Disorders of Cranial Nerves Flashcards
Which cranial nerves are special sensory?
I - olfaction
II - vision
VII, IX, and X - taste
VIII - hearing
Which cranial nerves are ordinary sensory?
CN V
CN VII
CN IX
Which CN control eye muscles?
III
IV - SO
VI - LR
Which CN controls muscles of mastication?
CN V3
Which CN controls muscles of facial expression?
CN VII (facial)
Which CN controls muscles of the larynx and pharynx?
Mainly CNX (vagus)
Which CN controls the sternocleidomastoid and trapezius muscles/
CN XI (accessory)
Which CN controls lacrimation?
CN VII
Which CN controls salvation from submandibular and sublingual glands?
CN VII
Which CN controls salivation from parotid glands?
CN IX
Which CN controls pupillary constriction?
CN III
How do we test CN I?
Change in smell
Uni or bi lateral
How do we test CN II?
Visual fields Visual acuity Pupillary response Colour vision Fundoscopy
How do we test CN III, IV and VI?
Eye movements
Horizontal and vertical H shape
Equal size pupils
What tests are carried out for CN V function?
Sensation in V1,2,and 3 area Neurotip and cotton wool Corneal reflex (sensory part) Power of muscles of mastication Jaw jerk reflex
How do we test CN VII?
Make facial expressions
Corneal reflex (motor control)
Taste (sometimes)
HOw do we test CN VIII?
Hearing
Rinne’s and Weber;s
What tuning fork is used in hearing tests?
512 Hz
How is CN IX and CN X tested?
Movement of the palate (symmetrical)
Gag reflex
Quality of speech
Quality of cough
How is CN XI tested?
Move shoulders up and down to test the trapzius muscle
Head turning to test the sternocleidomastoid
How is CN XII tested?
Movement of tongue
Test speech
Which is the afferent CN of pupillary reflex?
CN II
What is the efferent CN of pupillary reflex?
CN III
What is the afferent CN of corneal reflex?
CN V
What is the efferent CN of corneal reflex?
CN VII
What is the afferent and efferent CN of jaw reflex?
CN V for both
What is the afferent CN for gag reflex?
CN IX
What is the efferent CN for gag reflex?
CN X
Where are CN III and IV nuclei located in the brain?
Mid brain
Where are CN V, VI and VII nuclei located?
In the pons
Where is CN VIII nuclei located?
In the pontomedullary junction
Where is CN IX, X, XI and XII nuclei located?
In the medulla
What is the differential diagnosis for loss of eye movements, facial weakness and difficulty swallowing?
Stroke
Cranial nerve disorders
What causes optic neuritis?
Demyelination within the optic nerve
What is optic neuritis often associated with?
MS
What are the symptoms of optic neuritis?
Monocular visual loss Pain on eye movement Reduced visual acuity Reduced colour vision Optic disc may be swollen
Palsy of which CN would result in a fixed dilated pupil?
CN III
What can lead to a constricted pupil?
Damage anywhere within the sympathetic pathway
What are causes of dilated pupils?
Youth Dim lighting Anxiety, excitement Drugs 3rd nerve palsy Brain death
What are causes of constricted pupils?
Odl age Bright light Miotic eye drops Opiate overdose Horners syndrome Damage to the sympathetic chain
What can cause eye movement disorders?
Isolated CN III, IV or VI palsy
Combination of the above
Supranucleur gaze palsy
Nystagmus
What are causes of isolated CN III palsy?
Microvascular (diabetes, hypertension)
Compressive ( due to artery aneurysm, raised ICP)
What are causes of isolated CN VI palsy?
Idiopathic
Diabetes
Meningitis
Raised ICP
What are some causes of nystagmus?
Congenital Serious visual impairment Vestibular problems Brainstem disease Cerebellar disease Toxins
What is trigeminal neuralgia?
Paroxysmal attacks of lacinating pain
What causes trigeminal neuralgia?
Compression of 5th nerve root in posterior fossa (caused by vascular loops)
What is the first line treatment for CN V neuralgia?
Carbamazepine
What is the treatment for CN V if medication is resistant?
Surgery
What are the signs of bells palsy?
Unilateral facial weakness
Is bells palsy UMN of LMN lesion?
LMN
What type of pain often precedes bells palsy?
Pain behind the ear
Why is there a risk of corneal damage in bells palsy?
Due to failure to close the eyelid
How is bells palsy treated?
Usually with steroids
What is dysarthria?
Disordered articulation
Slurring of speech
What is dysphagia?
Difficulty swallowing
Is bulbar palsy UMN or LMN?
LMN
Is pseudobulbar palsy UMN or LMN?
UMN
What are the signs of bulbar palsy?
Wasted, fasiculating tongue Dysarthria Dysphonia Dysphagia Norma gag reflex Nasal speech
Which CN is affected in bulbar palsy/
CN IX - CN XII