Disorders of Cranial Nerves Flashcards
what are common combinations of cranial nerve signs?
Bilateral III - midbrain III +IV+VI - superior orbital fissure VI +VII -pons V + VIII - cerebellopontine angle Unusual combinations - ?chronic or malignant meningitis Pure motor signs - ?myasthenia gravis
what is optic neuritis?
demyelination within the optic nerve
often associated with multiple sclerosis
what are symptoms of optic neuritis?
monocular visual loss pain on eye movement reduced visual acuity reduced colour vision optic disc may be swollen
what are causes of dilated pupils?
Youth Dim lighting Anxiety, excitement “Mydriatic” eye drops Amphetamine, cocaine overdose Third nerve palsy Brain death
what are causes of small pupils?
Old age Bright light “Miotic” eye drops Opiate overdose Horner’s Syndrome
what are some eye movement disorders?
Isolated third nerve palsy Isolated fourth nerve palsy Isolated sixth nerve palsy Combination of the above Supranuclear gaze palsy Nystagmus
describe microvascular third nerve palsy
diabetes, hypertension
Painless, pupil spared
describe compressive third nerve palsy
posterior communicating artery aneurysm, raised ICP
Painful, pupil affected
what are causes of isolated sixth nerve palsy?
idiopathic
diabetes
meningitis
raised intracranial pressure
what is Nystagmus?
uncontrolled movement of the eyes
what are causes of 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 facial pain
Middle age and older
Caused by vascular loop
Compression fifth nerve in the posterior fossa
how is Trigeminal Neuralgia treated?
Treated medically with carbamazepine
Surgical options if medication resistant
what is Bell’s Palsy (Idiopathic facial nerve palsy)?
Unilateral facial weakness Lower motor neurone type Often preceded by pain behind ear Eye closure affected Risk of corneal damage Treated with steroids Usually good recovery
what is Vestibular Neuronitis?
infection of the vestibular nerve in the inner ear Disabling vertigo Sudden onset Vomiting Gradual recovery Cause uncertain ? viral
