NV - Double Vision I - Week 4 Flashcards
List 8 history questions that should be asked if a patient complains of double vision.
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?
What should be done for double vision cases?
Basic neurological screening examination
What is the most common cause of double visiond?
Ischaemic oculomotor nerve palsies
Is it common or uncommon for ocular media to cause double vision? What kind of double vision would you expect?
Uncommon
-monocular double vision
List 6 examples of ocular media that can result in double vision.
High astigmatism
Incorrect Rx
Corneal disease
Iridectomy
Decentred IOLs
Cataract
What are three vital clues that indicate monocular double vision may be present?
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
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.
Thyroid orbitopathy
-resitricts one of the EOMs
Orbital myositis
Mitochondrial myopathy
CPEO
-chronic progressive external ophthalmoplegia
List a condition that can mimic double vision.
Myasthenia gravis
What three nerves are often the most dangerous if involved with double vision and why?
CN3, 4, and 6 because they are often caused by an intracranial aneurysm or brain tumour compression
What percentage of CN3 palsies are life-threatening?
Up to 33%
If a patient has a life-threatening CN3 palsy, how long after onset of double vision may death occur?
They may die within hours or days of onset
What is often the first presenting complaint in patients with an undiagnosed brain aneurysm?
Double vision
Are partial CN3 palsies easy or hard to diagnose? Explain why.
Hard because they can present with various patterns of motility deficits
Is the rule of pupil a good way to gauge whether a brain aneurysm is present or not?
No
What three things can cause double vision originating in the brain?
Stroke
Tumour
Degenerative disease
List 6 possible causes of CN3 palsies. Note the most common.
Compression
-aneurysm
Tumours
Raised intracranial pressure
Ischaemia (most common)
Inflammation
Trauma
List four ischaemic causes of CN3 palsies.
Diabetes
Hypertension
GCA
Atherosclerosis
List two inflammatory causes of CN3 palsies.
Multiple sclerosis
Infection
What is one of the earliest ocular changes that can occur with double vision?
Ptosis
What pupil change is often present with double vision?
Increased size
What two causes of double vision generally result in pain? What about persistent severe pain?
Compressive
Ischaemic
-aneurysm more likely than ischaemic with persistent severe pain
List three possible symptoms of the cause of double vision.
Ptosis
Increased pupil size
Pain
List three signs od partial CN3 palsy.
Strabismus
Ptosis
Enlarged pupil
What kind of strabismus may occur as a result of CN3 palsy (4)?
ExoT
HyperT
HypoT
-any possibility and combinations
What pupil response do you expect to see with partial CN3 palsy and why?
Poor light and near response due to weak sphincter
If you see aberrant regeneration in a partial CN3 palsy, what cause can you rule out?
Ischaemic cause
Describe aberrant regeneration in partial CN3 palsy (3).
Upper lid retraction
Constricted pupil
Abnormal EM on adduction/elevation/depression of the eye
Describe what may be occurring with aberrant regeneration in partial CN3 palsy (2).
Nerve fibres to the medial rectus grow back to the sphincter
Inferior rectus fibres misrouted to the letvator
If you see aberrant regeneration in partial CN3 palsy and there is no history of nerve palsy, what is likely happening (3) and where?
Likely a slow-growing lesion, an aneurysm, or meningioma compressing CN3
-often in the cavernous sinus
What three things would you expect to see with complete CN3 palsy?
Full ptosis
Eyes down and out
Normal or enlarged pupil
If you see a normal pupil in what you suspect is complete CN3 palsy, what cause can be ruled out?
Ischaemic causes
What scans are generally done for CN3 palsies (3)?
Urgent MRI brain scan plus MRA or CTA
What is the treatment for aneurysms?
Clipping/coiling
What is the treatment for CN3 palsies caused by atherosclerosis? Who is the referral to?
GP
-stop smoking
-reduce cholesterol levels
-monitor sugar levels
-BP control
Are prisms generally used to treat double vision in CN3 palsies? What else?
May help with small deviations
-else patch eye for total occlusion
What are four general causes of CN4 palies?
Trauma
Ischaemic
Compressive
Inflammatory
List four useful tests to consider for CN palsies.
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
List two symptoms of acquired unilateral CN4 palsy.
Vertical or oblique ± torsional diplopia
List 7 signs of acquired unilateral CN4 palsy.
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
List two symptoms of acquired bilateral CN4 palsy.
Torsional ± vertical or oblique diplopia
-opposite to unilateral acquired CN4 palsy
List 8 signs of acquired bilateral CN4 palsy.
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
List two symptoms of congenital unilateral CN4 palsy.
No torsion
-images are double but not lifted
Vertical or oblique DV
-often intermittent
List 5 signs of acquired unilateral CN4 palsy.
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
What may often occur with chronic head tilt due to congenital unilateral CN4 palsy?
Hemifacial hypoplasia
List three differential diagnoses for congenital unilateral CN4 plasy.
Skew deviation
Partial CN3 palsy
Myasthenia gravis
What is a must for non-traumatic bilateral CN4 palsy and to exclude what?
MRI brain scan to exclude pineal region tumour
After how long can traumatic causes of CN4 palsies generally resolve?
6 months
When may strabismus surgery be indicated for CN4 palsy`(2)?
Congenital or non-resolving CN4 palsies
List 5 causes of CN6 palsies.
Compression
Increased intracranial pressure
Trauma
Ischaemia
Inflammation
What is a symptom of CN6 palsy? What about if its only mild (2)?
Horizontal double vision
-if mild, only present at distance or on side gaze to the side of the lesiond
If you have a case of possible CN6 palsy, when should you suspect tumour causes (10)?
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
What is a sign of CN6 palsy?
Decreased abduction of one eye with slow abducting saccades
List three differential diagnoses for CN6 palsy.
Myasthenia gravis
Restrictive esotropia from a tight medial rectus
-TED
Congenital duanes retraction syndrome
-no double vision
What should you do if there are multiple affected cranial nerves or unexplained double vision?
Urgent referral to a neuro-ophthalmologist
