Study
Review All
Quiz!
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If your patient has an inferior oblique problem, what kind of diplopia is expected? How about superior oblique? |
Vertical (both IO and SO) |
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Which muscle(s) is/are suspected with horz diplopia worse at far? |
LR |
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Which muscle(s) is/are suspected with horz diplopia worse at near? |
MR |
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Which muscle(s) is/are suspected with vert diplopia worse at far? |
IR or SR |
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Which muscle(s) is/are suspected with vert diplopia worse at near? |
IO or SO |
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What motor nerve is assoc w/ the iris sphincter? |
CN III |
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What motor nerve is assoc w/ the levator? |
CN III |
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What motor nerve is assoc w/ the orbicularis? |
CN VII (facial) |
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What motor nerve is assoc w/ the dilator of the iris? |
oculosympathetic branches |
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What motor nerve is assoc w/ Muller's muscle? |
oculosympathetic branches |
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Your pt complains of monoc diplopia. What test would you use to R/O a cortical problem? |
Pinhole test |
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Place in order of prevalence of palsies (most to least): CN III, IV, VI. |
1. CN VI (abducens) = 3x Mnemonic = "ATOM" |
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What is the only CN nucleus with subnuclei? |
CN III |
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Origin of CN III? |
Oculomotor nuclei and Edinger Westphal nuclei |
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CN III superior branch innervates which muscles? Inferior branch? Parasympathetic fibers? |
SR, levator = superior |
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T/F - 3rd nerve palsies involve a partial ptosis. |
False - full ptosis |
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Your pt presents with full ptosis, mydriasis, and an eye that goes down and out underneath the ptosis. He also has eye pain. You suspect... |
CN III palsy |
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3rd nerve palsies involve a (miotic/mydriatic) pupil. Why? |
Mydriatic b/c CN III innervates sphincter of iris. If sphincter not working, then unable to close pupil, most noticeably in bright light. |
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Your left 3rd nerve palsy pt also has amblyopia OD. How will this patient present? |
Since pt prefers fixation with OS, the left lid will be elevated and will raise OS, thus OD will have lid retraction and hyper. |
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T/F - 3rd nerve palsy does not involve ocular pain. |
False - retro- or peri-orbital pain |
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Your pt has a 3rd nerve palsy, but you're having a hard time isolating CN IV fxn with motility testing. What can you do to check CN IV fxn? |
Look at a vessel on the sclera and see if it rotates to check SO fxn (intorsion). |
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Your patient presents with a full ptosis OS with the eye below going down and out. Pupils appear normal, both in dark and light. You suspect... |
CN III palsy, vascular etiology e.g. DM |
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List causes of CN III in adults, from most prevalent to least. |
1. Undetermined |
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What areas in the brain are suspected to cause CN III palsies? |
- Exit from brainstem |
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List causes of CN III in kids, from most prevalent to least. |
1. Congenital |
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Congenital CN III palsies are associated with what conditions (according to the slide)? |
Amblyopia, aberrant regeneration |
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A central lesion at the nucleus of CN III will result in... |
Bilateral ptosis (or no ptosis), contralateral SR palsy; ipsilateral III palsy; can also have isolated muscle paresis |
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A central caudal CN III subnucleus lesion will affect... |
both levators (bilat) |
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A lesion at the lateral CN III subnuclei will affect... |
Ipsilateral MR, IR, IO |
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A lesion at the medial CN III subnuclei will affect... |
contralateral SR |
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Causes of CN III palsy originating from the nucleus? |
- Infarction e.g. thrombus, emboli (most common) |
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T/F - A nuclear CN III palsy can involve a unilateral dilated pupil. |
False - E-W subnuclei are fused so both sides are affected |
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T/F - A nuclear CN III palsy can involve a unilateral ptosis. |
False - Central caudal subnucleus responsible for both levators |
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T/F - A nuclear CN III palsy can involve an isolated IR palsy? |
True |
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T/F - A nuclear CN III palsy can involve an isolated MR palsy? |
True |
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T/F - A nuclear CN III palsy can involve a bilateral III palsy without ptosis. |
True |
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T/F - A nuclear CN III palsy can involve an isolated SR palsy? |
False |
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A nuclear CN III palsy can involve OD with a normal OS. |
False (b/c central caudal nucleus controls both levators?) |
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What are the syndromes involved with the CN III fascicle lesions? |
Benedikt's, Weber's, Nothangel's, and Claude's |
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Benedikt's involves damage to what structures and what Sx? |
Ipsilateral CN III paresis + ipsilateral cerebellar ataxia (damaged red nucleus and CN III fascicle) |
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Weber's involves damage to what structures and what Sx? |
Ipsilateral CN III paresis, contralateral hemiparesis, possible upper VII motor neuron involvement (damaged corticospinal tract and CN III fascicle) |
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Your pt presents with the whole right side of the body paralyzed and a ptosis OS with the eye under the lid down and out. You suspect... |
Weber's; ipsilateral CN III paresis + contralateral hemiparesis, due to damaged CN III fascicle + corticospinal tract |
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Nothangel's involves damage to what structures and what Sx? |
Ipsilateral CN III paresis, contralateral hemitremor (damaged CN III fascicle + brachium conjunctivum) |
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Claude's involves damage to what structures and what Sx? |
Ipsilateral CN III paresis, ipsilateral cerebellar ataxia, contralateral hemitremor (damaged CN III fascicle, red nucleus, and brachium conjunctivum) Basically Benedict's + Nothangel's |
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Your pt presents with a full ptosis + down and out OS, uncoordinated limb movements of the left side, and tremors on the right side. You suspect... |
Claude's Ipsilateral CN III paresis, ipsilateral cerebellar ataxia, contralateral hemitremor (damaged CN III fascicle, red nucleus, and brachium conjunctivum) |
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T/F - Thiamine deficiency can cause CN III fascicle damage. |
False - causes nuclear CN III damage |
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T/F - Demyelination can cause CN III fascicle damage |
True |
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Sx of uncal herniation? Why? |
Pupil enlarges and unreactive to light (= Hutchinson's pupil), pt becomes comatose Due to CN III palsy caused by supratentorial mass pushing uncus of temporal lobe against CN III |
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What are the causes of CN III problems in the Sub-arachnoid space? |
Posterior communicating artery (PCA) aneurysm, meningitis, tumors, trauma |
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You must R/O ____ if you see a full ptosis with a dilated pupil because it may be fatal. |
PCA aneurysm |
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A PCA aneurysm can cause a (dilated/miotic) pupil. Why? |
Pushes dorsomedial aspect of CN III, where pupillary fibers lie. |
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In a PCA aneurysm, the pupil takes up to ___ days to become dilated. |
3-5 |
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Most common cause of isolated, non-traumatic CN III palsy with pupil involvement... |
PCA aneurysm |
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T/F - PCA aneurysms present w/ pain. |
True - almost always (retro-orbital or peri-orbital) |
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T/F - PCA aneurysms rarely have isolated pupil involvement. |
True |
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PCA aneurysms involve EOMs within ___ to ___ (what time frame?). |
hours to days |
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T/F - Cavernous sinus dz can involve proptosis. |
True |
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Your pt has a full ptosis OS with the eye under the lid down and out, pupils normal. You also see engorged, corkscrew-like conjunctival vessels and proptosis. You suspect ____. Why? |
Cavernous sinus dz causing CN III palsy |
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Causes of orbital-related CN III palsies? |
Tumor, inflammation, trauma |
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Your pt has a Hx of assault (he was punched in the left eye), and has pain, proptosis, and conj chemosis. On EOM testing, all but the the MR, IO, and IR work fine. You suspect... |
Selective trauma to inferior branch of CN III. |
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EOM fibers are in the (outer/inner) part of CN III. |
inner |
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T/F - The pupil is typically not spared in ischemic-vascular CN III palsies. |
False - typically spared (62-83%) |
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T/F - Pupil-sparing CN III palsies can involve pain. |
True |
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Pupil sparing CN III palsies resolve after ___ months (with/without) aberrant regeneration. |
3-4, without |
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T/F - Pupil sparing CN III palsies typically resolve on their own. |
True |
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Describe the mechanism of vasculoplastic palsy. |
Thickening/hyalinization of nutrient vessels or decr perfusion at vascular border of nerve, ischemic demyelinization of segment of nerve, eventual remyelinization and recovery |
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T/F - Vasculopathic CN III palsies that spare the pupil show diffuse pattern of EOM paresis. |
True |
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T/F - Aneurysm-related CN III palsies that spare the pupil show diffuse pattern EOM paresis. |
False - show focal (superior branch) pattern of EOM paresis Pupil fibers are in the inferior branch |
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T/F - Ophthalmoplegic migraines first appear in adults 20-30 yrs old. |
False - children under 10 yrs old |
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Your 8-yo pt presents w/ nausea, periorbital pain, OS down and out with full ptosis, and severe headache on the left side of his head. Pupils are normal. You suspect... |
Ophthalmoplegic migraine |
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Describe the progression of recovery in ophthalmoplegic migraine. |
ptosis first, then pupils, then EOMs |
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CN palsies of ophthalmoplegic migraine - list from most to least frequent CNs affected. |
CN III, VI, IV "OAT" - Oculomotor, Abducens, Trochlear |
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T/F - Most cases of Ophthalmoplegic migraine spare the pupil. |
True - 2/3rds of cases, suggests vascular etiology (int carotid ischemia?) |
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T/F - Ophthalmoplegic migraine does not respond to steroids. |
False - Ophthalmoplegic migraines do respond to steroids |
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T/F - Aberrant regeneration is possible in ischemic-vascular related events. |
False - aberrant regeneration never in ischemic-vascular events |
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Etiologies of aberrant CN III regeneration? |
- Acute CN III palsy (trauma, aneurysm, tumor) |
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Possible mechanisms of aberrant regeneration? |
1. Misdirection of sprouting axons from one structure to another |
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Describe Pseudo Von Graefe's sign. This is caused by... |
Pt looks down, lid goes up; caused by aberrant regeneration of IR fibers going to LPS |
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Describe Lid synkinesia. This is caused by... |
Eye adducts, lid shoots up. When eye goes out, lid goes down. Caused by aberrant regeneration of MR branch redirecting to superior branch |
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T/F - Tonic pupil is a sign of aberrant regeneration. |
True |
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T/F - Monocular horiz OKN is a sign of aberrant regeneration. |
False - vert |
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Aberrant regeneration with no prior Hx of CN III palsy, caused by slow compression of CN III is called... |
primary aberrant regeneration |
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Aberrant regeneration following acute CN III palsy or congenital CN III palsy is called... |
secondary aberrant regeneration |
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In adults, if you see a non-traumatic, isolated CN III palsy, what is the management? |
R/O aneurysm, refer MRI/angiogram STAT (gadolinium contrast, CT or MR angiography) |
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In adults, if you see a pupil-sparing CN III palsy, what is the management? |
Ischemic dz workup: BP, CBC, ESR, oral glucose tolerance test, VDRL/FTA-ABS (syphillis), ANA; STAT CT and/or MRI |
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Your 45 yo pt has a pupil-sparing, complete CN III palsy and a Hx of long-term DM, what is the management? |
- Watch pupil daily for 1 wk to see if it becomes involved (if involvement, refer for MRI) |
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Management of aberrant regen with no Hx of head trauma? |
MRI |
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Management of isolated, acquired, non-traumatic CN III palsy in a kid? |
Order MRI thru neurologist, ped ophthalmologist, or pediatrician |
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With CN III palsy with pain, you should suspect... |
aneurysm |
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CN III palsy in kid, R/O... |
aneurysm |
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CN III palsy with pupil sparing in older pts, think... |
vascular dz |
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CN III palsy with pupil sparing, think... |
ischemic-vascular |
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T/F - Most aneurysms affecting CN III involve the pupil. |
True (86-97%) |
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T/F - Most aneurysms affecting CN III involve pain. |
True - almost always |
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T/F - Most ischemic-vascular problems affecting CN III can involve pain. |
True |
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Your pt has a hyper OD and complains of words going double vertically while reading, and sometimes finds himself reading into the next line of print. You suspect... |
CN IV palsy |
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T/F - CN IV pts tend to hold their reading material down and out to reduce Sx. |
True |
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You expect left SO palsy pts to tilt their head... |
To the right SOTO = Sup Oblique Tilt Opposite |
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CN IV palsy pts have the inability to (extort/intort). |
intort (UA SO) remember "inferior people extort" |
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CN IV palsy pts have an overacting ___ muscle. |
IO (ipsilateral) |
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Why is an RSO palsy worse on right head tilt? |
The primary depressor on right head tilt is the SO, but since the SO is underacting, will see a more hyper OD (see slide of smiley face) |
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How would bilat CN IV palsy present if you had them gaze to either side or tilt on either side? |
Rhyper in left gaze and right head tilt (R-L-R) Lhyper in right gaze and left head tilt (L-R-L) |
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Upon EOM testing you determine your pt has a CN III palsy. What are your Park's 3-step findings? |
Trick question - Park's works only if one EOM is involved. |
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On Park's 3-step, you find a right hyper, worse on left gaze and right head tilt. You suspect... |
RSO palsy (RLR - think of the first letter as the side affected, hence LRL would be LSO palsy) |
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In your CN IV palsy pt, you get 6 left hyper, thus vertical fusional amps are expected to be... |
D) 10 BU, 15 BD OS |
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On the bilateral maddox rod test, you place (BU/BD) prism over the (paretic/nonparetic) eye. |
BD, nonparetic |
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On the bilateral maddox rod test, if the patient sees the line from his RE tilted to the left, you expect his RE to be (extorted/intorted). |
extorted (line is intorted) |
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Etiology of CN IV palsies and their percentages? |
Neoplasm/aneurysm (10%) Now I Understand Trochlear palsies |
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Causes of CN IV palsies in children, from most to least prevalent? |
Congenital (67%) |
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Name the 4 syndromes assoc w/ CN IV. |
Nuclear-fascicular |
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T/F - Nuclear-fascicular CN IV (Midbrain) lesions usually unilateral. |
False - asymmetric, bilat |
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On your pt you see a hyper LE with a head tilt to the right, and a partial ptosis with miosis on the RE. You also notice that the patient's skin is flushed on the right side. You suspect ____. Why? |
Lesion at right brainstem affecting right CN IV nucleus (thus UA LSO) and right sympathetic branches (thus Horner's). Remember SO is controlled by contralateral CN IV nucleus - right CN IV nucleus innervates left SO. |
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T/F - A CN IV nuclear-fascicular lesion at the brainstem would affect L-N dissociation. |
True |
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Where do the CN IV fibers decussate? |
Anterior medullary vellum, on dorsal surface of brainstem |
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In sub-arachnoid space, a head injury can result in compression of CN IV where? |
at tentorial edge |
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How can disc edema occur with CN IV palsies? |
Incr intracranial pressure at subarachnoid space |
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A pinealoma in the sub-arachnoid space can cause this CN palsy. |
CN IV |
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CN III palsies are typically (severe/moderate/mild) head trauma, while CN IV palsies are typically (severe/moderate/mild) trauma. |
severe = CN III |
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Contusion of the (dorsal/ventral) midbrain tend to cause CN IV palsy. |
dorsal (remember how CN IV exits dorsal midbrain and wraps around to the front) |
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What is the problem with assessing orbital CN IV palsies? |
Hard to assess whether it is really a nerve cause vs tendon, trochlea, or muscle. |
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Why is CN IV susceptible to injury? |
long intracranial course |
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T/F - Sphenoid bone fractures is a possible cause of CN IV palsy. |
True |
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Peak incidence of CN IV palsies (decades)? |
4th-5th decade |
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T/F - CN IV palsy can be associated w/ vascular dz. |
True - HTN, DM, arteriosclerosis, temporal arteritis |
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T/F - Congenital CN IV palsy tends to be bilat. |
False - unilat |
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T/F - 10 degrees or more on the double maddox rod test indicates bilat involvement. |
True |
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You see an isolated non-traumatic CN IV palsy with large vert amps, confirmed w/ old photos. Dx? Mx? |
Congenital CN IV palsy, Mx = no further eval needed |
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Mx of 25-yo non-traumatic CN IV palsy with normal vertical amps? |
R/O ocular myasthenia, send for MRI Do this for 20-40 yo |
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Mx of 60-yo non-traumatic CN IV palsy? |
Ischemic-vascular workup Do this for 40-65 yo |
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Your pt complains of horz double vision when looking at street signs and a right eye that turns in. You notice his head is turned to the right. Dx? |
R CN VI palsy |
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In your right CN VI palsy pt, you expect the (exo/eso) to get worse when he looks to the (right/left). |
eso, right |
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How do you DDx ocular myasthenia gravis vs CN VI palsy? |
myasthenia is transient, worse when tired |
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By looking at the eyes, how you do DDx thyroid eye dz vs CN VI palsy? |
thyroid eye dz = see lid retraction |
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How do you DDx Mobius syndrome vs CN VI palsy? |
Mobius = also see CN VII affected thus see reduced facial tone |
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Etiologies of CN VI palsies in adults? |
Undetermined (21-32%) |
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Most likely cause of CN VI palsies in young adult/middle age? |
Mass lesions |
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Causes and prevalences of CN VI palsy in children? |
Neoplasm 40% |
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Where is CN VI most vulnerable? |
Brainstem (Pons), fascicle, sub-arachnoid space, petrous apex (temporal bone), cavernous sinus, orbit |
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What nuclei is CN VI close to (at the level of the pons)? |
V, VII, VIII |
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T/F - CN VI is close to the cerebellum. |
True |
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Why is it possible to have both a CN VI and VII palsy in a central lesion at the level of the pons? |
VII fibers loop around VI nucleus |
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Lesion at MLF at the level of the lower pons will cause... |
Ipsilateral INO |
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Lesion at the PPRF at the level of the lower pons will cause... |
Ipsilateral horz gaze paresis |
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Lesion at the oculo-sympathetic nucleus at the level of the lower pons will cause... |
ipsilateral horner's |
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Lesion at the pyramidal tract at the level of the lower pons will cause... |
contralateral hemiparesis |
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Pontine glioma can cause progressive damage of these CNs... |
V, VI, VII, VIII Remember these are CNs within the Pons! |
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Your pt complains of diplopia at distance, RE turned in, and hemiplegia of the left side. Dx? Why? |
Raymond's. Lesion at ventral pons affecting VI fibers + corticospinal tract leading to VI palsy & contralat hemiplegia |
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Describe Millard-Gubler's syndrome. |
Fascicular syndrome at ventral pons causing Raymond's (VI palsy + contralat hemiplegia) and VII palsy |
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Name the fascicular syndromes of CN VI. |
Raymond's, Millard-Gubler, Foville's |
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Describe Foville's |
Anterior inferior cerebellar artery infarct affecting pontine tegmentum (CN VI fascicles + olivary nucleus) |
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T/F - CN VI palsy involves the lowest degree of head trauma vs III & IV. |
True |
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How does head trauma cause a CN VI palsy? |
1) Fracture of petrous bone - lateral |
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How can the sub-arachnoid space be involved in a CN VI palsy? |
Incr intracranial pressure causes stretching of CN VI with downward displacement of brainstem. Causes bilat disc edema, incr esodeviation, nausea, HA. |
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Inflammation of the meninges and tip of the petrous bone describes... |
Gradenigo's |
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Gradenigo's can cause these CN palsies... |
V, VI, VII, VIII Note these are all Pons-level CNs |
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CN V, VI, VII, and/or VIII palsies after an ear infection in a child makes you think... |
Gradenigo's |
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T/F - Nasopharyngeal carcinomas are more common in caucasians. |
False - Asians |
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Nasopharyngeal carcinomas present with... |
decr tearing (V nerve), facial pain, can block eustachian tube and cause "clogged" ear |
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Cerebellopontine angle tumors involve these CN palsies and what Sx? Locaton? |
CN V, VI, VII, VIII (these are all Pons CNs); ataxia, papilledema At petrous apex |
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For CN __ palsies, you have to consider Pontine Gliomas, Gradenigo's, and Post-viral infections in children. |
VI |
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T/F - Consider Gradenigo's for CN VI palsies age 15-35. |
False - consider MS in that age range Gradenigo's - considered in children |
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T/F - Nasopharyngeal carcinomas, meningiomas are considered in CN VI palsies age 35-55. |
True |
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T/F - In pts over 55, consider ischemic vascular, giant cell arteritis as causes of CN VI palsy. |
True |
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You have an 8yo pt coming in with non-traumatic CN VI palsy - Mx? |
Aggressive management to R/O glioma. Also R/O post-viral infection. Monitor other cases q2wks for improvement. If neuro signs or no improvement, MRI. |
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Neuroimaging is indicated for non-traumatic VI if... |
- accompanying neuro signs |
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Mx of non-traumatic VI if pt has papilledema? |
Neuroimaging |
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You've followed your non-traumatic CN VI palsy pt for the past month, but the palsy is still present. Mx? |
Continue to f/u; if does not resolve in 2-6 mos (total 3-6 mos) then neuroimaging |
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How often to f/u for vascular-ischemic related CN VI palsies? |
every 6 weeks |
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T/F - Meningeal dz or increased intracranial pressure will most likely cause bilat VI paresis. |
True |
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It is most important to R/O this cause of CN VI in kids... |
glioma |
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It is most important to R/O these causes of CN VI in older pts... |
ischemic-vascular dz or carcinoma |
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What important sign in the eye should you watch for in CN VI palsies? |
disc edema |
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What is Hutchinson's pupil? |
Pupil enlarges and unreactive to light, seen in Uncal Herniation. |
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Ophthalmoplegic migraines respond well to this drug. |
Steroids |
