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X. Strabismus > Paralytic Strabismus — COMPLETE > Flashcards

Paralytic 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
Q

Prognosis of Acquired CN 6 Palsy

A

Most spontaneously recovers

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26
Q

Möbius Syndrome triad + other sx/sx (5)

A

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

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27
Q

Treatment for Möbius Syndrome

A
  1. Strab surgery if ET
  2. Tx exposure keratoapthy
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28
Q

What makes CN 4 so vulnerable to trauma?

A

Thin and long course

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29
Q

What type of injury is considered one of the main causes of CN 4 palsy?

A

Closed head injury from frontal blow

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30
Q

Hypertropia, associated with CN 4 palsy, is worse in which gaze — ipsilateral or contralateral?

A

Contralateral

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31
Q

With a CN 4 Palsy, the pt will likely prefer to tilt their head to the ____ (ipsilateral/contralateral) side

A

Contralateral

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32
Q

Hypertropia, associated with CN 4 palsy, is worse in which head tilt — ipsilateral or contralateral?

A

Ipsilateral

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33
Q

What are the four golden rules of vertical strabismus?

A
  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
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34
Q

In a congenital SO palsy, what is likely to occur upon patching?

A

Head tilt disappears

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35
Q

Bilateral SO palsies are most commonly _____ (congenital/acquired)

A

Acquired, usually severe head trauma

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36
Q

Clinical features of Bilateral SO Palsy (6)

A
  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
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37
Q

Which muscles are potentially affected in a cyclovertical deviation?

A

Either oblique or recti muscles

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38
Q

Why could a small deviation of 1-2 PD cause diplopia in vertical deviation, but not in horizontal?

A

Vertical Fusional vergence range much weaker than fusional convergence/divergence

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39
Q

In what ways are horizontal and vertical deviations different?

A
  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
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40
Q

If the superior division of the 3rd nerve is affected, what ocular symptoms would you expect?

A

Ipsilateral hypotropia and ptosis

41
Q

How would a pt with a bilateral CN 3 palsy likely hold their chin?

A

Chin down

42
Q

What are some clinical features of CN 3 palsy?
Include the muscle associated with defect

A
  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
Q

T/F: it is possible to have Acquired Duane’s Syndrome

A

TRUE, but highly, highly rare

44
Q

Most prevalent Duanes Type

A

Type I

45
Q

In Duane’s Retraction Syndrome, globe retraction and Palpebral narrowing occurs on which action?

A

Adduction

due to co-contraction of medial and lateral recti

46
Q

Duane Type I is characterized by limited or absent

A

Abduction

47
Q

Duane Type II is characterized by limited or absent

A

Adduction

48
Q

Duane Type II is characterized by limited or absent

A

Abduction and Adduction

49
Q

Duane’s
- Most common in: males/females
- Most common in: right eye/left eye
- Most commonly: unilateral/bilateral

A

Females, left eye, unilateral

50
Q

T/F: many Duane’s patients are asymptomatic

A

TRUE

51
Q

Etiology of Duane’s

A

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
Q

Treatment for Duanes

A

If asymptomatic, nothing

Surgery if significant strab in primary gaze, significant head position, or significant upshot or undershoot

53
Q

Internuclear Ophthalmoplegia (INO) characterized by

A

Adduction deficit in ipsilateral eye and nystagmus in contralateral eye

54
Q

INO caused by lesions in

A

MLF

55
Q

T/F: Patients with INO are usually ortho in primary gaze

A

TRUE

56
Q

If a patient is under 50 and exhibits signs of INO, the cause is likely

A

Demyelination or a tumor

57
Q

If a patient is over 50 and exhibits signs of INO, the cause is likely

A

vascular disease, AV malformations, aneurysms, or basilar artery occlusion

could also be demyelination or tumor

58
Q

Pts with INO will experience diplopia in ____ (ipsilateral/contralateral) gaze

A

Contralateral

59
Q

What is WEBINO?

A

“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
Q

One and a Half Syndrome is characterized by

A

Ipsilateral gaze palsy (one) and INO (half)

the only residual movement is abduction of contralateral eye, but exhibits abduction nystagmus

61
Q

One and a Half Syndrome is caused by

A

Damage to PPRF and MLF on the same side

62
Q

General Fibrosis Syndrome

A

AD anomaly in which all EOMs + levator are fibrotic

63
Q

Strabismus Fixus

A

Rare congenital fibrosis of both medial recti muscles → severe ET

64
Q

Another name for Brown’s Syndrome

A

Superior Oblique Tendon Sheath Syndrome

65
Q

Brown’s Syndrome is characterized by

A

Lack of elevation on adduction and (+) FDT

66
Q

In Brown’s Syndrome, elevation on adduction is

A

Restricted

67
Q

In Brown’s Syndrome, elevation on abduction is

A

Normal or slightly decreased

68
Q

What alphabet pattern is primarily associated with Brown’s?

A

V Patterm

69
Q

Explain why one eye “rolls up” in Brown’s

A

Underacting inferior oblique causes an overacting superior Rectus in the contralateral eye

70
Q

What causes the audible “click” in Brown’s?

A

Globe sliding under the SO sheath

71
Q

What causes the audible “click” in Brown’s?

A

Globe sliding under the SO sheath

72
Q

Brown’s
- Most common in: males/females
- Most common in: right eye/left eye
- Most commonly: unilateral/bilateral

A

Females, right eye, unilateral

73
Q

Treatment for Brown’s

A

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
Q

4 ways to differentiate between Brown’s and IO Palsy

A
  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
Q

Dissociated Vertical Deviation is characterized by

A

Spontaneous up-drift of either eye when not focused (e.g. fatigued, daydreaming, occluding an eye)

76
Q

T/F: DVD occurs do to Hering’s Law

A

FALSE; it does not adhere to Hering’s

77
Q

DVD is often associated with which type of strab?

A

Infantile ET

78
Q

What wall(s) is/are typically affected with Orbital BlowOut Fractures?

A

Medial wall or floor

79
Q

When an adult has an orbital blowout fracture, surgery should be considered if… (5)

A
  1. Diplopia
  2. Large floor fracture
  3. Facial asymmetry
  4. IR entrapment
  5. Enophthalmos
80
Q

Why does an orbital fracture differ in an adult versus a child?

A

Bones are pliable in a child

81
Q

“White Eyed Blow Out Fracture”

A

Blowout fracture without the appearance of blood

82
Q

How soon should a surgery taken place for a child with a blowout fracture?

A

ASAP (preferably within 24 hrs)

83
Q

Oculocardiac Reflex

A

Traction on EOMs or compression of eyeball → Decreased pulse rate → nausea/vomiting & bradycardia

84
Q

Myasthenia Gravis

A

Autoimmune disease in which antibodies bind to ACh receptors of striated muscle cause it muscle weakness

85
Q

T/F: Mysathenia Gravis is pupil-sparing

A

TRUE; it does not affect the pupil or the ciliary muscle

86
Q

Typical demo for MG

A

Women < 30’s

87
Q

T/F: MG symptoms worse in the morning

A

FALSE; worse when pt is fatigued

88
Q

T/F: most MG pts have ocular involvement

A

TRUE (90%)

89
Q

MG signs/symptoms (5)

A
  1. Unilateral ptosis with contralateral lid retraction
  2. Diplopia
  3. Dysarthria
  4. Dysphagia
  5. Cogan’s Lid Twitch
90
Q

Testing for MG (4)

A
  1. Ice test
  2. Edrophonium Chloride Test
  3. AntiACh receptor antibodies test
  4. Thyroid function test
91
Q

TX for MG

A
  1. Oral anticholinesterase
  2. Oral steroids
  3. If applicable, remove Thymoma

+ neuro consult

92
Q

Graves Disease

A

Immune mediated disorder causing thyroid dysfunction (hyperthyroidism)

93
Q

Risk factors for Graves

A
  • Female
  • Smoker
94
Q

Graves is the most common cause of ______ in adults

A

Proptosis

95
Q

What are the 4 clinical components of ocular signs/symptoms?

A
  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
Q

Graves Treatment

A
  1. Treat underlying thyrioid dysfunction
  2. Tx Dry eye
  3. If compressive, corticosteroids, radiation, and/or surgery
97
Q

For visually significant congenital CAT, intervention for unilateral cases is recommended before

A

6 weeks

98
Q

For visually significant congenital CAT, intervention for bilateral cases is recommended before

A

8 weeks

X. Strabismus (6 decks)

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