Cranial nerve findings/questions Flashcards
Causes nystagmus
HORIZONTAL
- Vestibular lesion. Fast phase away from the side of the lesion
- Cerebellar lesion- unilateral Dx= fast phase to lesion. Drift to midline with fast phase in direction of gaze= Gaze evoked. A/W Dysarthria, limb ataxia, hyper/hypometric saccades
- INO- nystagmus in abducting eye, with failure of adduction on affected side. If young- MS, if older- brain stem infarct
VERTICAL Brain Stem Lesion Toxic
Causes pupillary constriction
Horner’s syndrome,
Argyll Robertson pupil,
Pontine lesion (often bilateral and reactive to light),
narcosis, pilocarpine drops, old age
AR pupil- no react to light, react to accomodation. cause= syphilis, diabetes, alcohol
Causes pupillary dilatation
third nerve lesion, Adies pupil, Iridectomy/lens impant/iritis, post trauma, deep coma, cerebral death, congenital, mydriatics
Visual field defect location
Central scotoma= retina optic nerve= monocular vision Bitemporal hemianopia= optic chiasm homonymous hemianopia (away from lesion)= optic tract/radiations
Causes papilloedema
- Space occupying lesion or retro bulbar mass - Hydrocephalus (Associated with large ventricles) – obstructive (tumour), or communicating (tumour, papilloma, meningitis - Idiopathic intracranial hypertension- idiopathy, OCP, addisons, drugs, lateral sinus thrombus, head trauma - Hypertension - Central retinal vein thrombosis - Cerebral venous sinus thrombosis - High cerebrospinal fluid protein level (GBS)
Causes optic atrophy
- Chronic papilloedema or optic neuritis - Optic nerve pressure or division - Glaucoma - Ischaemia - Familial- retinitis pigmentosa, lebers disease, freidreichs ataxia
Causes optic neuropathy
- MS - Toxic- ethambutol, chloroquine, nicotine, alcohol - Metabolic- B12 deficiency - Ischaemia- DM, temporal arteritis, atheroma - Familial- lebers disease - Infective- infectious mononucleosis
Causes ptosis with normal pupils
Senile, Myotonic dystrophy Fascioscapulohumeral dystrophy Ocular myopathy- e.g. mitochondrial myopathy Thyrotoxic myopathy Myasethnia gravus Botulism, snake bite Congenital Fatigue
Causes ptosis with contrsicted pupil
Horners syndrome Tabes dorsalis
Causes ptosis with dilated pupil
third nerve lesion
Features third nerve palsy
Ptosis Divergent strabismus (eye ‘down and out’)- limited adduction and elevation Dilated pupil (unreactive)
Causes third nerve palsy
Central -Vascular (e..g brain stem infarct) -Tumour -Demyelination (rare) -Trauma -Idiopathic Peripheral -Compressive lesions- aneurysm, tumour - Infarction- diabetes mellitus, arteritis (pupil usually spared - Trauma -Cavernous sinus lesions
Features sixth nerve palsy
Failure of lateral movement. +/- convergent strabismus (in) Diplopia- worst by looking to affected side
Causes sixth nerve palsy
Bilateral- head trauma, wernickes encephalopathy, raised ICP, mononeuritis multiplex Unilateral -Central- vascular, tumour, wernicke’s encephalopathy, MS (rare) -Peripheral- diabetes, other vascular lesions, trauma, idiopathic, raised ICP
Causes fifth (trigeminal) nerve palsy
-central (pons, medulla, upper cervical cord)- vascular, tumour, syringobulbia, multiple sclerosis -posterior fossa- aneurysm, tumour (acoustic neuroma), chronic meningitis -Trigeminal ganglion (petrous temporal bone)- meningioma, # -Cavernous sinus (a/w 3rd, 4th and 6th nerve palsies)- aneurysm, thrombosis, tumour -Other- sjogrens syndrome, SLE, toxins, idiopathic Hints -all 3 divisions- ganglion or sensory root. -one division postganglionic lesion -loss pain preserved soft touch-brain stem or upper cervical cord lesion -soft touch lost, pain preserved- pontine nucleus lesion
Causes seventh (facial nerve) palsy
Upper motor neurone lesion (supranuclear)- vascular, tumour FOREHEAD SPARED Lower motor neurone lesion- FOREHEAD INVOLVED - Pontine- often a/w 5th and 6th nerve palsy= Vascular, tumour, syringobulbia, multiple sclerosis -Posterior fossa- Acoustic neuroma, meningioma - Petrous temporal bone- Bells palsy, ramsay hunt syndrome, otitis media, fracture - Parotid- Tumour, sarcoid Bilateral Guillain Barre syndrome Bilateral parotid disease (e.g. sarcoidosis) Mononeuritis multiplex (rare) (myopathy and NMJ defects can cause bilateral facial weakness)
Causes sensorineural hearing loss
Degeneration (presbycusis), Trauma (high noise exposure, fracture of petrous temporal bone etc) Toxic (aspirin, EOTH, streptomycin) Infection- congenital rubella syndrome, congenital syphilis Tumour (acoustic neuroma) Brain stem lesions Vascular disease of the internal auditory artery
Causes 9th (glossopharyngeal) and 10th (vagus) nerve pasly
Central -Vascular (E.g. lateral medullary infarction due to vertebral or posterior inferior cerebellar artery disease), tumour, syringobulbia, motor neurone disease (vagus only) Peripheral- posterior fossa -Aneurysm, tumour, chronic meningitis, Guillain Barre syndrome (vagus only)
Causes 12th (hypoglossal) nerve palsy
Upper motor neurone lesion- vascular, motor neurone disease, tumour, multiple sclerosis NOTE: bilateral UMN lesion of 9th, 10th, 12th nerves= pseudobulbar palsy Lower motor neurone lesion- unilateral -Central- vascular (thrombosis of vertebral artery), motor neurone disease, syringobulbia -Peripheral (posterior fossa)- aneurysm, tumour, chronic meningitis, trauma, Arnold-chiari malformation, fracture/tumour of base of skull Lower motor neurone lesion- bilateral -Motor neurone disease, Arnold chiari malformation, Guillain barre syndrome, polio
Causes multiple cranial nerve palsies
Think cancer first Nasopharyngeal carcinoma Chronic meningitis (e.g. carcinoma, tuberculosis, sarcoidosis) Guillain Barre syndrome (spares CN 1, 2, 8) including miller fischer variant (ataxia, areflexia, and ophthalmoplegia) Brain stem lesions- usually vascular disease causing crossed sensory or motor paralysis (e.g. CN signs on one side, contralateral long tract signs). Gliomas in brain stem can cause similar signs Arnold chiari malformation Trauma Lesion of base of skull (e.g. pagets disease, large meningioma, metastasis) Rarely mononeuritis multiplex (e.g. DM)
Causes horners (ptosis, miosis, anhidrosis)
- Carcinoma of ling apex- likely squamous cell - Neck- thyroid malignancy, trauma - Carotid arterial lesion (carotid aneurysm or dissection, pericarotid tumour, cluster headache - Brain stem lesions- vascular disease (especially lateral medullary syndrome), syringobulbia, tumour - Retro-orbital lesions - Syringomyelia
5 broad causes dysarthria
- Upper motor neurone (pseudobulbar) - Lower motor neurone (bulbar) - Cerebellar - Movement- PD, HD - Muscle Cerebellar- slurred/scanning (irregular, staccato) Pseudobulbar palsy- slow, hesitant, hollow sounding w harsh, strained voice Bulbar- nasal speech with imprecise articulation Motor neurone can be mixed
Expressive aphasia- description, location
- Slow and non fluent - Broca’s- frontal gyrus
Receptive aphasia- - description, location
- Fluent but content poor - Wernicke’s- temporal gyrus
