Differential Diagnosis of Recent & Longstanding Palsies Flashcards

1
Q

What can’t we differentiate between longstanding, congenital and acquired?

A

Cannot differentiate between congenital and longstanding acquired

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2
Q

What can we use to differentiate between congenital/longstanding/acquired?

A
  • Case History
  • Questioning around symptoms
  • Old photographs
  • Look at prescription - focimeter them
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3
Q

What are the red flags we think about during case history for something being acquired?

A
  • Report exact cause
  • Recent head trauma
  • Aware of AHP
  • Coincidental family history
  • Possible previous episode that has recovered
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4
Q

What are the red flags we think about during case history for something being longstanding?

A
  • No obvious cause
  • Head trauma from past
  • Unaware of AHP
  • Familial cases of CNIV palsy
  • Attended as a child
  • Possible facial asymmetry
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5
Q

What are the symptoms that bring up a red flag for something being acquired?

A
  • Sudden onset
  • Diplopia
  • Troubled by symptoms
  • Torsion CNIV palsy
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6
Q

What are the symptoms that bring up a red flag for something being acquired?

A
  • Vague onset
  • Diplopia absent/intermittent
  • Not troubled by symptoms
  • Symptoms worse when tired (can be related to ability to control)
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7
Q

What can we observe that brings up red flags for a palsy being acquired?

A
  • Aware of new AHP
  • AHP resolves when occluding one eye or in the dark
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8
Q

What can we observe that brings up red flags for a palsy being acquired?

A
  • May have AHP from childhood (photos)
  • AHP maintained on occlusion of one eye or in the dark
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9
Q

What are we more likely to see on CT in an acquired palsy?

A
  • Incomitant deviation
  • Small deviation for degree of symptoms
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10
Q

What are we more likely to see on CT in a longstanding palsy?

A
  • Fairly concomitant deviation
  • May be controlling large phoria
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11
Q

What are we more likely to see during VA in an acquired palsy?

A
  • Any reduction in VA is generally coincidental
  • Rare has an associated cause except pressure on optic nerve from a tumour or previous retrobulbar neuritis etc.
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12
Q

What are we more likely to see during VA in a longstanding palsy?

A
  • Amblyopia if manifest from an early age
  • Reduced VA could be cause for decompensation (can be common in cataract development)
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13
Q

What are we more likely to see on OM in an acquired palsy?

A
  • Incomplete muscle sequelae (CNIII is an exception)
  • Incomitant on Hess Chart
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14
Q

What are we more likely to see on OM in a longstanding palsy?

A
  • Muscle sequelae developed (may have difficulty identifying originally affected muscle)
  • Hess chart shows fields of similar size
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15
Q

What are we likely to find during binocular functions in acquired palsies?

A
  • Normal vertical fusion range (if no constant diplopia)
  • No suppression (unless childhood strabismus or elderly and ignoring the diplopic image)
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16
Q

What are we likely to find during binocular functions in longstanding palsies?

A
  • Increased vertical fusion range (if vertical deviation)
  • Patients may have suppression (in positions of gaze where manifest)

BUT fusion may be affected in head injuries

17
Q

What did Rutstein and Corliss (1995) find out about vertical prism fusion range?

A

That extended vertical fusion ranges may not be present in CNIV palsy until over the age of 15 years! But small sample sizes.

18
Q

What vertical prism fusion range can we use to support a congenital SO palsy?

A

> 10PD (Sharma & Abdul-Rahim, 1992)

10PD - 25PD (Miller, 1985)

19
Q

What is the field of BSV likely to look like in an acquired nerve palsy?

A

Small field for size of defect

20
Q

What is the field if BSV likely to look like in a longstanding nerve palsy?

A

Larger field for size of defect

21
Q

What is the angle of deviation likely to look like in an acquired nerve palsy?

A

Angle greater fixing with affected eye

Secondary > Primary

22
Q

What is the angle of deviation likely to look like in a longstanding nerve palsy?

A

Concomitant

Secondary = Primary

23
Q

What is objective torsion?

A

Fundus photography or indirect ophthalmoscopy

24
Q

What does an intorted eye look like on fundus photography?

A

Fovea above upper line

25
Q

What does an extorted eye look like on fundus photography?

A

Fovea below lower line

26
Q

What is the normal position of the fovea in fundus photography?

A

Lies level with the lower 1/3rd of the optic disc

27
Q

If a deviation is longstanding what do we except with subjective torsion?

A

If a deviation is longstanding subjective adaptation to torsion may occur and so objective > subjective

28
Q

What is ‘subjective adaptation’?

A

When there is a difference of >18º between subjective and objective measurement indicates subjective adaptation (McNamara et al, 1995)