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Motility Block 11 > Paralytic Strabismus > Flashcards

Paralytic Strabismus Flashcards

1
Q

A vision condition in which a person can not align both eyes simultaneously under normal conditions, can be one or both eyes, an eye turn can be constant or intermittent

A

Strabismus

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2
Q

What do you need to look at to tell if its adult or child strabismus

A 
Congenital
Accommodative eET 
Abnormal visual development 
Neurological 
-onset
-head trauma
-perinatal Hx
-other neuro signs
-Old photo
-hear tilt
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3
Q

Types of neurological strabismus

A
  • CN palsies
  • neuro diseases: MG, botulism
  • posterior fossa tumors or malformations
  • raised ICP
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4
Q

Sypmtoms of neuro strabismus

A 
Double vision
Blurry vision
Reduced peripheral vision 
Headaches 
Dizziness
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5
Q

CN3 innervates

A

SR
MR
IR
IO
Superior palpebral lavatory muscle (Ptosis)
Edinger Westphal nucleus (dilated pupil, no accommodative response if problem)
-eye down and out if problem

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6
Q

Etiology in children for CN3 palsy

A

Congenital
Vascular
Primary tumor
Metastatic tumor

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7
Q

Young adults etiology of CN3 palsy

A

Demyelination
Vascular
Tumor

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8
Q

Older adults etiology of CN3 palsy

A

Vascular

Tumor

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9
Q

Vascular CN3 palsy

A

Diabetes
HTN
Pupil sparing

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10
Q

More vascular related CN3 palsy

A

Eye down and out with pupil sparing

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11
Q

Tumor or IC aneurysm CN3 palsy

A

Eye down and out with pupil dilated

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12
Q

Most common vessels involved in CN3 palsy with vascular involvement

A

Posterior communicating artery

-ICA and basilar also could be a problem

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13
Q

Acute CN3 palsy with vascular involvement

A

Risk of rupture, subarachnoid hemorrhage (pain_)

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14
Q

Tumor CN3 palsy primary tumors

A

Neuromas and schwanomas

-tumors adjacent to the nerve: pituitary, sphenoid wing menagioma

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15
Q

Trauma and CN3 palsy

A

Severe blows to head with skull fracture and or loss of consciousness

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16
Q

Migraine CN3 palsy

A

Ophthalmoplegic migraine, form a recurrent demyelination neuropathy
Children and young adults

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17
Q

Inflammatory CN3 palsy

A

MS

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18
Q

Infectious CN3 palsy

A

Meningitis

Viral

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19
Q

Test to evaluate for CN3 palsy

A 
case Hx 
External observation 
VA
CT
EOMs
Pupil testing 
NPC
Accommodative testing 
Hess Lancaster test
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20
Q

CN4 palsies innervation

A

Superior oblique

  • eye is up and in
  • right head tilt for a left SO palsy (opposite side of palsy
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21
Q

How does a patient tilt their head in a CN4 palsy

A

In the opposite direction of the palsy

Right head tilt= left superior oblique palsy

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22
Q

Longest intracranial pathway

A

Cranial nerve 4

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23
Q

How does the CN4 run

A

Crosses in back of the brain stem, partially encircling the midbrain, decussates after midbrain

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24
Q

Where is CN4 nucleus close to

A

Near descending sympathetic fibers

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25
Q

CN4 palsy and horners

A

Ipsilateral pre-ganglionic Horners sysndrome

-triad: miosis, ptosis, anhidrosis

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26
Q

Congenital CN4 palsy

A

Abnormal development of CN4 nuclear OR

Abnormal developments f peripheral nerve or tendon

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27
Q

Most common cause of acquires isolated CN4 palsy

A

1; idiopathic

  1. Head trauma (loss of consciousness)
    - micorvasculopathy
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28
Q

These CN4 palsy things can affect other cranial nerve palsies

A

Tumor
Aneurysm
MS
Iatrogenic injury

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29
Q

Test to evaluate for CN4 palsy

A 
\case Hx 
External observation 
CT
EOMs 
Pupil testing 
Parks 3 
NPC
Hess-Lancaster
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30
Q

What does the CN 6 innervate (abducens nerve)

A

Lateral rectus

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31
Q

What does the the eye do in a CN6 palsy

A

Eye turns in (eso)

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32
Q

Compensation of a CN6 palsy

A

Head turn towards affected eye

-LRL, left head turn

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33
Q

Pathway for CN 6

A

Longest external course through cranium

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34
Q

What is the longest external course through cranium

A

CN6

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35
Q

What is CNS6 susceptible to

A 
Injury 
Increased ICP 
Mastoid infection
Skull fracture 
Tumors
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36
Q

Lesions of nerve root, nucleus, causes of CN6

A

Ipsilateral paresis of lateral rectus
Convergent strabismus increasing in temporal gaze
Lateral diplopia
-ipsilateral paresis or paralysis of facial muscles for neuclues lesions (CN7 root encircles CN 6 nucleus)

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37
Q

Most commonly affected oculomotor nerve in adults

A

CN6

38
Q

Second most common affected oculomotor nerve in children

A

CN6

39
Q

What is the most common affected oculomotor nerve in children

A

CN4

40
Q

Etiology of CN6 palsy

A 
Trauma 
Aneurysm 
Ischemic 
Idiopathic 
Demyelination 
Neoplasm 
Inflamamtgory 
Meningitis
41
Q

What nerve is most affected from trauma

A

CN4

42
Q

Test to evaluate CN6 palsy

A 
Case Hx 
External observation 
VA
CT 
EOMs 
Hess Lancaster
43
Q

Cavernous sinus nerves that can be disrupted

A

CN3, 4, 5(V1 and V2), 6, or horners syndrome

44
Q

If damage to cavernous sinus, what happens to the optic nerve

A

Nothing

45
Q

Causes of cavernous sinus problems causing multiple CN to be affected

A

neoplasms, carotid cavernous fistula, aneurysm, fungal infection, inflammation, tolosa-hunt

46
Q

Orbital apex syndrome

A

CN3, 4, 5(V1), 6, or horners syndrome
Optic nerve affected
Caused by neoplasms, fungal infection, inflammation

47
Q

Medial rectus palsy

A

Exo deviation, greater at near

  • Duane’s retraction syndrome
  • uni/bilateral: inter nuclear ophthalmapolegia
48
Q

Inferior rectus palsy

A

Hyper and exo deviation

-MG, thyroid eye disease, blow out fracture

49
Q

Superior rectus palsy

A

Bilateral, in V exo pattern

-trauma blow out fracture, thyroid eye disease

50
Q

Inferior oblique palsy

A

Eso pattern

-browns syndrome

51
Q

Superior rectus and inferior oblique of same eye are affected

A

Double elevator palsy

52
Q

What is usually present in double elevator palsy

A

Bells phenomenon

-eyes move up when eyelids are closed normally

53
Q

Etiology of double elevator palsy

A

Congenital origin

Supra nuclear defect

54
Q

Differential diagnosis of double elevator palsy with positive forced duction test

A 
Blowout fracture 
Thyroid eye disease 
Browns sysndrome 
Congenital fibrosis of the inferior rectus muscle 
General fibrosis syndrome

-resitant to move, so it cant be double elevator palsy

55
Q

Another name for double depressor palsy

A

Monocular depresssion defieicney

56
Q

Inferior rectus and superior oblique of same eye are affected, no depression in abduction or adduction

A

Double depressor palsy

57
Q

Head tilt in double depressor palsy

A

Tilted down (Chin depressed) to compensate for hypertrophic eye

58
Q

Suprneuclear

A

Cortical control, BG, SC, thalamus, VA, cerebellum

59
Q

Nuclear

A

Brain stem, ocular motor cranial nerve nuclei

60
Q

Infranuclear

A

Ocular motor nerves and EOMs

61
Q

Congenital neurogenic palsies causes

A

Congenital hypoplasia or absence of nucleus, CN III and VI nerve palsies

62
Q

Traumatic causes of neurogenic causes

A

Head injury

63
Q

Causes of neurogenic palsies

A 
Congenital 
Traumatic 
Inflamamtory 
Neoplasticism 
Ischemic 
Toxic 
Demyelination disease 
Idiopathic
64
Q

What is a neurogenic palsy

A

Anything that affects the supraneuclear, nuclear, and infranuclear

65
Q

Lesions above the level of ocular motor nerve nuclei that presents with gaze palsies, tonic gaze deviation, saccadic and smooth pursuit disorders, vergences abnormalities, nystagmus, ocular oscillations

A

Supranuclear neurogenic palsy

66
Q

Lesion of the medial longitudinal fasciculus

A

Internuclear palsy

-accompanied by ophthalmoplegia

67
Q

What is an internuclear palsy caused by

A

MS in younger patients

Vascular in elderly patients

68
Q

Presentation of nuclear palsy

A

-unilateral CN III with bilateral ptosis
-unilateral CN III with contralteral superior rectus underaction
-isolated EOM palsy of inferior rectus, inferiror oblique, or medial rectus
-Browns sysndrome
Bilateral CN III with spared elevator function

69
Q

What nerve is affected in and MLF palsy

A

Medial rectus

70
Q

Our you see some of the CNIII muscles affected but not all,

A

You are thinking a nuclear problem

71
Q

Affects CN III, IV, and VI

A

Infranuclear palsies

72
Q

CN III palsy

A

Central, sparing pupil or peripheral with pupil convolemtn

73
Q

If there is pupil sparing in CN III palsy

A

Cause if vascular

74
Q

If the the pupil is involved in the CN III palsy

A

Cause is likely an aneurysm

75
Q

New onset of diplopia

A

Do case history, very important to know if it is an emergency

76
Q

How to determine the cause of the strabismus

A

Determine the etiology
Treat the underlying primary condition
If suspect aneurysm or neoplasm, emergency, seek immediate care

77
Q

Aneurysm suspected in strabismus

A

Order an angography and MRA

78
Q

If you suspect a neoplasm in strabismus

A

MRI or CT scan

79
Q

Ischemic etiology

A

Older than 40
Sudden onset
HTN, diabetes, smoking
Order blood work

80
Q

Prognosis of ischemic causing strabismus

A

Resolves on its own within 3 months

81
Q

Treatment for ischemic strabismus

A

Systemic factors (HTN, diabetes)

82
Q

Rxing glasses in strabismus

A
  • Improvement of VA can result in improved control of an otherwise uncontrolled deviation
  • introduced prism to correct small deviations
83
Q

What kind of prism can be RXed for someone with strabismus

A

Fresnel press on prism. For short term treatment of diplopia, but can also be used long term
-place over none dominant eye

84
Q

Occlusion in strabismus

A

Monocular occlusion as a short term treatment for diplopia

  • good option if expect temporary condition that will resolve or prior to surgical correction
  • ful time occlusion is poorly tolerated by patients
  • not a god long term treatment, unless part-time occlusion during tasks that create diplopia (ex reading)
85
Q

What is the best prism for long term treatment

A

Ground in

Fresnel is not cosmetically appealing, so only used for short term

86
Q

Common treatment for acute paralytic strabismus due to unilateral CN6 palsy

A

Botulinum neurotoxin

87
Q

Neurotoxic protein that prevents the release of NT Ach from axon endings at the NMJ, resulting in paralysis

A

Botulinum neurotoxin

88
Q

Dosage of botulinum neurotoxin

A

1.25-5 units into a muscle (injection)

Need repeated procedures

89
Q

Side effects of Botox

A

Soreness at injection site
Weakness int he muscles that were injected
Muscle soreness that affects whole body
Difficult swallowing
A red rash that lasts several days after the injections

90
Q

Surgery for strabismus

A

Eye muscle surgery for long term treatment
May also need glasses after surgery
Meant to weaken, strengthen, or change the vector of force for a given muscle, based on the strabismus

91
Q

Risks of surgery for strabismus

A

Mild discomfort following strabismus surgery
Continued strabismus
Endophthalmitis
Ocular ischemia

Motility Block 11 (4 decks)

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