Differential diagnosis- recent v longstanding palsies

Question 1

Recent assumes

Answer 1

aquired

Question 2

Is long standing always congenital?

Answer 2

may or may not be congenital

Question 3

Differences

Answer 3

It can be difficult to tell if longstanding or congenital- poor history in adults
Congenital may have abnormal tendencies

Question 4

Important to note

Answer 4

• determine further investigations
• awareness of preventing further investigating to relieve worry and discomfort
• be able to offer management
• consider cost on NHS and patient

Question 5

History in recent palsies

Answer 5

May report exact cause e.g. after illness
? Previous episode that has recovered
FH coincidental
Aware of AHP
Diplopia

Question 6

History in long standing palsies

Answer 6

No obvious cause
May have attended as a child
Familial cases of 4th NP
Unaware of AHP
? Facial asymmetry

Question 7

Photographs in longstanding palsies

Answer 7

Might show presence of AHP from childhood
Shows progression as they age shows that it is acquired and not congenital

Question 8

AHP in recent palsies

Answer 8

AHP resolves on occlusion of one eye or in dark

Question 9

AHP in longstanding palsies

Answer 9

AHP maintained on occlusion of one eye or in dark
measure this due to long standing

Question 10

History in recent palsies

Answer 10

Sudden onset of symptoms
Diplopia
Very troubled by symptoms
Torsion (4th NP)

Question 11

History in long standing palsies

Answer 11

Vague onset of symptoms
Diplopia absent/intermittent (when manifest)
Not so troubled by symptoms
Worse when tired

Question 12

History in both

Answer 12

Can be precise symptoms if acquired as it is new and disturbing
Bilateral 4th nerve have torsional diplopia and is also disturbing
Can be decompensating due to illness or new hobby/ job

Question 13

Cover test in recent palsies

Answer 13

Incomitant deviation (disappears quickly)
Small deviation for degree of symptoms
Marked symptoms even in small deviation when recently acquired

Question 14

Cover test in long standing palsies

Answer 14

Fairly concomitant deviation
May be controlling large phoria

Question 15

Visual acuity in recent palsies

Answer 15

Any reduction in visual acuity is coincidental
(rarely could be associated with cause -pressure on optic nerve from tumour; previous retrobulbar neuritis etc)

Question 16

Visual acuity in long standing palsies

Answer 16

Amblyopia if manifest from early age
Reduced VA could be cause for decompensation

Question 17

Ocular movements and HESS in recent palsies

Answer 17

Incomplete muscle sequelae (may only be the first 2 stages)
Incomitant on Hess chart

Question 18

Ocular movements and HESS in longstanding palsies

Answer 18

Muscle sequelae developed(may have difficulty identifying originally affected muscle)
Hess chart shows fields of similar size
- can be difficult to find primary muscle

Question 19

Angle of deviation in recent palsies- greater when fixing with which eye

Answer 19

Incomitant
Angle greater fixing with affected eye
2° > 1°

Question 20

Angle of deviation is longstanding palsies

Answer 20

Concomitant

Subjective adaptation to torsion –when measured using fundus there is discrepancy between subjective and objective measurement

Objective > subjective
difference of >18º between subjective and objective measurement indicates subjective adaptation (McNamara et al, 1995)

Question 21

Sizes in both

Answer 21

Small palsy – small deviation
Large palsy – large deviation

Don’t have to develop full muscle sequelae or primary deviation/ incomitance

Question 22

Binocular function in recent palsies

Answer 22

Normal vertical fusion range
If no constant diplopia
No suppression (unless child)
NB Fusion may be affected in head injuries
Do have BSV as they become manifest which gave them diplopia so after palsy disappears regain their BSV

Question 23

Binocular function in longstanding palsies
VFR?

Answer 23

Increased vertical fusion range
If vertical deviation
Patients may have suppression in positions of gaze where manifest

Question 24

Vertical fusion range

Answer 24

SO palsy fusion range:

> 10 may be used in support of a congenital SO palsy diagnosis(Sharma & Abdul-Rahim, 1992)
10 - 25 in congenital cases (Miller, 1985)
- study in pp

Question 25

Field of BSV in recent palsies

Answer 25

Small field for size of defect

Question 26

Field of BSV in longstanding palsies

Answer 26

Larger field for size of defect

Question 27

Past pointing in recent palsies

Answer 27

Is present

Question 28

Past pointing in longstanding

Answer 28

Is absent

Question 29

To know

Answer 29

Importance of making differential diagnosis
If in doubt…investigate further!
Remember…patients with strabismus can also develop neurogenic palsies