Cranial Nerve Palsies Flashcards
What can cause a cranial nerve palsy?
Tumours
Trauma
Ischaemia
Infections
Clinical features of olfactory nerve palsy
Ansomia
Test for olfactory nerve palsy
Identification of certain smells e.g. peppermint, coffee
Aetiology of olfactory nerve palsy
Trauma to lateral and occipital regions
SOLs
Aetiology of optic nerve palsy
Ischaemic optic neuropathy
Inflammation: MS, sarcoidosis, viral infections
Trauma
Tumours (e.g. optic nerve glioma, pituitary adenoma)
Raised ICP (e.g. hydrocephalus)
B12 deficiency
Drugs: sildenafil, amiodarone, ethambutol
Clinical features of optic nerve palsy
Impaired vision
Complete transection → ipsilateral blindness and loss of direct pupillary reflex
Papilloedema (raised ICP)
Compression (e.g. tumour) → optic atrophy
Pituitary oedema → compression of optic chiasm → bitemporal hemianopia
Test for optic nerve palsy
Visual field test
Visual acuity test
Fundoscopy (e.g. papillitis)
Aetiology of oculomotor nerve palsy
Ischaemic stroke
MS
Aneurysm of posterior communicating
Transtentorial herniation
Cavernous sinus thrombosis
Diabetic cranial mononeuropathy
Clinical features of oculomotor nerve palsy
motor portion
Paralytic squint
Adduction weakness
Down-and-out gaze (exotropia + hypotropia)
Ptosis
Horizontal diplopia (worsens when head turned away from side of the lesion)
Clinical features of oculomotor nerve palsy
sensory portion
Absence of pupillary reaction
Prominent motor dysfunction and sparing of pupil in ischaemic lesions due to vascular disease
Severely impaired pupillary reaction with relatively spared motor function in compression lesions
Aetiology of trochlear nerve palsy
Microvascular damage (diabetes, hypertension, arteriosclerosis)
Cavernous sinus thrombosis
Trauma
Congenital fourth nerve palsy
Clinical features of trochlear nerve palsy
Extorsion of the eye (inability to depress and abduct the eyeball simultaneously)
Diplopia
Mild hypertropia and excyclotorsion
Aetiology of trigeminal nerve palsy
Tumour
Vascular compression
Oral surgery
Inflammation of the nerve
Cavernous sinus thrombosis
Clinical features of trigeminal nerve palsy
Ophthalmic nerve (CNV1): absent corneal reflex, loss of sensation in ipsilateral forehead
Maxillary nerve (CNV2): loss of sensation in ipsilateral midface
Mandibular nerve (CNV3): anaesthesia of ipsilateral lower third of face and anterior 2/3s of tongue, paresis of muscles of mastication
Tenso tympani branch: hearing impairment
Trigeminal nerve nuclei: ipsilateral weakness of muscles of mastication and/or ipsilateral loss of sensation
Aetiology of abducens nerve palsy
Trauma
Pseudomotor cerebri
Cavernous sinus thrombosis
Space-occupying lesion causing downward pressure (e.g. tumour)
Diabetic neuropathy
Congenital: Duane syndrome
Clinical features of abducens nerve palsy
Horizontal diplopia worsens when looking at distant objects
Esotropia: medial deviation of affected eye at primary gaze
Inability to abduct eye (will rotate head to look at the side)
What is the most common ocular cranial nerve palsy?
Vestibulocochlear nerve palsy
Aetiology of vestibulocochlear nerve palsy
Bacterial meningitis (most common cranial nerve palsy)
Lyme disease
Tumour (e.g. acoustic neuroma, neurofibromatosis type 2)
Basilar skull fracture
Clinical features of vestibulocochlear nerve palsy
Sensorineural hearing loss
Vertigo
Horizontal nystgamus
Motion sickness
Tests for vestibulocochlear nerve palsy
Audiometry
Vestibular function - electronystagmography, rotation test
CT/MRI
Aetiology of glossopharyngeal nerve palsy
Idiopathic
Compression of nerve by a blood vessel
Clinical features of glossopharyngeal nerve palsy
Loss of gag reflex (afferent limb)
Loss of carotid sinus reflex
Sensory loss over soft palate, upper pharynx, and posterior third of tongue (inc. loss of taste)
Mild dysphagia
Glossopharyngeal neuralgia (throat and ear pain)
Test for glossopharyngeal nerve palsy
Diminished or absent gag response
Loss of taste in posterior third of the tongue
Aetiology of vagus nerve palsy
Trauma
Diabetes
Inflammation
Aortic aneurysms
Tumours
Surgery (e.g. recurrent nerve injury during thyroidectomy)
Clinical features of vagus nerve palsy
Flaccid paralysis and ipsilateral lowering of soft palate → nasal speech & deviation of uvula away from lesion
Dysfunction of pharyngeal muscles → dysphagia, aspiration
Loss of gag reflex (efferent limb) and/or cough reflex (afferent limb)
Recurrent laryngeal nerve injury:
Lesion of one nerve: unilateral vocal cord paralysis → dysphonia (hoarseness)
Lesion to both nerves: bilateral vocal cord paralysis → aphonia and inspiratory stridor
Gastroparesis
Cardiovascular dysfunction e.g. tachycardia
Test for vagus nerve palsy
Diminished/absent gag and/or cough reflex
Saying “ahhh” will cause uvula to deviate away from affected side
Indirect laryngoscopy - vocal cord possibly in paramedian or intermediate position
Water swallow tests - coughing, choking or dysphonia
Increased resting heart rate
Gastroparesis on endoscopy
Aetiology of accessory nerve palsy
Iatrogenic
Most commonly from surgical resection of cervical lymph nodes
Clinical features of accessory nerve palsy
Paresis, atrophy and/or asymmetry of SCM
Paresis, atrophy and/or asymmetry of the trapezius muscle → ipsilateral shoulder drooping and lateral winging scapula
Test for accessory nerve palsy
Possibly asymmetrical neckline
Shrug shoulders → weakness during elevation of ipsilateral shoulder
Turn head from side to side → weakness turning head towards contralateral side
Aetiology of hypoglossal nerve palsy
Tumours
Trauma
Dissection of internal carotid artery
Clinical features of hypoglossal nerve palsy
Atrophy
Fasciculation of the tongue on the side of the lesion
Test for hypoglossal nerve palsy
Signs of unilateral lower motor neurone damage: tongue atrophy, fasciculations, asymmetry
Tongue deviates to side of lesion due to weakness of ipsilateral muscles
What is Bell’s palsy?
An acute, unilateral, idiopathic, facial nerve paralysis
Clinical features of Bell’s palsy
LMN facial nerve palsy - forehead affected
UMNL “spares” the upper face
Post-auricular pain
Altered taste
Dry eyes
Hyperacusis
Management of Bell’s palsy
Oral prednisolone within 72hrs onset
Eye care - artificial tears/lubricants
What is Horner’s syndrome?
Ptosis and meiosis with or without anhydrosis
Aetiology of Horner’s syndrome
Pancoast tumour (affecting sympathetic nerve supply)
Stroke
Carotid artery dissection
