Download acute monocular blindness & basic neuro ophthalmology

Almero Oosthuizen
UCT/US Emergency Medicine
January 2009
PERSPECTIVE:
Why is this important?
• SMALL problems with the eye causes BIG
problems for the patient
• EYE problems may be markers for serious
SYSTEM problems
OUTLINE
• Basic Neuro Ophthalmology
– Visual, reflex and gaze pathways
– Some clinical findings
• Overview of sudden visual loss
• Acute monocular blindness
– Overview and some conditions
• Summary
BASIC VISUAL PATHWAYS
PUPILLARY REFLEXES
1. Reaction to light (direct and consensual)
2. Reaction to accommodation
3. Autonomic reflexes
PUPIL MUSCLE ACTIONS
LIGHT REFLEX PATHWAYS
LIGHT REFLEX PATHWAYS
LIGHT REFLEX PATHWAYS
AFFERENT PUPILLARY DEFECT
• Total loss of the AFFERENT reflex pathway
– Blind eye, i.e. severe retinal damage or optic nerve
pathology
• For a LEFT APD
– Light into left eye: no direct light reflex (L)
– Light into left eye: no consensual reflex (R)
– Light into right eye: normal direct and consensual
reflex
RELATIVE AFFERENT PUPILLARY
DEFECT
• Incomplete damage to AFFERENT pathway
– Partial retina or optic nerve damage
• For LEFT RAPD
– Light into left eye: left and right pupil constrict
– Light into right eye: both pupils constrict further
– Back to left eye: both pupils dilate, but not
completely
– Light away: both pupils dilate completely
SOME OTHER PUPIL DEFECTS
ACCOMODATION VS. LIGHT
• Accommodation pathway: visual cortex to
CNIII nucleus
• Absent light, Intact accommodation
– Midbrain lesion (i.e., Argyll Robertson, syphilis)
– Cilliary ganglion lesion (i.e. Adie’s pupil)
• Failure of accommodation alone
– Midbrain lesion (occasional)
– Cortical blindness
CONJUGATE GAZE PATHWAYS
INTERNUCLEAR OPHTHALMOPLEGIA
• Caused by a brainstem lesion involving the
MLF
• Common in Multiple Sclerosis
• Sometimes with small brainstem infarcts
INTERNUCLEAR OPHTHALMOPLEGIA
• Right INO
– Lesion of right MLF
– On attempted left lateral gaze:
• Right eye fails to ADduct
• Left eye develops coarse nystagmus in ABduction
• The side of the lesion = the side of the failed
ADduction, NOT the side of the (more
obvious) nystagmus
INTERNUCLEAR OPHTHALMOPLEGIA
BLINDNESS: OUTLINE
• Basics of blindness
• Clinical approach
• Monocular blindness
BLINDNESS: BASICS
• Decrease in visual function with varying
degrees of
– Loss of visual acuity
– Visual field defects
– Abnormalities of visual information processing
• Multiple etiologies, basically divided:
– Eye problems
– Neuro-ophthalmological problems
– Functional visual loss
ETIOLOGY
• Three groups
– Eye, neuro-ophthalmological, functional
• Primary diseases of the eye
– I.e. glaucoma
• Systemic diseases INVOLVING the eye
– I.e.: hypertension, diabetes, infections
• Systemic diseases AFFECTING the eye
– I.e.: thromboembolic events (RAO)
REMEMBER THE ANATOMY!
TIMEFRAME AND PAIN
• Transient (<24hr)
• Persistent (>24 hr)
– Sudden, painless
– Gradual, painless
– Painful
• Monocular: anterior to chiasm
• Binocular: posterior to chiasm
TRANSIENT (<24 HR)
• Seconds
– Papilledema
• Minutes
– TIA (amarausus fujax) - unilateral
– Vertebrobasilar artery insufficiency – bilateral
• Minutes to an hour
– Migraine
– Sudden BP changes
PERSISTENT (>24 hr)
• Sudden, Painless
– Retinal artery or vein occlusion
– Vitreous bleed
– Retinal detachment
– Optic neuritis/neuropathy
– Temporal arteritis
PERSISTANT (>24 hr)
• Gradual and painless
–
–
–
–
–
–
–
–
–
Cataract
Age
Refraction
Open-angle glaucoma
Chronic retinal disease
Macular degeneration
Diabetic retinopathy
CMV retinopathy
SOL
PERSISTANT (>24 hr)
• Painful
– Corneal abrasion or ulcer
– Angle closure glaucoma
– Optic neuritis
– Iritis/uveitis
– Keratoconus with hydrops
• So, mainly EYE problems
NEURO-OPHTHALMOLOGICAL
• Visual loss not readily explained my an
abnormality on physical examination
• Pre-Chiasmal (often monocular)
– Optic neuritis
– Ischemic optic neuritis
– Compressive optic neuritis
– Toxic and metabolic optic neuritis
NEURO-OPHTHALMOLOGICAL
• Chiasmal
– Chiasmal compression from pituitary or other IC
tumours
– Classically bitemporal hemianopia
– SOL’s may compress asymmetrically!
• Post-Chiasmal
–
–
–
–
CVA
Tumour
AV malformation
Migraine
CLINICAL APPROACH
• Rapid assessment to find and treat reversible
conditions
• Remember to consider systemic implications
• As always:
– History
– Physical
• VA, pupils, fundoscopy, inspection of the globe
(fluoresscine!)
• Use an anatomical system
– Tests
ACUTE MONOCULAR BLINDNESS
• Always an emergency
• Neuro-ophthalmological (see before)
– Problems BEHIND the eye
– Pre-chiasmal group (mainly optic
neuritis/neuropathy)
• Non neuro-ophthalmological
– Problems WITH the eye
NON NEURO-OPHTHALMOLOGICAL
•
•
•
•
•
•
Central retinal artery occlusion
Central retinal vein occlusion
Temporal arteritis
Retinal breaks and detachment
Vitreous bleed
Retinal/macular disease
– incl retinal vasculitis, CMV etc
•
•
•
•
•
Corneal disease (trauma, ulcers etc)
Glaucoma
Iritis/uveitis (incl ant chamber bleed)
Lens detachment
Many other, more obscure causes
CENTRAL RETINAL ARTERY OCCLUSION
General
• Abrupt, painless, usually unilateral blindness
• Usually some degree of permanent loss if not
corrected immediately
• ICA -> ophthalmic artery -> retinal artery
• Occasional additional supply by the
cilioretinal art.
CENTRAL RETINAL ARTERY OCCLUSION
Etiology
• Same as for any thromboembolic disease
– ICA atherosclerosis (all the usual CVA risk f’s)
– Cardiac emboli (AF, SIBE etc)
• Other (often systemic) problems
– Haematological disease (i.e. sickle)
– Hypercoagulable states
– Autoimmune/inflammatory states (i.e. lupus, GCA)
CENTRAL RETINAL ARTERY OCCLUSION
Clinical
•
•
•
•
•
Blindness: sudden, dramatic, painless
Often only a small unaffected area
May be transient or ‘stuttering’
TAPD or RAPD
Fundus
– Pale, edematous retina, may see embolis
– Macula: cherry red spot (underlying choroid)
– May see cholesterol plaques etc
CENTRAL RETINAL ARTERY OCCLUSION
Fundus
CENTRAL RETINAL ARTERY OCCLUSION
Treatment
• Not much helps. Almost everyone does badly
• Act fast!
– >240min: irreversible damage ;<100 min: best chance of benefit
• Ocular massage
– Press for 15s on closed lid, release suddenly, repeat for 15 min
• Decrease IO pressure
– Ant chamber paracentesis (ophthalmologist), IV diuretics,
trabeculectomy
• Other strategies (insufficient evidence, ophthalmologist
decides)
– Lytics (risk:benefit), vasodilators etc.
• OPHTHALMOLOGIST EARLY
CENTRAL RETINAL VEIN OCCLUSION
General
• BRVO vs. CRVO
• Ischemic vs. Non-Ischemic
• Caused by
– Crossing of art/ven, with ven compression and
stasis/thrombosis
– Thrombosis in the main draining retinal vain
• Results in
– Disk/retinal edema, hemorrhage, vascular leakage
• Complications
– Neovascularisation and glaucoma
CENTRAL RETINAL VEIN OCCLUSION
Clinical
• BRVO
– Milder symptoms, often noticed on routine exams
• CRVO
– Sudden, unilateral visual loss. Painless. Often
dramatic, often more central
– Classically noticed upon waking in the morning
– Variable TAPD/RAPD
• Fundus
– Disc edema, bleeds, cotton-wool spots, tortuous veins
– ‘Blood and thunder’!
CENTRAL RETINAL VEIN OCCLUSION
Fundus
CENTRAL RETINAL VEIN OCCLUSION
Treatment
• Not much works, and basically nothing in the
acute setting
• Find systemic problems
• Refer to an ophthalmologist
• They may try many therapies
– As for CRAO, plus hemodilution, laser
photocoagulation, steroids
OPTIC NEURITIS
General
• Focal inflammatory demyelination of the optic
nerve (bulbar vs. retro bulbar)
• Causes acute, painful monocular blindness
• Most common in 20y – 40y age group, female
preponderance
• Approx. 30% will go on to develop MS
• 31% will have recurrence of optic neuritis within
10 years
• Consultation with ophthalmology and neurology
is advisable
OPTIC NEURITIS
Clinical
• Acute visual disturbance
– Hours to days
– Often initial loss of colour discrimination and contrast
– Loss mostly central
• Monocular and painful
– Typically pain on moving the eye
• Always some degree of APD
• Natural History
– Worst in about one week, then gradually better over
several weeks
OPTIC NEURITIS
Fundus
•May be normal in
up to 66% (retro
bulbar)
•Rest may have:
1. Optic disk
swelling
2. Blurring of disk
margins
3. Swollen retinal
veins
OPTIC NEURITIS
More pictures
OPTIC NEURITIS
Treatment
• Controversial
• Steroids
– Hastens visual recovery, and may delay onset of
MS, but no benefit beyond 2y compared to
placebo
• So talk to ophthalmology, and discuss with
neurology re work-up for MS
– May offer gadolinium enhanced MRI
• Talk to patients regarding risk for MS
OTHER OPTIC NERVE PROBLEMS
• Please see enclosed information pack
• Examples include
– Ischemic optic neuropathy (i.e. with Temp Art)
– Nonarteritic ischemic optic neuropathy
– Compressive optic neuropathy
– Toxic and metabolic optic neuropathy
• Methanol, chloramphenicol, INH, antifreeze,
ethambutol, thiamine deficiency, pernicious anaemia
TEMPORAL ARTERITIS
General
• Medium- and large-vessel vasculitis
– Extra cranial branches of the carotid artery
• Very rare below 50y, peak 70 – 80y
– 2:1 female to male
• Etiology
– Poorly understood, possibly an infective trigger
• Pathophysiology
– CD4 cell mediated granulomatous inflammation with giant
cells
– Reactive intimal proliferation with occlusion of the lumen
(not thrombosis)
– This causes an ischemic optic neuropathy
TEMPORAL ARTERITIS
Clinical
• Most common features:
– Headache
– Constitutional symptoms (cytokines)
– Tender, hardened temporal/occipital arteries
• Other features
– Tongue/jaw claudication, neuropathies etc
• Visual features
– Visual loss or disturbance, often preceded by
amarousis fujax, may experience diplopia etc.
– Usually painless and monocular, but may be bilateral
TEMPORAL ARTERITIS
Diagnosis
• Clinical picture + raised inflammatory markers
• KEY = Temporal artery biopsy
– Giant cell granulomatous inflammation
• Visual findings
– Visual loss, APD
– Disk pallor and edema, scattered cotton wool
patches, retinal bleeds
TEMPORAL ARTERITIS
TEMPORAL ARTERITIS
Management 1
• Steroids (don’t wait for biopsy)
• If any visual disturbance
– Ophthalmological emergency – try to save the
other eye!
– Many regimes, but initial high dose IV steroids,
followed by a year or more of tapering steroids,
protects vision
– Monitor treatment with CRP and symptoms. If
either worsens, don’t taper further
TEMPORAL ARTERITIS
Management 1
• Example regime:
– 3 days IV Methylprednisolone
– 2 years of oral prednisolone (start at 40 -60mg)
• Temporal arteritis with visual loss should be
referred to ophthalmologists
• Also remember to look for joint involvement
that may indicate polymyalgia rheumatica
SUMMARY
• SMALL problems with the eye causes BIG
problems for the patient
• EYE problems may be markers for serious
SYSTEM problems
• Acute monocular visual loss is an emergency
and should be assessed rapidly
• Involve ophthalmology early
Bibliography
• 5 Minute emergency medicine consult, Rosen and Barkin
• Textbook of emergency medicine, Rosen and Barkin
• Acute monocular visual loss, M. Vortmann et al, Emerg
Med Clin N Am 26(2008) 73-96
• Clinical Examination, 3rd edition; Talley& O’Connor;
Blackwell Science
• MaCleod’s Clinical examination; Munro ed; Churchill
Livingstone
• Principles of Anatomy and Physiology, 11th edition;
G.Tortora, B.derrickson; Wiley press
• Atlas of Human anatomy; Frank H. Netter; Ciba publishing