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
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
3
Q
Types of neurological strabismus
A
- CN palsies
- neuro diseases: MG, botulism
- posterior fossa tumors or malformations
- raised ICP
4
Q
Sypmtoms of neuro strabismus
A
Double vision Blurry vision Reduced peripheral vision Headaches Dizziness
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
6
Q
Etiology in children for CN3 palsy
A
Congenital
Vascular
Primary tumor
Metastatic tumor
7
Q
Young adults etiology of CN3 palsy
A
Demyelination
Vascular
Tumor
8
Q
Older adults etiology of CN3 palsy
A
Vascular
Tumor
9
Q
Vascular CN3 palsy
A
Diabetes
HTN
Pupil sparing
10
Q
More vascular related CN3 palsy
A
Eye down and out with pupil sparing
11
Q
Tumor or IC aneurysm CN3 palsy
A
Eye down and out with pupil dilated
12
Q
Most common vessels involved in CN3 palsy with vascular involvement
A
Posterior communicating artery
-ICA and basilar also could be a problem
13
Q
Acute CN3 palsy with vascular involvement
A
Risk of rupture, subarachnoid hemorrhage (pain_)
14
Q
Tumor CN3 palsy primary tumors
A
Neuromas and schwanomas
-tumors adjacent to the nerve: pituitary, sphenoid wing menagioma
15
Q
Trauma and CN3 palsy
A
Severe blows to head with skull fracture and or loss of consciousness
16
Q
Migraine CN3 palsy
A
Ophthalmoplegic migraine, form a recurrent demyelination neuropathy
Children and young adults
17
Q
Inflammatory CN3 palsy
A
MS
18
Q
Infectious CN3 palsy
A
Meningitis
Viral
19
Q
Test to evaluate for CN3 palsy
A
case Hx External observation VA CT EOMs Pupil testing NPC Accommodative testing Hess Lancaster test
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
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
22
Q
Longest intracranial pathway
A
Cranial nerve 4
23
Q
How does the CN4 run
A
Crosses in back of the brain stem, partially encircling the midbrain, decussates after midbrain
24
Q
Where is CN4 nucleus close to
A
Near descending sympathetic fibers
25
CN4 palsy and horners
Ipsilateral pre-ganglionic Horners sysndrome
| -triad: miosis, ptosis, anhidrosis
26
Congenital CN4 palsy
Abnormal development of CN4 nuclear OR
| Abnormal developments f peripheral nerve or tendon
27
Most common cause of acquires isolated CN4 palsy
1; idiopathic
2. Head trauma (loss of consciousness)
- micorvasculopathy
28
These CN4 palsy things can affect other cranial nerve palsies
Tumor
Aneurysm
MS
Iatrogenic injury
29
Test to evaluate for CN4 palsy
```
\case Hx
External observation
CT
EOMs
Pupil testing
Parks 3
NPC
Hess-Lancaster
```
30
What does the CN 6 innervate (abducens nerve)
Lateral rectus
31
What does the the eye do in a CN6 palsy
Eye turns in (eso)
32
Compensation of a CN6 palsy
Head turn towards affected eye
| -LRL, left head turn
33
Pathway for CN 6
Longest external course through cranium
34
What is the longest external course through cranium
CN6
35
What is CNS6 susceptible to
```
Injury
Increased ICP
Mastoid infection
Skull fracture
Tumors
```
36
Lesions of nerve root, nucleus, causes of CN6
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)
37
Most commonly affected oculomotor nerve in adults
CN6
38
Second most common affected oculomotor nerve in children
CN6
39
What is the most common affected oculomotor nerve in children
CN4
40
Etiology of CN6 palsy
```
Trauma
Aneurysm
Ischemic
Idiopathic
Demyelination
Neoplasm
Inflamamtgory
Meningitis
```
41
What nerve is most affected from trauma
CN4
42
Test to evaluate CN6 palsy
```
Case Hx
External observation
VA
CT
EOMs
Hess Lancaster
```
43
Cavernous sinus nerves that can be disrupted
CN3, 4, 5(V1 and V2), 6, or horners syndrome
44
If damage to cavernous sinus, what happens to the optic nerve
Nothing
45
Causes of cavernous sinus problems causing multiple CN to be affected
neoplasms, carotid cavernous fistula, aneurysm, fungal infection, inflammation, tolosa-hunt
46
Orbital apex syndrome
CN3, 4, 5(V1), 6, or horners syndrome
Optic nerve affected
Caused by neoplasms, fungal infection, inflammation
47
Medial rectus palsy
Exo deviation, greater at near
- Duane’s retraction syndrome
- uni/bilateral: inter nuclear ophthalmapolegia
48
Inferior rectus palsy
Hyper and exo deviation
| -MG, thyroid eye disease, blow out fracture
49
Superior rectus palsy
Bilateral, in V exo pattern
| -trauma blow out fracture, thyroid eye disease
50
Inferior oblique palsy
Eso pattern
| -browns syndrome
51
Superior rectus and inferior oblique of same eye are affected
Double elevator palsy
52
What is usually present in double elevator palsy
Bells phenomenon
| -eyes move up when eyelids are closed normally
53
Etiology of double elevator palsy
Congenital origin
| Supra nuclear defect
54
Differential diagnosis of double elevator palsy with positive forced duction test
```
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
Another name for double depressor palsy
Monocular depresssion defieicney
56
Inferior rectus and superior oblique of same eye are affected, no depression in abduction or adduction
Double depressor palsy
57
Head tilt in double depressor palsy
Tilted down (Chin depressed) to compensate for hypertrophic eye
58
Suprneuclear
Cortical control, BG, SC, thalamus, VA, cerebellum
59
Nuclear
Brain stem, ocular motor cranial nerve nuclei
60
Infranuclear
Ocular motor nerves and EOMs
61
Congenital neurogenic palsies causes
Congenital hypoplasia or absence of nucleus, CN III and VI nerve palsies
62
Traumatic causes of neurogenic causes
Head injury
63
Causes of neurogenic palsies
```
Congenital
Traumatic
Inflamamtory
Neoplasticism
Ischemic
Toxic
Demyelination disease
Idiopathic
```
64
What is a neurogenic palsy
Anything that affects the supraneuclear, nuclear, and infranuclear
65
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
Supranuclear neurogenic palsy
66
Lesion of the medial longitudinal fasciculus
Internuclear palsy
| -accompanied by ophthalmoplegia
67
What is an internuclear palsy caused by
MS in younger patients
| Vascular in elderly patients
68
Presentation of nuclear palsy
-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
What nerve is affected in and MLF palsy
Medial rectus
70
Our you see some of the CNIII muscles affected but not all,
You are thinking a nuclear problem
71
Affects CN III, IV, and VI
Infranuclear palsies
72
CN III palsy
Central, sparing pupil or peripheral with pupil convolemtn
73
If there is pupil sparing in CN III palsy
Cause if vascular
74
If the the pupil is involved in the CN III palsy
Cause is likely an aneurysm
75
New onset of diplopia
Do case history, very important to know if it is an emergency
76
How to determine the cause of the strabismus
Determine the etiology
Treat the underlying primary condition
If suspect aneurysm or neoplasm, emergency, seek immediate care
77
Aneurysm suspected in strabismus
Order an angography and MRA
78
If you suspect a neoplasm in strabismus
MRI or CT scan
79
Ischemic etiology
Older than 40
Sudden onset
HTN, diabetes, smoking
Order blood work
80
Prognosis of ischemic causing strabismus
Resolves on its own within 3 months
81
Treatment for ischemic strabismus
Systemic factors (HTN, diabetes)
82
Rxing glasses in strabismus
- Improvement of VA can result in improved control of an otherwise uncontrolled deviation
- introduced prism to correct small deviations
83
What kind of prism can be RXed for someone with strabismus
Fresnel press on prism. For short term treatment of diplopia, but can also be used long term
-place over none dominant eye
84
Occlusion in strabismus
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
What is the best prism for long term treatment
Ground in
| Fresnel is not cosmetically appealing, so only used for short term
86
Common treatment for acute paralytic strabismus due to unilateral CN6 palsy
Botulinum neurotoxin
87
Neurotoxic protein that prevents the release of NT Ach from axon endings at the NMJ, resulting in paralysis
Botulinum neurotoxin
88
Dosage of botulinum neurotoxin
1.25-5 units into a muscle (injection)
| Need repeated procedures
89
Side effects of Botox
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
Surgery for strabismus
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
Risks of surgery for strabismus
Mild discomfort following strabismus surgery
Continued strabismus
Endophthalmitis
Ocular ischemia
