NV - Double Vision I - Week 4

Question 1

List 8 history questions that should be asked if a patient complains of double vision.

Answer 1

Does it disappear if you cover one eye?
Are both images the same?
Orientation?
Change with D/N viewing?
Change with gaze direction?
Onset?
Better or worse over time?
Constant or varying?

Question 2

What should be done for double vision cases?

Answer 2

Basic neurological screening examination

Question 3

What is the most common cause of double visiond?

Answer 3

Ischaemic oculomotor nerve palsies

Question 4

Is it common or uncommon for ocular media to cause double vision? What kind of double vision would you expect?

Answer 4

Uncommon
-monocular double vision

Question 5

List 6 examples of ocular media that can result in double vision.

Answer 5

High astigmatism
Incorrect Rx
Corneal disease
Iridectomy
Decentred IOLs
Cataract

Question 6

What are three vital clues that indicate monocular double vision may be present?

Answer 6

2 images are unequal
-one is clearer, the other is a ghost
2 images that are almost touching each other
Double vision persists despite covering one eye

Question 7

What is one of the most common causes of double vision involving the orbit/EOMs and how does it cause double vision? List three additional causes of double vision involving the orbit/EOMs.

Answer 7

Thyroid orbitopathy
-resitricts one of the EOMs
Orbital myositis
Mitochondrial myopathy
CPEO
-chronic progressive external ophthalmoplegia

Question 8

List a condition that can mimic double vision.

Answer 8

Myasthenia gravis

Question 9

What three nerves are often the most dangerous if involved with double vision and why?

Answer 9

CN3, 4, and 6 because they are often caused by an intracranial aneurysm or brain tumour compression

Question 10

What percentage of CN3 palsies are life-threatening?

Answer 10

Up to 33%

Question 11

If a patient has a life-threatening CN3 palsy, how long after onset of double vision may death occur?

Answer 11

They may die within hours or days of onset

Question 12

What is often the first presenting complaint in patients with an undiagnosed brain aneurysm?

Answer 12

Double vision

Question 13

Are partial CN3 palsies easy or hard to diagnose? Explain why.

Answer 13

Hard because they can present with various patterns of motility deficits

Question 14

Is the rule of pupil a good way to gauge whether a brain aneurysm is present or not?

Answer 14

No

Question 15

What three things can cause double vision originating in the brain?

Answer 15

Stroke
Tumour
Degenerative disease

Question 16

List 6 possible causes of CN3 palsies. Note the most common.

Answer 16

Compression
-aneurysm
Tumours
Raised intracranial pressure
Ischaemia (most common)
Inflammation
Trauma

Question 17

List four ischaemic causes of CN3 palsies.

Answer 17

Diabetes
Hypertension
GCA
Atherosclerosis

Question 18

List two inflammatory causes of CN3 palsies.

Answer 18

Multiple sclerosis
Infection

Question 19

What is one of the earliest ocular changes that can occur with double vision?

Answer 19

Ptosis

Question 20

What pupil change is often present with double vision?

Answer 20

Increased size

Question 21

What two causes of double vision generally result in pain? What about persistent severe pain?

Answer 21

Compressive
Ischaemic
-aneurysm more likely than ischaemic with persistent severe pain

Question 22

List three possible symptoms of the cause of double vision.

Answer 22

Ptosis
Increased pupil size
Pain

Question 23

List three signs od partial CN3 palsy.

Answer 23

Strabismus
Ptosis
Enlarged pupil

Question 24

What kind of strabismus may occur as a result of CN3 palsy (4)?

Answer 24

ExoT
HyperT
HypoT
-any possibility and combinations

Question 25

What pupil response do you expect to see with partial CN3 palsy and why?

Answer 25

Poor light and near response due to weak sphincter

Question 26

If you see aberrant regeneration in a partial CN3 palsy, what cause can you rule out?

Answer 26

Ischaemic cause

Question 27

Describe aberrant regeneration in partial CN3 palsy (3).

Answer 27

Upper lid retraction Constricted pupil Abnormal EM on adduction/elevation/depression of the eye

Question 28

Describe what may be occurring with aberrant regeneration in partial CN3 palsy (2).

Answer 28

Nerve fibres to the medial rectus grow back to the sphincter Inferior rectus fibres misrouted to the letvator

Question 29

If you see aberrant regeneration in partial CN3 palsy and there is no history of nerve palsy, what is likely happening (3) and where?

Answer 29

Likely a slow-growing lesion, an aneurysm, or meningioma compressing CN3 -often in the cavernous sinus

Question 30

What three things would you expect to see with complete CN3 palsy?

Answer 30

Full ptosis Eyes down and out Normal or enlarged pupil

Question 31

If you see a normal pupil in what you suspect is complete CN3 palsy, what cause can be ruled out?

Answer 31

Ischaemic causes

Question 32

What scans are generally done for CN3 palsies (3)?

Answer 32

Urgent MRI brain scan plus MRA or CTA

Question 33

What is the treatment for aneurysms?

Answer 33

Clipping/coiling

Question 34

What is the treatment for CN3 palsies caused by atherosclerosis? Who is the referral to?

Answer 34

GP -stop smoking -reduce cholesterol levels -monitor sugar levels -BP control

Question 35

Are prisms generally used to treat double vision in CN3 palsies? What else?

Answer 35

May help with small deviations -else patch eye for total occlusion

Question 36

What are four general causes of CN4 palies?

Answer 36

Trauma Ischaemic Compressive Inflammatory

Question 37

List four useful tests to consider for CN palsies.

Answer 37

Vertical fusion reserves Degree of extortion with double maddox rod Observe fundus extorsion -ONH/macula in the normal position FAT for head tilt to the side of the lower eye

Question 38

List two symptoms of acquired unilateral CN4 palsy.

Answer 38

Vertical or oblique ± torsional diplopia

Question 39

List 7 signs of acquired unilateral CN4 palsy.

Answer 39

Head tilt away from the side of the palsy HyperT or oblique deviation of one eye Secondary overaction of ipsilateral inferior oblique Underaction of ipsilateral superior oblique Vertical fusional reserves <5PD Double maddox rod - extorsion <10 degrees Fundus - extorsion on the affected side

Question 40

List two symptoms of acquired bilateral CN4 palsy.

Answer 40

Torsional ± vertical or oblique diplopia -opposite to unilateral acquired CN4 palsy

Question 41

List 8 signs of acquired bilateral CN4 palsy.

Answer 41

Head tilt, often downwards HyperT orno deviation HyperT reverses with gaze Overaction of both inferior obliques Underaction of both superior obliques Vertical fusional reserves <5PD Double maddox rod - often extorsion >10 degrees Fundus - extorsion on both sides

Question 42

List two symptoms of congenital unilateral CN4 palsy.

Answer 42

No torsion -images are double but not lifted Vertical or oblique DV -often intermittent

Question 43

List 5 signs of acquired unilateral CN4 palsy.

Answer 43

Head tilt away from palsy side EM same as aqcuired Vertical fusional reserves <5PD Double maddox rod - no subjective torsion Fundus - extorsion of affected side

Question 44

What may often occur with chronic head tilt due to congenital unilateral CN4 palsy?

Answer 44

Hemifacial hypoplasia

Question 45

List three differential diagnoses for congenital unilateral CN4 plasy.

Answer 45

Skew deviation Partial CN3 palsy Myasthenia gravis

Question 46

What is a must for non-traumatic bilateral CN4 palsy and to exclude what?

Answer 46

MRI brain scan to exclude pineal region tumour

Question 47

After how long can traumatic causes of CN4 palsies generally resolve?

Answer 47

6 months

Question 48

When may strabismus surgery be indicated for CN4 palsy`(2)?

Answer 48

Congenital or non-resolving CN4 palsies

Question 49

List 5 causes of CN6 palsies.

Answer 49

Compression Increased intracranial pressure Trauma Ischaemia Inflammation

Question 50

What is a symptom of CN6 palsy? What about if its only mild (2)?

Answer 50

Horizontal double vision -if mild, only present at distance or on side gaze to the side of the lesiond

Question 51

If you have a case of possible CN6 palsy, when should you suspect tumour causes (10)?

Answer 51

Gradual or intermittent onset of double vision Progression of double vision over days/weeks Pain Numbness/parasthesia New onset of facial weakness, deafness, tinnitus, or vertigo on the same side as the palsy Decreased corneal/fcial sensation Facial weakness, deafness, nystagmus Limited EM in other gazes, ptosis, anisocoria Bitemporal field defect Abduction deficit of the other eye

Question 52

What is a sign of CN6 palsy?

Answer 52

Decreased abduction of one eye with slow abducting saccades

Question 53

List three differential diagnoses for CN6 palsy.

Answer 53

Myasthenia gravis Restrictive esotropia from a tight medial rectus -TED Congenital duanes retraction syndrome -no double vision

Question 54

What should you do if there are multiple affected cranial nerves or unexplained double vision?

Answer 54

Urgent referral to a neuro-ophthalmologist