Disorders of Cranial Nerves Flashcards
name the cranial nerves
I - Olfactory VII - Facial II - Optic VIII-Vestibulocochlear III - Oculomotor IX - Glossopharyngeal IV - Trochlear X - Vagus V - Trigeminal XI - Accessory VI - Abducens XII - Hypoglossal
where does the olfactory nerve supply?
nose
where does the optic nerve supply?
eye
where do the oculomotor, trochlear and abducens supply?
eye muscles
where does the trigeminal nerve supply?
sensory to the face, sinuses, teeth etc
ophthalmic, maxilary and mandible
where does the facial nerve supply?
facial muscles of face
where does the vestibulocochlear supply?
ear
where does the glossopharyngeal supply?
sensory- posterior part of tongue, tonsil, pharynx
motor- pharyngeal, musculature
where does the vagus nerve supply?
motor- heart, lungs, bronchi, GI tract
sensory- heart, lungs, bronchi, trachea, larynx, external ear
where does the accessory nerve supply?
sternocleidomastoid, trapezius
where does the hypoglossal nerve supply?
tongue muscle
what are the functions of the cranial nerves?
“Special” senses
“Ordinary” sensation
Control of muscle activity
Autonomic functions
what nerves have “special” senses?
Olfaction (I)
- Vision (II)
- Taste (VII, IX and X)
- Hearing - and balance (VIII)
what nerves have “ordinary” sensation?
Mainly the Vth (trigeminal nerve)
The ear from the VIIth (facial) and IXth (glossopharyneal) nerves
what muscles control the eye muscles?
III (oculomotor), IV (trochlear) and VI (abducence)
what muscles control mastication?
V (trigeminal)
what mucles control facial expression?
VII (facial)
what muscles control larynx and pharynx?
mainly X (vagus)
what is the parasympathetic innervation for pupillary contraction?
III (oculomotor)
what is the parasympathetic innervation for lacrimation?
VII facial
what is the parasympathetic innervation for salivation?
submandibular and sublingual glands – VII (facial)
parotid gland - IX (glossopharyngeal)
what is the parasympathetic innervation for organs in the thorax and abdomen?
vagus X
what do we test in olfactory nerve?
smell – unilateral or bilateral loss
what do we test in optic nerve?
visual acuity visual fields pupillary reactions fundoscopy colour vision
what do we test in oculomotor, trochlear, abducens nerve?
any evidence of ptosis?
pupil of equal size?
pupillary reactions
eye movements – vertical and horizontal
what do we test in trigeminal nerve?
sensation in the ophthalmic, maxillary and mandibular divisions
power in the muscles of mastication
corneal reflex
jaw jerk
what do we test in facial nerve?
Muscles of facial expression
Corneal reflex
Taste
what do we test in vestibulocochlear nerve?
Hearing using Rinne’s and Weber’s tests
Vestibular function using Dix-Hallpike manoevre and Untenberger’s test
balance
what do we test in glossopharyngeal and vagus nerve?
movement of the palate
gag reflex quality of speech quality of cough
what do we test in accesory nerve?
Head turning and shoulder shrugging
what do we test in hypoglossal nerve?
Appearance, movement and power of tongue
what are the afferent and efferent reflexes of pupillary light reaction?
afferent – II ; efferent – III
what are the afferent and efferent reflexes of corneal reflex?
afferent – V ; efferent – VII
what are the afferent and efferent reflexes of jaw jerk
afferent and efferent – V
what are the afferent and efferent reflexes ofgag reflex
afferent – IX ; efferent - X
where does the III and IV (Oculomotor and Trochlear) nuclei lie?
in the MID-BRAIN
where does the V, VI AND VII (Trigeminal, Abducent and Facial) lie ?
in the PONS
where does the VIII (Vestibulocochlear) lie
at the PONTOMEDULLARY junction
where does the IX, X XI and XII (Glossopharyngeal, Vagus, Accessory and Hypoglossal ) lie
in the MEDULLA
what can cause double vision other than cranial nerve lesion?
myasthenia or thyroid eye
disease
what can cause cranial nerve damage within the brain ?
ischaemia, tumour
what causes cranial nerve damage crossing the sub-arachnoid space?
meningitis
what causes cranial nerve damage outside the skull?
base of skull tumours arising in nasopharynx
what happens as a result of optic neuritis?
demyelination within the optic nerve monocular visual loss pain on eye movement reduced visual acuity reduced colour vision optic disc may be swollen often associated with multiple sclerosis
what are the parasympathetic pupillary responses?
constriction of the pupil
what would happen if there was a loss of parasympathetic input to pupillary response?
loss of parasympathetic input results in a fixed, dilated pupil
e.g. complete third nerve palsy
what are the sympathetic pupillary responses?
pupillary dilatation
what would happen if there was loss of sympathetic input to pupillary response?
constricted pupil
what are the causes of dilated pupils?
Youth Dim lighting Anxiety, excitement “Mydriatic” eye drops Amphetamine, cocaine overdose Third nerve palsy Brain death
what are the causes of small pupils?
Old age Bright light “Miotic” eye drops Opiate overdose Horner’s Syndrome
what are eye movement disorders?
Isolated third nerve palsy Isolated fourth nerve palsy Isolated sixth nerve palsy Combination of the above Supranuclear gaze palsy Nystagmus
why would microvascular isolated third nerve palsy happen?
diabetes, hypertension
what is the result of microvascular isolated third nerve palsy?
Painless, pupil spared
why would compressive isolated third nerve palsy happen?
posterior communicating
artery aneurysm, raised ICP
what are the result of a compressive isolated 3rd nerve palsy
painful, pupil affected
what are the causes of isolated sixth nerve palsy?
idiopathic
diabetes
meningitis
raised intracranial pressure
what is Nystagmus
Congenital Serious visual impairment Peripheral vestibular problem Central vestibular / brainstem disease Cerebellar disease Toxins (medication and alcohol)
what is trigeminal neuralgia?
Paroxysmal attacks of lancinating pain
what causes trigeminal neurlgia?
Caused by vascular loop
Compression fifth nerve in the posterior fossa
how is trigeminal neuralgia treated?
with carbamazepine
Surgical options if medication resistant
what is bells palsy?
Idiopathic facial nerve palsy)
Unilateral facial weakness
Lower motor neurone type
Often preceded by pain behind ear
what is affected by bells palsy?
Eye closure affected
Risk of corneal damage
how is bells palsy treated?
steroids
give examples of UMN and LMN facial paralysis
UMN- stroke, tumour
LMN- bells palsy, lyme, saarcoid
forehead involvement is unilateral in LMN
what are the symptoms of vestibular neuritis?
Sudden onset Disabling vertigo Vomiting Gradual recovery Cause uncertain ? viral
what is dysarthria?
disordered articulation, slurring of speech
what is dysphagia?
difficulty swallowing
does dysarthria and dysphagia occur in both bulbar and pseudo bulbar palsy?
yes
which one out of bulbar- and pseudobulbar palsy are UMN
Pseudobulbar palsy – upper motor neurone
Bulbar – lower motor neurone
what is pseudobulbar palsy?
Bilateral UMN lesions e.g. in vascular lesions of both internal capsules, MND
symptoms of pseudonulbar palsy?
dysarthria
- dysphonia
- dysphagia
- spastic, immobile tongue
- brisk jaw jerk
- brisk gag reflex
what is bulbar palsy?
Bilateral LMN lesions affecting IX - XII
eg. MND, polio, tumours, vascular lesions of the medulla and syphilis
symptoms of bulbar palsy?
wasted, fasciculating tongue
- dysarthria
- dysphonia
- dysphagia
