Disorders of cranial nerves Flashcards
What cranial nerves are responsible for taste?
7,9,10
What cranial nerves allow general sensation in the ear?
7 and 9
Afferent and efferent cranial nerves of pupillary light reflex
afferent = 2 efferent = 3
Afferent and efferent cranial nerves for corneal reflexes
afferent = 5 efferent = 7
Afferent and efferent cranial nerves for jaw jerk reflex
both 5
Afferent and efferent cranial nerves for gag reflex
afferent = 9 efferent = 10
Briefly state the location of the origin of the cranial nerves
3,4 - midbrain
5,6,7 - pons
8 - pontomedullary junction
9-12 - medulla
Causes of unusual cranial nerve signs?
chronic or malignant meningitis
Causes of pure motor cranial nerve signs?
myasthenia gravis
Give 2 examples of cranial nerve signs with no cranial nerve lesion
after stroke
myasthenia gravis, thyroid eye disease - double vision
Causes of cranial nerve damage in the brain
tumour, ischaemia
Causes of cranial nerve damage crossing subarachnoid space
meningitis
Causes of cranial nerve damage outside skull
base of skull tumours arising from nasopharynx
Symptoms of optic neuritis
pain on eye movement
reduced visual acuity and colour vision
What is optic neuritis?
demyelination within the optic nerve
What is the sign of optic neuritis and what is it associated with?
swollen optic disc
MS
Loss of parasympathetic innervation leads to what appearance of the pupil?
fixed, dilated
Loss of sympathetic innervation leads to what appearance of the pupil?
constricted
List some causes of dilated pupils
youth, anxiety, cocaine, brain death, mydriatic eye drops, dim lighting
List some causes of small pupils
bright light, middle age, miotic eye drops, opiate overdose, horners syndrome
Difference between microvascular and compressive 3rd nerve palsy
microvascular is painless and pupil is spared
Causes of microvascular and compressive 3rd nerve palsy
diabetes, hypertension
posterior communicating aneurysm, raised ICP
Causes of isolated 6th nerve palsy
idiopathic, diabetes, meningitis, raised ICP
Causes of nystagmus
congenital, toxins, serious visual impairment, cerebellar disease, peripheral vestibular problem, central vestibular/brainstem disease
What Is trigeminal neuralgia?
paroxysmal attacks of lacinating pain usually in middle age and older
Cause of trigeminal neuralgia?
vascular loop - compression 5th cranial nerve in posterior fossa
How is trigeminal neuralgia treated?
carbamazepine or surgery
What usually precedes bells palsy?
pain behind ear
bells palsy symptoms and signs
unilateral facial weakness
eye closure affected
risk of corneal damage
Is bells palsy LMN or UMN?
LMN
How is bells palsy treated?
steroids
Give an example of UMN and LMN facial nerve palsy
UMN eg stroke, tumour
LMN eg bells palsy
Describe vestibular neuronitis
sudden onset disabling vertigo and vomiting
thought to be viral cause, gradual recovery
dysarthria
disordered articulation and slurring of speech
What is bulbar and pseudobulbar palsy?
bulbar = LMN pseudobulbar = UMN
Causes of pseudobulbar palsy
MND, vascular lesions of both internal capsules
Symptoms of pseudobulbar palsy
dysarthria dysphonia dysphagia spastic, immobile tongue brisk gag and jaw jerk reflex
What cranial nerves does bulbar palsy encompass?
9-12
Causes of bulbar palsy
MND, polio, tumour
Symptoms of bulbar palsy
wasted, fasciculating tongue
dysarthria
dysphonia
dysphagia
What do you need to beware of with bulbar palsy patients?
feeding
