/brainstem disease
cerebellar disease
toxins (medication and alcohol)

52
Q

what is trigeminal neuralgia?

A

paroxysmal attacks of lancinating pain

53
Q

what is trigeminal neuralgia caused by?

A

compression of the fifth cranial nerve in the posterior fossa

54
Q

how is trigeminal neuralgia treated medically

A

carbamazepine

55
Q

what are some features of vestibular neuronitis?

A

sudden onset
disabling vertigo
vomiting
gradual recovery

56
Q

what is dysarthria?

A

disordered articulation, slurring of speech

57
Q

what is dysphagia?

A

difficulty swallowing

58
Q

what is the difference between bulbar and pseudobulbar palsy?

A

bulbar palsy is LMN

pseudo is UMN

59
Q

what is the pathology of pseudobulbar palsy?

A

bilateral UMN lesions

60
Q

what are some signs of pseudobulbar palsy?

A
dysarthria
dysphonia
dysphagia
spastic, immobile tongue
brisk jaw jerk
brisk gag reflex
61
Q

what is the pathology of bulbar palsy?

A

bilateral LMN lesions affecting CN IX - XII

62
Q

what can cause bulbar palsy?

A
MND
polio
tumours
vascular lesions of the medulla
syphilis
63
Q

what are some signs of bulbar palsy?

A

wasted, fasciculating tongue
dysarthria
dysphonia
dysphagia

64
Q

what should you beware of doing to bulbar palsy patients?

A

feeding them