Brown's syndrome Flashcards
what is brown’s syndrome
Ocular motility defect
Limitation of the affected eye on elevation in adduction
Both actively and passively
describe what you will see in a muscle sequelae of a px with brown’s syndrome
- greatest limitation is in up gaze and in adduction
- in pp = px has downward and outward deviation of that eye
- mechanical so only O/A of contralateral SR, inferior field full (i.e. second stage muscle (sequelae)
what will the affected eye look like in pp in brown’s syndrome
downward and outward deviation of that eye
is brown’s syndrome unilateral or bilateral, and by how much of cases
90% unilateral
what 2 cases are equal in brown’s syndrome
RE = LE
Female = male
what does congenital and acquired brown’s syndrome have the same of
the same ocular motility defect
what do most patients with brown’s syndrome have
most have binocular single vision
what varies from one patient to the other with brown’s
Degree of limitation
some patients will gain a AHP to see BSV
the AHP will vary depending on the extent of their OM deficit
what are the 4 possible congenital aetiologies of brown’s
first mention the most commonly accepted theory
then mention the 3 other less commonly accepted theories
Most commonly accepted theory:
- Inelastic or short Superior Oblique tendon
Less commonly accepted theories:
- Nodule or swelling of the tendon
SO muscle and tendon are unable to relax to allow the eye to elevate = limitation of that eye
Unlikely to improve over time (stationary variety)
- Thickened trabeculae
SO tendon and trochlear connected during embryological development by thickened trabeculae which persists rather than remodels and so inhibits passage of tendon through the trochlear
More plausible it will spontaneously resolve - Thickened vascular sheath
Vascular sheath enveloping SO tendon may be thickened thus reducing smooth passage of tendon through the trochlear
Intermittent variety – idiopathic click
what is the acquired aetiologies of brown’s all based on and give 3 possible aetiologies
Secondary changes in previously normal Superior Oblique tendon or tendon-trochlear complex
- Iatrogenic
Following surgery to strengthen SO (tuck) for SO/4th CN palsy - Inflammatory
Rheumatoid arthritis, causes swelling on the tendon
Stenosing tenosynovitis “trigger thumb” analogy - Trauma
Road traffic accidents, ENT surgery, direct trauma e.g. “canine tooth” syndrome from dog bites
give 3 reasons why you will want to investigate someone with brown’s syndrome
- Diagnose
- Binocular vision potential
- Plan management
Cosmetic vs functional outcome
If the BSV that they do have is controlled very well with an AHP and also want to know how big that AHP is e.g. if its a marked chin posture = will need some form of surgery to try and reduce that underlying deviation down for them so its easier for them to control
what 3 things may be included in the ‘signs’ of your case history of someone with brown’s syndrome
- Abnormal eye movements: a vertical deviation of the unaffected eye (hypert) affected eye not able to look up
- Strabismus: will notice a squint in pp, but usually when they try to look up, will notice elevation on the other eye
- Abnormal head posture
what types of symptoms may a patient with brown’s syndrome complain of
Usually symptom free
Pain / discomfort of affected eye on elevation in adduction
- Tugging around trochlear area - Vertical diplopia
wich type of aetiology of brown’s will cause Pain / discomfort of affected eye on elevation in adduction and why is this
Experienced when they have a nodule of the SO tendon
This causes pain, or a flicking sensation when the eye tries to elevate
Because the nerve tries to go through the nodule itself
what 5 tests should be included in your orthoptic report for someone with brown’s syndrome
Abnormal head posture for BSV in moderate / marked case
Vision
Cover test (with and without AHP)
Prism assessment if diplopia in primary position
Ocular motility
what will be the AHP for someone with brown’s syndrome and what does it vary with
Chin elevation
Head tilt to affected side
Face turn to unaffected side
varies with the degree of OM deficit the px has
when getting a case history from the parent, what will they report of noticing with their child who had brown’s syndrome
usually notice a vertical deviation of the affected eye and will notice the unaffected eye has drifted up
how will you carry out your vision test on a patient with brown’s syndrome
what will you find majority of the time
what may you find if the child has a constant manifest squint
- cyclo refraction
- majority have equal vision (as they adopt a AHP)
- amblyopia if constant manifest squint (where they will need relevant patching treatment)
how will you carry out a cover test on a patient with brown’s syndrome and why
what results will you find with majority of patients in pp
where will you find these patients to have BSV and what 2 tests will you carry out in this position
- with and without AHP
with: to make sure/check that everything is absolutely fine and to make sure that they are controlling to a latent deviation
the moment you put their head straight i.e. without the AHP, they are likely to have a manifest deviation - Majority are phoric (hypo) in primary position
- BSV in lower field
Prism fusion range
Stereoacuity
when will you find that you need to do a prism assessment if diplopia in primary position and what will you find and what can you do to correct this in clinic
- found usually in slightly older children ~ 6-7 y/o, who haven’t been diagnosed formally of having brown’s syndrome
- when looking up into elevation with their head straight, px will have diplopia
- in clinic, can alleviate that diplopia with some fresnel prisms
describe what you will see with the affected eye when doing OM on a patient who has brown's syndrome in: elevation in adduction direct elevation elevation in abduction adduction abduction
and 2 other additional observations
elevation in adduction: limitation of eye (is greatest here)
direct elevation: slight limitation
elevation in abduction: full or very slight limitation
adduction: downdrift (this is the side of the gaze of the affected eye)
abduction: normal
will also see:
V pattern on divergence of eyes in elevation
- Abducting action of Inferior Oblique muscles as elevation attempted
Discomfort/pain/click on attempted elevation in adduction
- May show an improvement on repeated testing
how will you differentiate brown’s syndrome from a IO palsy
the muscle sequelae of brown’s syndrome will only be limited to the overaction of contralateral Superior Rectus as mechanical
where as IO palsy muscle sequelae will be full as its neurogenic
why will you see a V pattern on divergent of eye in elevation in someone with brown’s syndrome
as abducting action of Inferior Oblique muscles as elevation is attempted
list 2 ddx of browns syndrome
- Isolated Inferior Oblique Palsy
- Blow-out fracture
how can you differentiate browns syndrome from an isolated inferior oblique palsy
Because its RARE!!!! Suspect Browns until proven otherwise
Neurogenic would have full muscle sequalae
Overaction contralateral SR, Overaction ipsilateral IO, underaction Contralateral IR
how can you differentiate browns syndrome from a blow out fracture
- Clear history of trauma
- Limitation in elevation, greatest in abduction
- Retraction of globe of up gaze
- Infraorbital nerve anaesthesia
why is a conservative treatment mostly chosen to manage someone with browns syndrome
give 3 reasons
- Majority symptom free BSV in PP and lower field
- Slight head posture depending on degree of limitation (nothing needs to be done, something only done is AHP is marked)
- Natural history:
Limitation may improve over time, if not up-gaze used less as child grows in height therefore anomaly less noticeable
what is the non-surgical management for someone with browns syndrome
give 2 reasons why
what is a disadvantage
when is this method only indicted
- Retrobulbar steroid injection
- Reduces inflammation
- Prevent development of fibrous tissue following trauma
- Not substained effect in all cases
- Indication only in patients who would otherwise of had surgery
But as this treatment is down under local anaesthetic, the px cannot be too young
give 3 reasons when surgical management for browns syndrome is indicated
- Marked AHP / significant angle in primary position
- Cosmetic problem
- Indication of decompensation of squint (i.e. deviation is significantly reduced with AHP but px cannot control it for too long)
list the 4 surgical options
- Weaken Superior Oblique tendon (tenotomy)
- Superior Oblique tendon expander (lengthening procedure)
- Weaken (recess) contralateral Superior Rectus
- Horizontal muscle surgery (not done if have vertical squint)
what can the surgery outcome for browns syndrome be
unpredictable as…
results range from no change in limitation in elevation in adduction to a complete SO palsy
what is the only aim for surgery in browns syndrome and what must you tell the parent before hand
- surgery is only for the poor cosmetic reasons in pp or to reduce the angle of deviation to control it more easily
- must tell parent that limitation of eye movement will still persist
if the parent is mostly noticing the eso and exo deviation in pp and not the hypert/hypot dev in pp, what surgery can you do
either weakening or strengthening treatment of the horizontal muscles only
but only to counteract the horizontal deviation
if the parent is mostly noticing the vertical squint, what surgery can you do
surgery on the SO of affected eye or SR of unaffected eye
