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Y. Strabismus > Paralytic/Special Strabismus — COMPLETE > Flashcards

Paralytic/Special Strabismus — COMPLETE Flashcards

1
Q

Paresis vs. Paralysis vs. Palsy

A

Paresis = partial paralysis
Paralysis = complete paralysis
Palsy — could mean either (vague term)

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2
Q

Primary Deviation refers to strab when _____ (affected/unaffected) eye is fixating

A

Unaffected

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3
Q

Secondary Deviation refers to strab when _____ (affected/unaffected) eye is fixating

A

Affected

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4
Q

Typical onset of paralytic strabismus

A

Usually sudden

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5
Q

Patients with paralytic strabismus will likely first become aware of

A

Diplopia

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6
Q

Describe how paralytic strabismus may affect other EOMs/other eye other than the affected muscle/eye

A

On initial onset of paralysis, other EOMs (on both eyes) will over-exert itself trying to assist/overcompensate for the affected muscle.

Over time, this can fatigue the other muscles, and eventually they will settle into a “new normal” without the affected muscle

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7
Q

Describe stages of Paralytic Strabismus

A

Stage 1: weakness of paralyzed muscle
Stage 2: overaction and contracture of antagonist
Stage 3: deviation spreads to all fields and becomes more comitant

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8
Q

TRUE/FALSE: all paralytic deviations undergo the 3 stages

A

FALSE; variable

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9
Q

Tests (3) to identify paralytic muscle in vertical deviations

A
  1. Bielschowsky
  2. Parks 3 Step
  3. Comitancy Tests (e.g. CT in 9 gaze)
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10
Q

What are 2 reasons why a patient may have an anomalous head turn/tilt?

A
  1. Fixate with deviated eye (as opposed to sound eye)
  2. Separate image even further to avoid diplopia
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11
Q

How do you differentiate between Congenital and Ocular Torticollis?

A
  1. Onset — congenital usually appears within 6 months of birth, whereas ocular rarely occurs before 18 months
  2. Head Position difficult/impossible to straighten when congenital; with ocular, head can passively/voluntarily be straightened
  3. In congenital, no visual disturbances, even on occlusion; in ocular, diplopia when straighten head or tilting to other side, but upon occlusion of paretic eye, head likely straightens
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12
Q

Paretic Strab:
Which age demographic most associated with etiology of trauma to Oculomotor nuclei/nerve?

A

Young adults

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13
Q

Paretic Strab:
Which age demographic most associated with etiology of vascular disorders?

A

Older patients

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14
Q

Paretic Strab:
Which age demographic most associated with etiology of MG?

A

Females < 30 years old

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15
Q

Paretic Strab:
Which age demographic most associated with etiology of MS?

A

Females, 20-50 yrs

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16
Q

Paretic Strab:
Which age demographic most associated with etiology of Tumors?

A

Infants/children

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17
Q

Paretic Strab:
Which age demographic most associated with etiology of Infections?

A

Infants/children

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18
Q

Developmental Strab:
1. Mode of onset — gradual or sudden?
2. Age of onset?

A

Mode: Usually gradual or shortly after birth
Age: Between birth and 6 yrs

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19
Q

Paretic Strab:
1. Mode of onset — gradual or sudden?
2. Age of onset?

A

Mode — sudden onset
Age — can occur at any age

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20
Q

Developmental Strab:
1. Diplopia — common or uncommon?
2. Suppression — common or uncommon?
3. Amblyopia — common or uncommon?
4. Correspondence — AC or NC?

A

Diplopia — uncommon
Suppression — common
Amblyopia — common
Correspondence — typically AC

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21
Q

Paretic Strab:
1. Diplopia — common or uncommon?
2. Suppression — common or uncommon?
3. Amblyopia — common or uncommon?
4. Correspondence — AC or NC?

A

Diplopia — common
Suppression — uncommon
Amblyopia — uncommon
Correspondence — NC

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22
Q

Developmental Strab:
1. Usually comitant or incomitant?
2. Head posture usually normal or abnormal?

A
  1. Usually comitant (unless A/V Pattern)
  2. Head posture normal
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23
Q

Paretic Strab:
1. Usually comitant or incomitant?
2. Head posture usually normal or abnormal?

A
  1. Usually incomitant (but becomes comitant over time)
  2. Head posture abnormal
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24
Q

Most prevalent ocular CN palsy (Mayo Clinic 1992)?

A

CN 6

but some studies indicate CN 4, so inconclusive

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25
Prognosis of Acquired CN 6 Palsy
Most spontaneously recovers
26
Möbius Syndrome triad + other sx/sx (5)
TRIAD: 1. Congenital bilateral abducens paralysis 2. Facial diplegia 3. Microglossia Other signs/symptoms: 1. Lack of facial musculature 2. Mental retardation 3. Congenital heart defects 4. Limb and chest deformities 5. Hearing, speech, and swallowing defects
27
Treatment for Möbius Syndrome
1. Strab surgery if ET 2. Tx exposure keratoapthy
28
What makes CN 4 so vulnerable to trauma?
Thin and long course
29
What type of injury is considered one of the main causes of CN 4 palsy?
Closed head injury from frontal blow
30
Hypertropia, associated with CN 4 palsy, is worse in which gaze — ipsilateral or contralateral?
Contralateral
31
With a CN 4 Palsy, the pt will likely prefer to tilt their head to the ____ (ipsilateral/contralateral) side
Contralateral
32
Hypertropia, associated with CN 4 palsy, is worse in which head tilt — ipsilateral or contralateral?
Ipsilateral
33
What are the four golden rules of vertical strabismus?
1. **Caused by SO**, unless proven otherwise 2. **Congenital**, unless proven otherwise 3. If not congenital, **traumatic** unless proven otherwise 4. If not congenital, decompensated, traumatic, or vascular, **must rule out neoplasm**
34
In a congenital SO palsy, what is likely to occur upon patching?
Head tilt disappears
35
Bilateral SO palsies are most commonly _____ (congenital/acquired)
Acquired, usually severe head trauma
36
Clinical features of Bilateral SO Palsy (6)
1. Chin down 2. Small vertical deviation in primary gaze 3. LHyper on R gaze and RHyper on L gaze 4. LHyper on L gaze and RHyper on R gaze 5. V-Pattern 6. Bilateral excyclotorsion
37
Which muscles are potentially affected in a cyclovertical deviation?
Either oblique or recti muscles
38
Why could a small deviation of 1-2 PD cause diplopia in vertical deviation, but not in horizontal?
Vertical Fusional vergence range much weaker than fusional convergence/divergence
39
In what ways are horizontal and vertical deviations different?
1. Neuroadaptations less common in vertical 2. Symptoms more common 3. Rarely comitant 4. Magnitude generally smaller 5. Size does not correlate with extent of pt’s issues
40
If the superior division of the 3rd nerve is affected, what ocular symptoms would you expect?
Ipsilateral hypotropia and ptosis
41
How would a pt with a bilateral CN 3 palsy likely hold their chin?
Chin down
42
What are some clinical features of CN 3 palsy? *Include the muscle associated with defect*
1. Both horizontal and vertical diplopia 2. Exotropia (MR defect) 3. Hypotropia (SR/IO defect) 4. Ptosis (Levator defect) 5. Limited depression on abduction (IR defect) 6. Dilated pupil (symp fibers — not always, though)
43
T/F: it is possible to have *Acquired* Duane’s Syndrome
TRUE, but highly, highly rare
44
Most prevalent Duanes Type
Type I
45
In Duane’s Retraction Syndrome, globe retraction and Palpebral narrowing occurs on which action?
A**d**duction *due to co-contraction of medial and lateral recti*
46
Duane Type **I** is characterized by limited or absent
A**b**duction
47
Duane Type **II** is characterized by limited or absent
A**d**duction
48
Duane Type **III** is characterized by limited or absent
A**b**duction *and* A**d**duction
49
Duane’s - Most common in: males/females - Most common in: right eye/left eye - Most commonly: unilateral/bilateral
Females, left eye, unilateral
50
T/F: many Duane’s patients are *asymptomatic*
TRUE
51
Etiology of Duane’s
CN 6 silent or missing In some cases, CN 3 anomalously innervates LR → MR and LR contract simultaneously (MR>LR) → retraction of globe, limit on adduction, + narrowing of palpebral fissure
52
Treatment for Duanes
If asymptomatic, nothing Surgery if significant strab in primary gaze, significant head position, or significant upshot or undershoot
53
Internuclear Ophthalmoplegia (INO) characterized by
A**d**duction deficit in ipsilateral eye and nystagmus in contralateral eye
54
INO caused by lesions in
MLF
55
T/F: Patients with INO are usually ortho in primary gaze
TRUE
56
If a patient is under 50 and exhibits signs of INO, the cause is likely
Demyelination or a tumor
57
If a patient is over 50 and exhibits signs of INO, the cause is likely
vascular disease, AV malformations, aneurysms, or basilar artery occlusion *could also be demyelination or tumor*
58
Pts with INO will experience diplopia in ____ (ipsilateral/contralateral) gaze
Contralateral
59
What is WEBINO?
“Wall Eyed Bilateral Internuclear Ophthalmoplegia” Refers to a bilateral INO associated with a rostral midbrain lesion, which results in bilateral XT with abducting nystagmus
60
One and a Half Syndrome is characterized by
Ipsilateral gaze palsy (one) and INO (half) *the only residual movement is abduction of contralateral eye, but exhibits abduction nystagmus*
61
One and a Half Syndrome is caused by
Damage to PPRF and MLF on the same side
62
General Fibrosis Syndrome
AD anomaly in which all EOMs + levator are fibrotic
63
Strabismus Fixus
Rare congenital fibrosis of both medial recti muscles → severe ET
64
Another name for Brown’s Syndrome
Superior Oblique Tendon Sheath Syndrome
65
Brown’s Syndrome is characterized by
Lack of elevation on adduction and (+) FDT
66
In Brown’s Syndrome, elevation on adduction is
Restricted
67
In Brown’s Syndrome, elevation on abduction is
Normal or slightly decreased
68
What alphabet pattern is primarily associated with Brown’s?
V Patterm
69
Explain why one eye “rolls up” in Brown’s
Underacting inferior oblique causes an overacting superior Rectus in the contralateral eye
70
What causes the audible “click” in Brown’s?
Globe sliding under the SO sheath
71
What causes the audible “click” in Brown’s?
Globe sliding under the SO sheath
72
Brown’s - Most common in: males/females - Most common in: right eye/left eye - Most commonly: unilateral/bilateral
Females, right eye, unilateral
73
Treatment for Brown’s
**Congenital**: no treatment if asymptomatic, but strab surgery if affected eye has significant (10-15∆ of Hypo in primary gaze) strab or pt presents with abnormal head position **Acquired**: anti-inflammatory meds + steroid injection into trochlea, surgery to remove nodule
74
4 ways to differentiate between Brown’s and IO Palsy
1. **FDT** — Browns will be (+); IO will be (-) 2. **Bielschowsky** — Browns: (-) head tilt; IO: (+) Head tilt 3. Browns — no torsion issue; IO: (+) **incyclotorsion** 4. Not likely to have **horizontal deviation** with Browns; likely in IO
75
Dissociated Vertical Deviation is characterized by
Spontaneous up-drift of either eye when not focused (e.g. fatigued, daydreaming, occluding an eye)
76
T/F: DVD occurs do to Hering’s Law
FALSE; it does not adhere to Hering’s
77
DVD is often associated with which type of strab?
Infantile ET
78
What wall(s) is/are typically affected with Orbital BlowOut Fractures?
Medial wall or floor
79
When an **adult** has an orbital blowout fracture, surgery should be considered if… (5)
1. Diplopia 2. Large floor fracture 3. Facial asymmetry 4. IR entrapment 5. Enophthalmos
80
Why does an orbital fracture differ in an adult versus a child?
Bones are pliable in a child
81
“White Eyed Blow Out Fracture”
Blowout fracture without the appearance of blood
82
How soon should a surgery taken place for a child with a blowout fracture?
ASAP (preferably within 24 hrs)
83
Oculocardiac Reflex
Traction on EOMs or compression of eyeball → Decreased pulse rate → nausea/vomiting & bradycardia
84
Myasthenia Gravis
Autoimmune disease in which antibodies bind to ACh receptors of striated muscle cause it muscle weakness
85
T/F: Mysathenia Gravis is pupil-sparing
TRUE; it does not affect the pupil or the ciliary muscle
86
Typical demo for MG
Women < 30’s
87
T/F: MG symptoms worse in the morning
FALSE; worse when pt is fatigued
88
T/F: most MG pts have ocular involvement
TRUE (90%)
89
MG signs/symptoms (5)
1. Unilateral ptosis with contralateral lid retraction 2. Diplopia 3. Dysarthria 4. Dysphagia 5. Cogan’s Lid Twitch
90
Testing for MG (4)
1. Ice test 2. Edrophonium Chloride Test 3. AntiACh receptor antibodies test 4. Thyroid function test
91
TX for MG
1. Oral anticholinesterase 2. Oral steroids 3. If applicable, remove Thymoma *+ neuro consult*
92
Graves Disease
Immune mediated disorder causing thyroid dysfunction (hyperthyroidism)
93
Risk factors for Graves
- Female - Smoker
94
Graves is the most common cause of ______ in adults
Proptosis
95
What are the 4 clinical components of ocular signs/symptoms?
1. Eyelids — retraction, reduced blinking, lagophthalmos 2. Eye surface — edema, SPK, conj injection, exophthalmos 3. Ocular Motility — limited EOM, (+) FDT 4. Optic Neuropathy — Decreased VA and color vision, (+) APD, and VF defect
96
Graves Treatment
1. Treat underlying thyrioid dysfunction 2. Tx Dry eye 3. If compressive, corticosteroids, radiation, and/or surgery
97
For visually significant congenital CAT, intervention for unilateral cases is recommended before
6 weeks
98
For visually significant congenital CAT, intervention for bilateral cases is recommended before
8 weeks

Y. Strabismus (8 decks)

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