Ocular Manifestations of Neurologic Disease

Question 1

Give 3 clinical features of CN 3 aberrant regeneration

Answer 1

1. Elevation of the upper lid (pseudo von Graefe’s sign) on attempted adduction or depression.
2. Adduction or retraction of the globe on attempted depression or elevation
3. Absent pupillary light reaction with pupil constriction on attempted adduction.

Question 2

What is a Carotid-Cavernous Fistula?

Answer 2

An abnormal communication between the ICA, or its branches, and the cavernous sinus.
Classifications:
1. Etiology: Spontaneous vs. Trauma
2. Angiographically: Direct vs. Dural
3. Hemodynamically: High flow vs. Low flow
*Classic = Direct, High-flow from trauma

Question 3

Give some clinical features of a CC Fistula

Answer 3

Diplopia
Ophthalmoplegia
Orbital Bruit
Arterialized conjunctival and episcleral vessels
Edema and chemosis of lid and conjunctiva
Elevated IOP

Question 4

What characteristic finding on neuroimaging is classic of a CC Fistula?

Answer 4

Engorged superior ophthalmic vein

Question 5

What is Tolosa-Hunt Syndrome?

aka Painful Ophthalmoplegia

Answer 5

Idiopathic granulomatous inflammation of the CS with no known systemic disease associations and no lesions outside the CS.

• Lab work is usually normal
• MRI will show the characteristic granulomatous soft tissue density

Question 6

What is the most common malignancy to invade the CS by direct extension?

Answer 6

Nasopharyngeal Carcinoma

• Originates in the nasopharynx, erodes the neighboring bone and infiltrates the CS
• Must always be considered when a patient presents with a painful ophthalmoplegia.

Question 7

The parasympathetic pupillary fibers enter the orbit via which cranial nerve? What about the sympathetic pupillary fibers?

Answer 7

Parasympathetic fibers enter the orbit with CN 3 (inferior division) then synapse at the ciliary ganglion. They enter the eye via the short ciliary nerves.
The sympathetic fibers enter the CS with the internal carotid artery, join the trigeminal ganglion, pass into the orbit with the nasociliary nerve and enter the eye via the long ciliary nerves.

Question 8

Tonic pupils (neuropathic or idiopathic - adie’s) results from a lesion located where along the efferent pupillary pathway?

Answer 8

@ the ciliary ganglion and the postganglionic fibers.

Question 9

Typically what will a patient a patient with Adie’s tonic pupi/s come in complaining of?

Answer 9

20-40 yo female with unilateral blurred near vision and asymptomatic anisocoria. Often these patients will report a mild upper respiratory infection.
Findings:
Young woman 20-40 yo
Unilateral Blurred vision
Asymptomatic anisocoria
Mild Upper respiratory infection
Dilated pupil with poor rxn to light and near
Segmental pupil response with oval shape
Slow/Tonic near response greater than light response
Variable accommodation
Pupil becomes smaller over time
2nd eye involvement over time
Diminshed deep tendon reflexes of the knee and ankle
Diminished corneal sensation in affected eye

Question 10

What are the clinical findings in Horner’s Syndrome?

Answer 10

Clinical Triad: Miosis, Ptosis, facial anhidrosis

Other findings: Ocular hypotony, increased amps of accommodation, heterochromia

Question 11

What are the 4 general classes of eye movements that make up the SUPRA-nuclear ocular motility system?

Answer 11

1. Smooth Pursuits
2. Saccadic
3. Vestibular-Optokinetic
4. Vergence
   * Typically a lesion affecting the supranuclear motility system rarely causes a complaint of diplopia.

Question 12

Where is the cortical control of the smooth pursuit system arise?

Answer 12

Parieto-occipito-temporal junction (aka the P-O-T mesencephalic pathway).

• Control is Ipsilateral: The left POT pathway controls smooth pursuits to the left.
• Signal to begin a smooth pursuit begins in the paramedian pontine reticular formation (PPRF).

Question 13

Typically disorders of the smooth pursuit system will display a series of small saccades that replace the long smooth pursuit. If a patient exhibits small saccades to the left during pursuit testing, then the lesion is located in which hemisphere?

Answer 13

Left

Question 14

Where do non-foveal saccadic eye movements originate?

Answer 14

Contralateral frontal eye fields (Brodman’s Area 8) and the superior colliculus.

• Foveal saccadic eye movements are initiated in the occipito-pariental junction)
• Stimulation of the LEFT Brodman’s Area 8 will produce a saccadic eye movement to the RIGHT

Question 15

What is the role of the PPRF (paramedian pontine reticular formation)?

Answer 15

Conjugate ipsilateral horizontal gaze movements.

*vertical saccadic movements require bilateral cortical mediation

Question 16

A patient with a Supranuclear palsy will usually show loss of mobility in which direction first?

Answer 16

Downgaze (along with immobility of the neck)

*Horizontal and upgaze movements are lost later.

Question 17

Progressive supranuclear palsy (seen in patients with Parkinson’s) displays what mobility deficits?

Answer 17

Decreased convergence, superior gaze immobility and saccadic initiation delays.

Question 18

The vestibulo-optokinetic reflex is initiated where?

Answer 18

Sensory cells within the semi-circular canals.

• the sensory cells detect motion, whether due to gravity or acceleration, in their given plane.
• This system acts to produce an eye movement that is equal and opposite to quick, short-lived head movements.
• The optokinetic system stabilizes the image during prolonged rotation of the head (i.e. ice skater spinning for 30 secs)

Question 19

Information from the right semicircular canal is transmitter where?

Answer 19

to the right vestibular nuclei –> right PPRF –> R CN VI nuclei –> RLR + LMLF (then to the LCNIII –> LMR)

Question 20

How can you examine for vestibular nystagmus/imbalance?

Answer 20

Vestibular imbalance - Hold patients head still and have them fixate a distance target –> note any type of nystagmus-like movements (if difficult to detect, use and ophthalmoscope to visualize the ONH for any quivering)
*Vestibular Nystagmus is accentuated when a fixation target is removed (fog patient with high plus lenses - if still no nystagmus then have the patient shake their head side to side for 10 secs and then stop - look for residual jerk nystagmus. Do this again in the vertical direction.

Question 21

When “caloric testing” to evaluate the integrity of the labyrinthine system - if cold water is introduced into the left external auditory canal, in which direction would the resultant fast phase of the jerk nystagmus be directed?

Answer 21

Cold Water: The fast phase would be in the direction OPPOSITE to the ear tested - in this case it would be to the right.

• If warm water was introduced then the fast phase would be in the SAME direction.
• mnemonic = COWS (Cold = opposite, Warm = same)

Question 22

What is the most likely cause of an INO in a young woman?

Answer 22

MS

*If the patient is older than 50, then vascular occlusive disease is considered.

Question 23

What is the most likely cause of a bilateral abducens palsy?

Answer 23

Neoplasm (never caused by infarction)

*2nd most common cause is MS

Question 24

What is Gradenigo’s Syndrome?

Answer 24

6th nerve palsy + ipsilateral facial pain + (possible deafness) = Gradenigo’s.
*Due to inflammation, infection or tumor near the mastoid process.

Question 25

What muscles make-up the eyelid and which cranial nerves innervate them?

Answer 25

Orbicularis Oculi - CN 7 (facial - zygomatic and temporal): closing of the eyelid
Levator palpebrae superioris - CN 3 (superior branch): Opening of the eyelid
Muller’s Muscle - Sympathetics: assists in opening the eyelid and maintains upper eyelid tonus
*Sensory branches of the CN 5 (V1 - supraorbital branch) also innervate the eyelid

Question 26

What is the average vertical height of the palpebral fissure?

Answer 26

10mm

Question 27

What is the normal position of the globe within the socket? (Based on Hertel Exophthalmometry)

Answer 27

15 - 24mm

Question 28

What is a normal MRD1 measurement? MRD2?

Answer 28

Marginal reflex distance 1 is measured from the pupillary light reflex to the margin of the upper lid = 4-5 mm
*MRD2 is measured from the light reflex to the lower lid = 5-6 mm

Question 29

Why does Myasthenia Gravis not affect the pupil?

Answer 29

Because MG is a disorder of skeletal muscle only and the pupil is controlled by smooth muscle fibers.

Question 30

When suspecting MG in a patient with a ptosis, why does applying an icepack work?

Answer 30

By lowering the temp of the eyelid to 29 deg C, the amount of ACh is increased and the release of the enzyme that degrades ACh decreases.
*Need to place the icepack on the lid for 2 minutes.

Question 31

Explain the “Cogan’s Lid Twitch” that is often seen in patients with MG

Answer 31

When the patient looks down and then back to primary gaze, the ptotic eyelid will overshoot and slowly drift back to its previous ptotic state back in primary gaze.

Question 32

What is another way to evaluate a patient in the exam room for MG when they present with a minimal ptosis? (other than the icepack test)

Answer 32

Have the patient look up for 1 minute OR have them forcibly blink for 1 minute. This will increase the level of the ptosis if due to MG.

Question 33

What drugs should a patient with MG avoid because it can make the symptoms worse?

Answer 33

Aminoglycosides (gentamycin, tobramycin, neomycin, polymyxin), beta-blockers, phenothiazines, alcohol, quinine derivatives and penicillamine.

Question 34

What is Dalrymple’s sign? Von Graefe’s sign?

Answer 34

Dalyrmples - Lid retraction 2/2 to Grave’s Disease

Von Graefe’s - Lid lag in downgaze 2/2 Graves

Question 35

What are the characteristic findings of Dorsal Midbrain Syndrome (Parinaud’s Syndrome)?

Answer 35

Bilateral lid retraction (Collier’s Sign) with no retraction in downgaze. Mid-dilated pupils fixed to light but reactive to near, supranuclear upgaze paresis w/ retraction-convergence nystagmus, convergence dysfunction.

• Typically due to a tumor of the pineal gland.
• AKA Sylvian Aqueduct Syndrome

Question 36

What is the most common cause of optic disc swelling in the elderly?

Answer 36

AION (anterior ischemic optic neuropathy)

• Sudden, painless, unilateral loss of vision/VF 2/2 infarction at the level of the lamina cribosa
• Other signs: Reduced color consistent with vision reduction, RAPD, altitudinal defect, pale - swollen ONH often with peripapillary hemes in a sectoral pattern. Often the superior pole is more affected (3:1). Swelling/hemes take 2-8 weeks to resolve with little/no improvement in VA.
• Hypertension associated in 41% of cases

Question 37

What is Foster-Kennedy Syndrome and how can you differentiate it from a AION?

Answer 37

Foster-Kennedy Syndrome is a large subfrontal mass in the brain that causes optic nerve compression in one eye and ONH swelling in the other eye.
*One eye will display a optic atrophy while the other eye will be edematous without VA loss.

Question 38

What was conclusion of the ONTT (optic neuritis treatment trial)?

Answer 38

Determined the efficiency of systemic steroids for idiopathic optic neuritis.

• Conclusion: Oral steroids alone have no benefit and these patients had a higher reoccurrence rate.
• Patients treated with IV steroids followed by oral steroids had faster visual recovery but had no significant advantage long term vs. oral placebo.

Question 39

In patients presenting with a suspected optic neuritis - what would you expect on a color desaturation test?

Answer 39

The color desaturation test is usually disproportionate to that of visual acuity, with a notable desaturation to red test objects.

Question 40

Is there a RAPD present in patients with papilledema?

Answer 40

No - papilledema is almost always bilateral although it may be asymmetric. Vision is typically good and VF may show enlarged blindspots.

• patient may be asymptomatic or may experience neurologic symptoms such as headaches, vomiting, nausea, TIAs, amaurosis fugax.
• Some patients may experience bilateral abducens palsies (compression at the level of the clivus)

Question 41

Does the presence of a SVP help r/o papilledema?

Answer 41

Yes - the presence of a SVP indicates that the ICP is below 200 mm H2O. 20% of patients however do not have a SVP….so the presence is helpful to rule against increased ICP but the absence is of limited use.

Question 42

What is the most common cause of pseudodisc swelling?

Answer 42

ONH drusen (75%)
*ONH drusen are usually bilateral and familial. They may cause anomalous branching of the disc vessels and usually associated with small ONH.

Question 43

What are some other causes (besides ONH drusen) of pseudopapilledema?

Answer 43

High hyperopia with disc hypoplasia, tilted discs, myelinated NFL and peripapillary choroidal neovascular membranes.

Question 44

Name some causes of toxic optic neuropathy

Answer 44

Methanol, streptomycin, chloramphenicol (antibiotic), ethylene glycol (anti-freeze), ethambutol (antimycobacterial drug for TB) and lead ingestion.
*Chronic alcohol abuse can lead to a slow progressive retrobulbar optic neuropathy that usually doesn’t present with ONH swelling.

Question 45

What is Leber’s Hereditary Optic Neuropathy?

Answer 45

mitochondrial DNA mutation that affects young men (9:1 vs. females) ages 15-30.

• Severe, rapid, unilateral VA loss, central/cecocentral scotoma. The fellow eye has a similar episode days - weeks later.
• ONH appears mildly elevated with peri-papillary vessel telangiectasia that does not leak on Fl.
• Patient should consult with a cardiologist because of the association with electrocardiographic abnormalities

Question 46

What is considered to be the most important risk factor for a stroke?

Answer 46

Recent research suggests cardiovascular disease (previous thinking was HTN), more specifically atrial fibrillation.

Question 47

What general process is responsible for most cerebral ischemic attacks?

Answer 47

Atherosclerosis - the bifurcation of the common carotid artery into the internal and external carotid are responsible for 90% of ischemic stroke syndromes.

Question 48

What is a “reversible ischemic neurologic deficit”?

Answer 48

A TIA that produces symptoms that last longer than 24 hours. Typically a TIA will produce focal visual, motor, sensory loss for 2-15 minutes but may last up to 24 hours.

Question 49

What is the risk for a stroke after an episode of TVL (transient vision loss)?

Answer 49

40%

Question 50

If a patient presents with bilateral symptoms of a TIA - where is the suspected occlusion?

Answer 50

Vertebrobasilar system - because the basilar artery combines the 2 hemispheres

Question 51

Which retinal nerve fibers sweep into the contralateral optic nerve for a short distance before traversing the optic chiasm?

Answer 51

Inferior nasal fibers (von Willebrand’s loop)

Question 52

What chemical in hot dogs, bacon, ham and salami might trigger a migraine?

Answer 52

Sodium nitrite.

Question 53

What type of headache is considered the most severe by patients?

Answer 53

Cluster - occur in clusters that last 2 -12 weeks, lasting 30-120 minutes and may occur several times a day. Patient may go into remission for months to years after the cluster period. Patients are usually awakened by the headache in the middle of the night.
*Other symptoms include: unilateral facial sweating, lacrimation, nasal congestion and a ptosis and miosis.
Males 5:1, 20-40 yo, heavy smokers/drinkers

Question 54

Which type of headache is thought to account for 90% of all chronic, recurrent headaches?

Answer 54

Tension (Muscle contraction) - steady, nonpulsatile HA due to chronic contraction and subsequent spasm of the muscles of the face, head and neck. Pain is usually diffuse.