Cranial nerves again Flashcards
What happens if you have a CNII lesion?
marcus-gunn pupil. not constriction to direct light but does constrcit to consensual light
seen with MS and traumatic optic nerve lesion
no aniscoria
What happens with a CNIII lesion?
hutchinson pupil: dilated pupil that doens’t constrict to direct or consensual light. tested with pupillary light reflex. usually deviated laterally and down due to unobosed CNIV and VI
ptosis and aniscoria present
seen with saccular aneurysm (congenital), usually of the posterior communicating artery, uncal herniation, or ischemic infarction due to DM
What is the argyll-robertson pupil?
irregular pupil which constricts to near vision but not to light. lesion in part of the pretectum. seen in tertiary syphillis. irregular pupil due to co-existing irirtis
What is horner’s syndrome?
ptosis, miosis, anhydrosis, and enophthalmos due to loss of sympathetic input to the eye.
Where are potential lesions that cause Horner’s syndrome?
hypothalamus, brain ste,, cervical spinal cord, intermediolateral cell column at T1-T2, superior cervical ganglion, post-ganglionic sympathetic nerve traveling along the internal carotid artery and trigeminal nerve.
What are the most common causes of CNIV damage? Clinical manifestations?
head trauma. Manifestation is usually double vision, esp. when reading or descending stairs. Patients get a head tilt away from the affected eye to compensate for the dysfunction of the superior oblique
What is trigeminal neuralgia?
tic doloroeaux: recurrent paroxysms of sharp, lancinating pain in the distribution of the 2nd or 3rd divisions of the trigeminal nerve. Usually seen in older individuals, possibly due to repeated trauma to the tigeminal nerve by pulsating bood vessels near the nerve.
How do you treat trigeminal neuralgia?
carbamazepine, phenol nerve blocks, surgery
When do you see abducens nerve problems?
head trauma, ischemic infarction with DM, diffusely raised intracranial pressure. In the setting of raised intracranial pressure, the 6th nerve palsy is a false localizing sign.
What is one important eye-related risk of bell’s palsy and what is treatment?
because patients can’t close one eye, they sometimes experience corneal ulceration
treatment includes a course of corticosteroids
What is the difference between cochlear and retro-cochlear sensori-neural hearing loss?
cochlear: good speech discrimination
retro-cochlear: poor speech discrimination
What nucleus is involved in the jaw jerk reflex?
mesencephalic nucles of CNV
What is one thing that is unique about a CNIII lesion caused by diabetic infarctions?
parasympathetic fibers are on the outside oft he nerve, so pupil constriction is spared even though extraoccular muscle movements aren’t
What is Meniere’s syndrome?
syndrome of recurrent episodes of hearing loss, tinnitis, and vertigo with each episode lasting 30 minutes to several hours.
What is glossopharyngeal neuralgia? Treatment?
syndrome of recurrent paroxysms of sharp, lancinating pain in the posterior pharynx. Like with trigeminal neuralgia, treat with carbamazepine
