Eye Movement Disorders Flashcards
What is an Argyll-Robertson pupil
Classical sign of neurosyphilis Small and irregular pupil Reduced or absent light reflex Preserved accommodation response Usually bilateral
Myotonic pupil
Affected pupil is dilated
Impaired response to light
Constricts very slowly in accommodation with delayed redilatation
Benign condition
May become bilateral
May be associated with absent tendon reflexes (Holmes-Adie syndrome)
Which muscle is innervated by the trochlear nerve
SO4
Superior oblique
Which muscle is innervated the by abducens nerve
LR6
Lateral rectus
How do you examine eye movements in an unconscious patient
Vestibulo-ocular reflex
Response to head movement
Response to instillation of ice-cold water into the external auditory meatus
Useful in distinguishing between brainstem function and death in an unconscious patient
What is monocular diplopia
Diplopia that persists when one eye is covered
Not normally a symptom of neurological disease
Occurs in opthalmological disorders eg. lens opacities
What signs would you expect to find in a third nerve palsy
Ptosis
Eye in a down and out position
Why is there ptosis in a 3rd nerve palsy
Paralysis of the levator palpebrae superioris
Why is the eye in a down and out position in a 3rd nerve palsy
Due to unopposed action of the superior oblique and lateral rectus
What is a surgical 3rd nerve palsy
Fixed and dilated pupil
No reflex response
*Painful
What is a medical 3rd nerve palsy
Pupil sparing
Why is there pupil sparing in a medical 3rd nerve palsy
Parasympathetic pupillary fibres run along the outside of the nerve, so are spared in vascular aetiology
What are some causes of a surgical 3rd nerve palsy
Compression of the nerve:-
Tumour
Posterior communicating aneurysm
Posterior cerebral artery aneurysm
What are some causes of a medical 3rd nerve palsy
Infarction:-
DM
Hypertension
What are the causes of a fourth nerve palsy
Head trauma
More rare:-
Stroke
Tumour
Aneurysm
What signs and symptoms might you expect from a patient with a fourth nerve palsy
Diplopia descending stairs
Head tilt towards the normal side
How would you confirm a 4th nerve palsy
Cover testing
What signs and symptoms would you expect in a patient with a 6th nerve palsy
Unable to abduct the affected eye
Diplopia on looking to the affected side
Horizontal separation of images
What are the causes of a 6th nerve palsy
Damage to the nerve’s blood suppy (vasa nervorum) secondary to diabetes or hypertension
False localizing sign of raised intracranial pressure
What is meant by false localizing sign when referring to a sixth nerve palsy
The abducens nerve has a long and tortuous intracranial course
It is vulnerable to general effects of raised intracranial pressure
Intracranial pressure may be due to a space occupying lesion anywhere in the brain, not necessarily directly compressing the nerve
Which image in diplopia is the false image (from the affected eye)
The outermost image
