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1 Neuro Eye Diseases > MT2 > Flashcards

MT2 Flashcards

1
Q

4 questions of double vision

A
  1. Does it go away when one eye is covered?
  2. Is it horizontal or vertical?
  3. Is it worse when you look in a certain direction?
  4. Greater at distance or near
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2
Q

Causes of monocular diplopia

A

Glasses prob
Bifocal seams
Astigmatism Polycoria
cataracts due to asymmetry

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3
Q

What muscles do you suspect are causing a horizontal or vertical diplopia?

A

Horizontal- 4 muscles. MR and LR
Vertical- 8 muscles. SO, IO, SR, IR

To narrow down further, ask if it gets worse when looking to the left or right. Can narrow down to 2 or 4 more muscles now.

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4
Q

Thermostat vs dinner plate muscles

A

Thermostat- IO

Dinner plate- SO

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5
Q

3 causes of diplopia and the most common one

A
  1. Optical causes (not common)
  2. VF defects
  3. Ocular motility issues (most common)
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6
Q

Hemifield Slide phenom

A

Dense bitemporal hemi. Causes a sensory diplopia.

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7
Q

Palinopsia

A

Homo hemi. Brain substitutes visual images from the temporal lobe- moose on car.

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8
Q

Fast and slow eye movements

A

Fast- saccades. 300-700 deg/sec

Slow- pursuits. 30-40 deg/sec

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9
Q

Reading card positions

  1. Held to extreme left or right?
  2. Card held down and tilted?
  3. Card held down and head leaned back?
  4. Card pushed away?
  5. Card held close?
A
  1. Held to extreme left or right? Abduction deficit. Held closer to the normal eye. or hemi.
  2. Card held down and head tilted?
    SO palsy, held away from paretic muscle.
  3. Card held down and head leaned back?
    Low bifocal, ptosis, A or V, CL problem
  4. Card pushed away?
    Constricted field, presbyopia, hyperopia
  5. Card held close?
    Myopia
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10
Q

Red glass test. Ask pt to look in different gazes? How do you know which muscle is involved?

A

The muscle involved is always in the eye the corresponds with the color of the light that is further away from fixation.

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11
Q

When can you do the bielchowsky head tilt test?

A

With red glass test. Have the pt tilt their head and tell you when the spread of the colors increases.

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12
Q

Maddox rod is a very sensitive test for determining what type of diplopia

A

Vertical

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13
Q

___ is the best way to test for cyclodeviations

A

maddox rod in a trial frame. Determine whether its ex or in based on how the top of the eye lines are rotated

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14
Q

Pt has CN palsy and doing maddox rod testing

A

Imagery will shift as pt looks up and down. Because as the pt looks down, the good eye will depress more than the paralyzed eye.

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15
Q

Tell the patient to look left.

pathway in brain that lets this occur

A

Corticotectal –> pons –> left PPRF –> CN 6 to contract to the LLR

At the same time, the yoke muscle is directed to contract by a small signal from the left PPRF –> MLF –> contralateral CN III that serves RMR

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16
Q

If the patient can’t intort, how will it look on maddox rod testing?

A

Will show an excyclorotation bc pt can’t intort.

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17
Q

PPRF

MLF

A

Paramedian pontine reticular formation

Medial longitudinal fasiculus

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18
Q

What is the problem in a gaze palsy?

A

Information can’t leave the PPRF to go to the R and L subnuceli. Therefore, pt can’t look in a certain gaze.

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19
Q

What condition causes a gaze palsy?

A

Fovilles (Inferior medial pontine syndrome)

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20
Q

Fovilles (Inferior medial pontine syndrome) location of lesion and results

A

Corticospinal tract.

Left tract lesion? Right hemiplegia, left facial palsy. Inability to move eyes together to the ipsi side.

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21
Q

LSO palsy. Tilting head where helps?

A

Tilt head to the right.

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22
Q

Skew Deviation

A

Non localizable defect in the brainstem causing vertical deviation and neuro problems.

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23
Q

3 types of skew deviations

A
  1. Comitant (OD always higher than OS)
  2. Non-comitant (OD higher on right gaze, OS higher on left gaze)
  3. Alternating (OD higher on right, then OS higher on right)
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24
Q

2 studies looking at Skew deviation

A

(+) for upright-supine CT. (Vertical deviation decreases when supine)

Static ocular counteroll reflex is significantly reduced in skew deviation. Asymmetry provides evidence that disruptions ould be due to utriculo-ocular pathway.

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25
Q

Signs of INO

A

Cannot adduct one eye + abduction nystagmus of the other eye.

Can be subtle. Asymmetry in the saccadic movements. Use OKN to look at saccades during the catch up phase (swing flag the opposite direction)

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26
Q

INO. Where is the lesion?

A

MLF. Lesion on the right? Signal can still go from the PPRF to the LLR, but can’t go to the MFL –> RMR. Therefore, RMR cannot abduct. and will have OS left gaze nystagmus.

Anterior INO- lesion in midbrain. Cannot converge. Less common.

Posterior INO- lesion in pons. Can converge. More common.

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27
Q

INO vs bilateral INO

A

Unilateral: Due to vascular disease/brainstem infarction, older person, males, sudden onset, 43% also have skew deviation, convergence still present due to posterior (pons) type.

Bilat: Due to demyelinating disease, younger person, males = females, slowly progressive, few with skew, convergence still present due to lesion in pons

28
Q

Bilat INO. Ask pt to gaze right and left. What happens?

A
  • When asked to gaze right, LMR cannot adduct and OD abduction nystag.
  • When asked to gaze left, RMR cannot adduct and OS abduction nystag.
29
Q

Fisher one and a half syndrome on the right side

A

• Lesion involves PPRF and MLF on one side. Ex: on the right. When asked to gaze right, neither eye moves. When asked to gaze left, OD remains forward and OS has abduction nystag.

30
Q

Another name for Paralytic pontine exotropia

A

Acute 1 & 1/2 syndrome

Acute onset of brainstem infarction involve PPRF and MLF. Eventually, exo eye will turn in.

31
Q

Most common brainstem syndromes that cause diplopia

A

INO and BINO

Be careful, INO may look like MR weakness.

32
Q

CN III palsy most likely due to aneurysm at

A

ICA and PCA

33
Q

CN III palsy with pupil sparing vs pupil involving

A

Pupil sparing- Usually due to DM/ vascular disease. Pt will get diabetic work up. Sharp pain at first, then goes away.
Pupil involving- Usually due to aneurysm. 92% specific. Pt will get arteriogram. Much more severe pain with presentation and it persists.

*Watch the pupil for 1 week as it may become involved.

34
Q

See someone 55+ years with pupil sparing CN III palsy. What do you think?

A

GCA. Check for elevated ESR. Medical emergency.

35
Q

Main differences between aneurysmal and ischemic vascular CN III palsy

A
  1. Pain. More severe and persistent with the aneurysm.
  2. Pupil sparing or not? If spared, continue to monitor for a week. May evolve.
  3. Elevated ESR in a patient over 55+ with pupil sparing = GCA/AAION
36
Q

CN III nuclei organization

A

most dorsal part- IR
Below the IR subnucleus is the SR
The most Inferior lateral subnucelus is the MR

37
Q

Claude’s Syndrome (CN III palsy due to lesion at the nucleus)

A

Lesion of the superior cerebellar peduncle.
Midbrain infraction.
Occurs with involvement of red nucelus that catches the fasicular CN III fibers.
Pt will have CN III palsy with contra ataxia and a tremor.

38
Q

Benedikt’s Syndrome (CN III palsy due to lesion at the nucleus)

A

Involvement of the red nucelus and cerebral peduncle and catching the CNIII fasciculus. Pt will have same as Claude’s (contra ataxia and tremor) + contra hemiparesis.

39
Q

Nothnagel’s Syndrome (CN III palsy due to lesion at the nucleus)

A

Same as Benedikt’s + inability to look up with both eyes. Could be due to involvement of brachium conjunctivum.

40
Q

Weber’s Syndrome (CN III palsy due to lesion at the nucleus)

A

Occurs if the lesion catches the fascular portion of CN III and the crus cerebri.

  • Ipsi CN III palsy
  • Contra Hemi
  1. Extrinsic lesions compress crus cerebri and CN III. Operable.
  2. Intrinsic disease, such as pontine glioma, is inoperable. Tx with radiation and chemo.
41
Q

An isolated involvement of a muscle innervated by CN III means the lesion must be ____

A

In the orbit or CN III nucleus.

Ex: IR palsy OD

42
Q

total ipsi CN III palsy without any involvement of the other eye means the lesion cannot be

A

in the CN III nuceli

If the lesion was in the nuclei, the pt would have bilateral ptosis, and contra SR involvement. Pretty rare.

43
Q

Most common and most likely CN III palsy

A

Weber’s syndrome.
Occurs if the lesion catches the fascular portion of CN III and the crus cerebri. Causes Inspi CN III palsy and contra hemi. Can be intrinsic (inoperable) or extrinsic (operable)

44
Q

Subarachnoid Space CN III Palsy

A

As CN III travels through subarachnoid space, it is subject to compression by the uncus.

Bleeding –> Shifts brain down –> Hutchinsons pupil –> CN III palsy

45
Q

5 main causes of cavernous sinus CN III palsy

A
  1. pituitary apoplexy
  2. Sphenoid sinus infection due to mucomycosis, mucocoele, carcinoma
  3. Carotid rupture/GCA
  4. Meninge tumor. Meningioma/neurofibroma.
  5. Tolosa Hunt (Dx of exclusion)
46
Q

What is a pituitary apoplexy

A

Infarction in a vessel of a pituitary tumor. If someone has a sudden onset of CN III palsy with pain, diplopia, and field cut, its pituitary apoplexy. Life threatening.
An enlarging pituitary tumor can compress the cavernous sinus on both sides + internal carotid arteries + chiasm above it, causing bilateral CN III palsy.

47
Q

Difference between pituitary apoplexy and cavernous sinus fistula

A

Apoplexy is life threatening

Cavernous sinus fistula is sight threatening, not life threatening.

48
Q

THS

A

Idiopathic granulomatous inflammation in the cavernous sinus and SOF. dx of exclusion. Painful, may have horners, recurrent attacks, proptosis. Do 48 hour prednisone test (usually get better and CN abnormalities improve)
-Contrast enhanced MRI is modality of choice

49
Q

3 P’s of cavernous sinus syndrome

A

Pain, proptosis, paralysis

50
Q

The pupil in cavernous sinus syndrome can be -

A

Dilated from CN III palsy
Small from Horners
Mid position
Normal (spared)

51
Q

3 fates after CN III palsy

A
  • Remains permanently fixed and dilated
  • Returns to normal (aberrant regeneration)
  • Becomes light-near dissociated pupil (pseudo AR)
52
Q

Aberrant Regeneration of CN III 6 signs

A
  1. Pseudo VG (when pt looks down, the lids go up)
  2. Lid dyskinesis (when MR is stimulated, the lid will go up. When MR is inhibited, lid goes down)
  3. Light- near dissociation
  4. Retraction of the once paretic eye on vertical gaze
  5. Adduction of the once paretic eye on vertical gaze
  6. Monocular vertical OKN responses are suppressed iin the eye with former palsy
53
Q

Etiology of Aberrant regeneration

A

Aneurysm, trauma, tumor
NEVER due to DM !!!!!!!!!!!!!!!

*reorganization of the motor pool on a brainstem basis

54
Q

Appearance of someone with R SO palsy

A

Chin depressed
Right head turn
Left head tilt ** Most reliable

55
Q

SO action

A

Intort, depress, abduction

56
Q

When the head is tilted to the left, which muscles of the left eye cause intorsion and which muscles of the right eye cause extortion?

A

OS: LSO and LSR intort
OD: RIO and LIR extort

57
Q

Right CN 4 palsy increases hyper when

A

On left gaze, right head tilt

58
Q

Left CN 4 palsy increases hyper when

A

looking right

tilting head left

59
Q

The most common cause of vertical diplopia that presents clinically

A

Due to CN 4 palsy

60
Q

Tectum

A

A region of the brain. Dorsal part of the midbrain (mesencephalon)

61
Q

Tegmentum

A

Region ventral to the ventricular system, responsible for auditory and visual reflexes

62
Q

The most sensitive way to observe vertical deviations

A

Have the patient look left and right

63
Q

Pathway of CN V

A

Leaves brainstem dorsally –> Circles cerebral peduncles –> passes between superior and posterior cerebral arteries –> Travels in the subarachnoid space –> enters tentorium and goes through can sinus and SOF to innervate SO

64
Q

Most reliable sign in TED

A

Upper lid retraction

65
Q

__% of graves pts have eyelid retraction

__% of pts with graves ophthalmopathy have eyelid retraction

A

50

90

66
Q

When you see someone with an eyelid retraction, what do you do? How do you know its not a ptosis of the other lid ?

A
  1. Check for contraction of frontalis muscle
  2. Push in on the patient’s frontal muscle with thumb to eliminate input from CN 7. ??????
  3. Look at pupils
  4. Raise the ptotic lid and look at what happens with the retracted one
67
Q

Grafe’s sign

A

Lid lag. Less reliable than UL retraction.

Ask pt to look up, then slowly follow your finger down for 10 seconds. When the patient looks down, the lids don’t follow the globes.

1 Neuro Eye Diseases (3 decks)

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