Disorders of Cranial Nerves Flashcards
what are the four special senses?
smell
vision
taste
hearing/balance
what nerve is responsible for smelling?
olfaction
what nerve is responsible for smelling?
optic
what nerves is responsible for taste?
facial
vagus
glossopharyngeal
what nerve is responsible for hearing ?
vestibulocochlear
what nerve supplies sensation to the face?
trigeminal
what nerve supplies the lateral rectus ?
abducens
what nerve supplies the superior oblique ?
trochlear
what nerves supply the muscles of mastication ?
mandibular branch of trigeminal
what nerves supply the muscles of mastication ?
the facial nerve
what nerve supplies taste to the anterior part of the tongue ?
chorda tympani of the facial nerve
what nerve supplies the trapezius and SCM?
accessory nerve
what nerve supplies the muscles of the pharynx and larynx ?
vagus
what nerves contain parasympathetic fibres ?
3 - oculomotor
7 - facial
9 - glossopharyngeal
10 - vagus
what nerve causes pupillary constriction ?
oculomotor
what nerve causes tearing of the eye from the lacrimal gland ?
facial
what nerve causes salvation from the parotid gland ?
glossopharyngeal
what nerve causes salvation from the submandibular and sublingual gland ?
facial
what tests can be dine to test the optic nerve ?
visual acuity visual fields pupillary reactions fundoscopy colour vision
what four tests can be done to test the trigeminal nerve ?
sensation - light touch and neurotip power of muscles of mastication corneal reflex jaw jerk
what three tests can be done to test the facial nerve ?
muscles of facial expression
corneal reflex
taste
what facial movements should be done to test the facial nerve ?
- raise eyebrows
- clench teeth
- bloat out cheeks
- clench eyes together
what is the rinnes test ?
hearing test testing the vestibulocochlear nerve
- by placing a 512Hz tuning fork on the persons forehead and asking if they can hear the vibrations in both ears
what is webers test?
hearing test testing the vestibulocochlear nerve
- by placing the 512Hz tuning fork in front of the external ear canal and then placing it on the mastoid process on the temporal bone and asking if the person can hear both and which one is louder.
- the one in front of the ear should be louder
what is Dix-Hallpike manoeuvre used for ?
for vertigo and dizziness
what does the Untenbergers test involve ?
standing patient closing their eyes and checking if they fall over or not
what tests can be done to test the glossopharyngeal and vagus nerve ?
movement of palate
gag reflex
quality of speech
quality of cough
what can be done to check the function of the hypoglossal nerve ?
appearance, movement and power of the tongue
how is the power of the tongue tested?
asking the person to push their tongue into the side of their cheek and feel how strong it is
what nerves nuclei lie in the mid brain ?
3rd and 4th
oculomotor and trochlear
what nerves nuclei lie in the pons ?
5th, 6th, 7th and 8th
which nerve nuclei lies in the pontomedullary junction ?
8th
- vestibulocochlear
what nerves nuclei lie in the medulla ?
9th, 10th, 11th and 12th
what condition results in loss of pure motor signs?
myasthenia gravis
give 3 examples of conditions which can damaged cranial nerves within the brain ?
- ischaemia
- tumour
- increased ICP
give an example of conditions which can damaged cranial nerves crossing the subarachnoid space ?
meningitis
give an example of conditions which can damaged cranial nerves outside the skull?
base of the skull tumours
what does optic neuritis result in, in relation to the optic nerve ?
demyelination within the optic nerve
what causes demyelination in the optic nerve during optic neuritis ?
inflammation
the symptoms does someone with optic neuritis experience ?
monocular visual loss
pain on eye movement
reduced visual acuity and colour vision
what condition is optic neuritis associated with ?
multiple sclerosis
what would be seen on fundoscopy fora patient with optic neuritis ?
optic disc may be swollen
what test can be done to test the conduction of the optic nerve ?
visual evoked response
- delayed response would suggest demyelination
what autonomic response causes pupil dilation ?
sympathetic
what autonomic response causes pupil constriction ?
parasympathetic
what would the pupil look like if the sympathetic fibres were damaged ?
fixed constricted
what would the pupil look like if the 3rd cranial nerve fibres were damaged ?
fixed dilated pupil
state some causes of dilated pupils?
- youth
- dim lighting
- anxiety, excitement
- “mydriatric” eye drops
- cocaine, amphetmine
- third nerve palsy
- brain death
state some causes of small pupils?
- old age
- bright lights
- “miotic” eye drops
- opiates overdose
- Horners syndrome
what are the two categories of causes of third nerve palsy ?
microvascular
compressive
state some microvascular causes of 3rd nerve palsy?
HT
Diabetes
state some compressive causes of 3rd nerve palsy?
SAH
Raised ICP
Aneurysm
state the two clinical signs of microvascular 3rd nerve palsy
painless
pupil is spared
state the two clinical signs of compressive 3rd nerve palsy
painful
pupil is affected
state four causes of 6th nerve palsy ?
idiopathetic
diabetes
meningitis
raised ICP
state some causes of nystagmus
congenital serious visual impairment peripheral vestibular problem central vestibular disease cerebellar disease toxins
what two toxins can cause nystagmus ?
alcohol
anti epileptics
what symptom is experienced with trigeminal neuralgia ?
paroxysmal (short frequent) attacks of laminating (piercing stabbing) pain
what age range is most effected by trigeminal neuralgia ?
middle aged and older people
what causes trigeminal neuralgia ?
compression of 5th nerve
what medication is used to treat trigeminal neuralgia ?
carbamazepine
as well as medication what other options are available for trigeminal neuralgia ?
surgical options when medication is resistant
what is the cause of idiopathic facial nerve palsy (bells palsy)?
unknown cause
what is the symptom of bells palsy ?
unilateral facial weakness
what can a complication be of a bells palsy patient when they can’t come their eye properly ?
their eye can dye out and they can lose their vision
- risk of corneal damage
what is bells palsy treated with ?
steroids
how are UMN and LMN disorders involving paralysis of the face differ?
- UMN
UMN disorders (stroke)
- for example if the lesion was in the internal capsule on one side
- then some fibres from the contralateral side of the lesion will ipsilaterally to the forehead
- so patients with UMN will not have complete unilateral paralysis as the forehead may still be able to move
how are UMN and LMN disorders involving paralysis of the face differ?
- LMN
LMN disorders (Bells palsy)
- the lesion is lower down as the nerve has already left the brain stem
- all fibres travelling to the contralateral side of the lesion will be affected so the forehead will not be able to move
- therefore the patient will have complete unilateral paralysis
what is dysarthria ?
slurring of speech
what is dysphagia?
difficulty swallowing
what is dysphasia ?
difficulty to generate speech
is pseudo bulbar palsy an UMN or LMN disease?
UMN
is bulbar palsy an UMN or LMN disease?
LMN
are bulbar and pseudo bulbar palsy caused by unilateral or bilateral lesions ?
bilateral
what are two causes of pseudo bulbar palsy ?
vascular lesions in both internal capsules
motor neurone disease
what are some causes of bulbar palsy ?
motor neurone disease polio syphilis tumours lesions in the medulla
what cranial nerves are affected during bulbar palsy ?
9-12 nerves
- nerves passing out go the medulla
state some symptoms/clincal signs of pseudo bulbar palsy ?
dysarthria dysphonia dysphagia immobile tongue brisk jaw and gag reflex
what is dysphonia ?
loss in volume
what is dysarthria ?
difficulty to articulate speech as muscles don’t work properly
state some symptoms and clinical signs for bulbar palsy ?
wasted, fasciculating tongue
dysarthria
dysphonia
dysphagia
