Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

OP3103- BV > 10. Introduction to paralytic strabismus > Flashcards

10. Introduction to paralytic strabismus Flashcards

1
Q

What is paralytic strabismus and what does it result in?

A

Meaning: Angle of deviation changes depending on gaze or depending on which eye is fixing.
Also known as incomitant deviation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Cause of paralytic strabismus ?

A

Poor motility in 1 or both eyes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Paralytic strabismus - Congenital or acquired?

A

Both possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is RADSIN?

A

Recti ADduct, Superior INtort

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How are versions tests?

A

When both eye are open- patients are asked to look at 9 different position of gazes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Duction are bilateral movements- true or false?

A

False- ductions are bilateral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Dextro version VS Laevoversion?

A

Dexto- px asked to look right
Laeovo- px asked to look left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

If an underaction is seen on versions, before making a diagnosis what is important?

A

It is important to check ductions as well before making a diagnosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

3 classification of limited eye movement?

A
  1. Neurogenic- majority of the palsies.
  2. Mechanical
  3. Myogenic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are neurogenic palsies?
What causes this?

A

Ductions greater than versions.
When underacting doesn’t move when both eyes are open. But when normal eye is covered, the underacting eye will get extra innervation and move.
Cause: Causes by lesions between nucleus and muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are neurogenic intranuclears?

A

VI (abducens), UV (trochlear), III (Occulomotor)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are mechanical palsies?

A

These are palsies that prevent free movement of the globe or interfere with muscle contraction and relaxation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Examples of mechanical palsies?

A

Brown’s. Duanes. TES. Blow- out facture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are myogenic palsies?

A

Palsies within the actual muscle that cause the problem. May involve individual extraocular muscles or a combination.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Examples of myogenic palsies?

A

Myasthenia Gravis, Myositis, TED (wet phase)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 4 diagnose aims when investigating paralytic palsies?

A
  1. Identify if- neuro, mechanical or myogenic
  2. What muscles are affected?
  3. Congenital vs acquired?
  4. Possible causes?
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Other than the 4 diagnose aims what other investigating paralytic palsies is needed- 4?

A
  1. Decide if referral is needed and how urgent.
  2. Treat symptoms if possible
  3. Document progress/ recovery
  4. Is it congenital or acquired? - congenital is a more worrying sign
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

AHP- Congenial vs acquired?

A

Congenial

19
Q

Congenial vs acquired- in relation to H&S?

A

Congenital= vague onset of symptoms.
Acquired = know exact time, date of when symptoms started

20
Q

Important questions to ask when patients report diplopia?

A

Vertical/ horizontal?
Monocular/ binocular?

21
Q

Is amblyopia reported in congenital issues?

A

If uncontrolled, yes

22
Q

Versions or ductions used to differential between neuro/ mechanical?

A

Versions

23
Q

Do congenital issues have potential for binocular function?

A

No

24
Q

What extra tests are done in HES as orthoptic assessments?

A

Hess, Fields of BSV
Medical - blood tests, BP, CT scan, MRI scan

25
Q

What is the referral process for palsies?

A
  1. All acquired nerve palsies/ motility problems need referral to eye causality.
    (Young patients may require a more urgent referral compared to adults - >55 and children- to investigate for aneurysms, tumor, raised ICP).
  2. <55 - often cause is microvascular in origin and therefore referred to eye causality, not life threating. If they have other symptoms i.e. related to stroke- emergency to A&E.
  3. Known congenital issue in a patient, not symptomatic = no referal.
  4. Suspected congenital issue, diagnosis not confirmed yet = refer for investigation.
26
Q

3 types of neurogenic palsies?

A
  1. 6th nerve palsy
  2. 4th nerve palsy
  3. 3rd nerve palsy
27
Q

What is seen on 6th nerve palsy?

A

the 6th nerve supplies lateral rectus. hence, limited abduction when affected.

28
Q

What is seen in bilateral 6th nerve palsy?
Cause of bilateral 6th nerve palsy?

A

Both the eyes do not move out when affected side is looking out
Cause: trauma

29
Q

4th nerve supplies?

A

Superior Oblique

30
Q

What is seen in 4th nerve palsy?

A

Hypertropic + esotropic in primary position
(Not enough pull down)

31
Q

Role of 3rd nerve?

A

It supplies medial rectus, superior rectus, inferior oblique muscle. Also innervates muscles of lid and sphincter muscle of the pupil.

32
Q

What is observed in 3rd nerve palsy?

A

Droopy lids, when eye are open = hypotropic + exotropic (down & out)

33
Q

2 causes of congenital nerve palsies?

A
  1. Isolated- nerve palsy is the only problem.
  2. Associated with other conditions- hydrocephalus, cerebral palsy, intoxications from mother, brain tumour (rare).
34
Q

What causes an isolated nerve palsy?

A

Lesion to all aspects of the nerve pathway.
Either of the nucleus or nerve.

35
Q

Most common congenital nerve palsy is?

A

4th nerve

36
Q

Difference in how congenital vs acquired palsies look, symptoms?

A

Congenital: Unacceptable cosmesis, vague onset of when diplopia started or no symptoms. No aware of long standing head posture.
Acquired: Sudden onset of diplopia, aware of uncomfortable AHP.

37
Q

How is ocular motility different in congenital vs acquired palsy?

A

Congenital: full muscle sequelae evident.
Acquired: muscle sequelae not fully developed.

38
Q

How is the vertical fusion in congenital 4 nerve palsy?

A

Extended vertical fusion, large than expected vertical phoria.

39
Q

How can you find out if AHP is long standing?

A

Ask patient to look at old pictures and see if they have always had an AHP.

40
Q

How is cover test different in neurogenic vs mechanical palsy?

A

Neurogenic = deviation in primary position reflects extents of palsy. Greater limitation in primary position.
Congenital = often only small deviation in primary position even with a large mechanical limitation of movement.

41
Q

How is ocular motility different in neurogenic vs mechanical palsy?

A

Neurogenic: motility is better on ductions than version.
Mechanical: Ductions= versions

42
Q

How is Hess in neuro vs mechanical palsy different?

A

Mechanical:Neurogenic: Space between inner and outer fields is equal. Fields displaced close to the inner field in position greatest limitation.

43
Q

Forced duction test in neurogenic vs mechanical palsy?

A

Neurogenic: full passive limitation
Mechanical: Limited passive movement

44
Q

How is IOP in mechanical vs neurogenic palsies?

A

Neurogenic- same in all positions
Mechanical- increases when looking away from position of limitation.

OP3103- BV (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions