Duane's & Brown's Syndrome Flashcards
What is an incomitant deviation?
The angle of the deviation changes in different directions of gaze
What are the mechanical characteristics of incomitant deviations
FUG-LEG
- Forced Duction Test reveals limitation
- Up or down shoots
- Globe retraction
- Limitation is opposite the positions
- Equal limitation on duction and version
- Doesn’t have full muscle sequelae
What is the Forced Duction Test?
The eye is moved forcefully with forceps in different gazes, if there is a full movement then it is NOT a mechanical deviation
What are up-shoots or down-shoots?
Occurs due to tight lateral rectus muscle attached to the globe which causes the muscle to slip off the globe when the eye is adducting
How are up-shoots and down-shoots different from up-drift and down-drift?
An up drift is when theres a slow progression upwards but upshoots go horizontal, horiz, vertical )
What is globe retraction?
Eye physically pulled back into the orbit
What does Limitation is opposite the positions mean?
Eg. adduction and abduction
What does equal limitation on duction and version
A duction is an eye movement involving only one eye. A version involves both eyes.
On ocular motility ,one eye and both eyes. have same amount of movement
What does it mean that it Doesn’t have full muscle sequelae ?
Only has over action of cotralateral synergist?
What is Duane’s Retraction Syndrome?
A congenital condition, people are born with it (but may be identified later in life)
It is an abnormal horizontal eye movement in either direction,
Which gender is duane’s more common in
females
Does duane’s affect one eye or both eyes?
Unilateral is most common but can be bilateral and symmetric in 20%
What is a risk factor for duane’s
Family history
What is duane’s caused by?
Neurogenic-relating to nerves
Myogenic-relating to muscle tissues
Which cranial nerve supplies the lateral rectus?
6th
What cranial nerve supplies the medial rectus?
3rd
Describe the neurogenic cause of duane’s
Abnormal innervation of the LR- due to an absent or hypoplastic 6th nerve
What does hypoplastic mean?
Underdeveloped
What happens if the 6th nerve is absent or is underdeveloped ?
If ABSENT= then LR will be supplied by branches of 3rd nerve
If UNDERDEVELOPED= If underdeveloped- then the LR will be supplied by both 3rd and 6th nerve
What problem arises when the 3rd nerve starts to supply the LR?
3rd usually supplies MR but if it is also supplying LR, u get co-contraction (simultaneous contraction of agonist and antag) = limitation of horizontal eye in either direction
Describe. the myogenic cause of duanes
Fibrosis or inelasticity of the LR & MR muscle inserts abnormally
LESS COMMON, people usually go with the neurogenic theory
What are the 4 clinical signs of duane’s syndrome?
- Complete or partial absence of abduction (partial is less common)
- Due to co-contraction there will also be partial loss off adduction (sometimes)
- Deviation in primary position-=Eso/Ex/orthophoria (if problem is mainly abduction eye becomes esotropic and if it’s mainly adduction then exotropic)
-Compensatory head posture (CHP)
Face turn to the affected side in the distance- ESO
Face turn to the unaffected side for near -EXO
If the RE is ESO, why do they turn their face to the right in the distance?
RE is ESO, u will turn your face right cus ur re will go to the left/ in where there’s less of a problem. Also advise that child to sit on the right side of the class
If the RE is EXO, why do they turn their face to the left for near?
IF RE is EXO, problem with adduction so it becomes exo and u want to get your RE away from the left hand side so face turn to unaffected side which is the left
State 6 other clinical signs of Duane’s
- Poor convergence
- A or V pattern
- Reduced/no binocular function- most px can control this condition with CHP but if they can’t then they lose binocular function
- Up/down shoots on adduction (Both MR and LR are firing at the same time causing up/down shoot).
- This induces ptosis - ptosis and retraction will cause narrowing of the palebral fissure on one side and widening the other side
- Narrowing of pal fissure on adduction and widens on abduction/
What tests can help you classify the type of Duane’s syndrome it is?
Occular Motility- Brown’s classification
EMG-Huber’s classification (your never gonna do EMG so stick with brown’s classification)
What is Brown’s classification of Duane’s syndrome?
3 types:
Type A- ABduction > aDduction
Type B- ABduction only limited
Type C- ADduction > aBduction
What is Huber’s classification of Duane’s syndrome?
Type I- max innervation LR in aDduction (Type B)
Type II- co-contraction of MR and LR on aDduction (Type C)
Type III- co-contraction of MR and LR on aDduction & loss of innervation to LR on abduction (Type A)
By looking at a picture how can you classify the type of Duane’s
First work out the eye that is affected and then what is limited. Use sclera as a marker
Look at examples on lecture slides
Which type of Duane’s is the most common?
Type A/type III
Describe Type A
- Abduction is more limited than adduction
- Usually esotropic in primary position
- CHP face turns towards affected side/eye
When the px tries to move their eyes in or out there will be an eye which doesn’t move all the way, check is this worse when trying to move eyes in or out
Describe type B/type I
ABduction only limited
Esotropia in primary position
Face turn to affected side
Describe type C/type II
ADduction more limited > abduction (both limited by adduction more limited)
Exotropia in primary position
CHP face turn to unaffected side
Could have poor convergence
Name 6 Occular associations of Duanes
Ocular- developmental abnormalities:
- Coloboma
- Heterochromia (diff iris colours)
- Lens opacities
- Microphthalmos-lens too small
- Persistant pupillary membrane
- Crocodile tears
What should you do if px has duane’s and they don’t know?
Refer to opthamolgist due to the possibilty of there being these occular associations
Refer to the Doctor for a general physical examination to eliminate the presence of other associated syndromes
Name 6 Systemic Associations-skeletal/facial abnormalites
- Goldenhar’s syndrome (maldevelopment of jaw)
- Klippel-Feil syndrome (fusion of neck bones)
- Abnormal ear formation
- Deafness
- Syndactyly
- Cleft palate
- Thalidomide syndrome
What tests do you do if you suspect duane’s?
Family history
V-A CHP CT OM Measurement (Hess,Field of BSV, PCT)
Refraction
Fundus/media
Optional forced duction testing and/or force generation testing
When suspect duane px is referred to doctor what may they do?
Genetic testing and if theres a genetic link they will ask u to contact other family members within first year of life.
How do you manage Duane’s if px is under 8 yrs old?
- Routine referral to check systemic/ocular associations
- Ensure BSV is maintained
- Treat any amblyopia (As under 8 can decompensate)
- Give specs if needed
- Treat if severe
How do you manage Duane’s if px is over 8 yrs old?
Routine referral if not yet already been referred to check ocular/ systemic associations
- Refer also to treat if severe: improve symptoms, cosmesis (if they have a massive deviation or head posture)
What does the treatment of Duane’s involve?
- Refraction
- Use of CHP
- Occlusion if amblyopic
- Prisms
- Surgery
- Botulinum Toxin
If px has a large deviation or large CHP, how will surgery or prisms help?
Improves cosmesis and symptoms but will not be able to restore normal eye movement/6th nerve
What is Brown’s syndrome?
Can be congenital or acquired abnormality of the superior oblique muscle
Describe the cause of congenital Brown’s syndrome
It’s a mechanical restriction of the SO muscle/ tendon sheath
- Short tendon sheath
- Short tendon
- Inelastic muscle/tendon
- Orbital adhesions
Describe the cause of acquired Brown’s syndrome
A problem with SO itself or the trochlear (cranial nerve 4)
How can the trochlear nerve be damaged?
-Traumatic: car accident, dog bite, sports injury
Iatrogenic: frontal sinus surgery, scleral buckle
Inflammatory: chronic sinusitis, trocheilits, rheumatoid arthritis
Orbital masses
What can cause a problem with the SO?
- Inflammatory
- SO tendon cyst
- Iatrogenic: SO tucking (during surgery for SO palsy
What are the symptoms of Brown’s?
- Sporadic pain/discomfort/diplopia experienced when trying to look up
- CHP (head/chin up) often 1st thing parents notice
- Unable to elevate eye
Why do they put their head up in Brown’s?
Because they can’t look up they put their head up (eyes away from the problem)
Is Brown’s affecting one eye or both?
-90% unilateral
What are the clinical signs of Brown’s?
Limitation of elevation in aDduction
Severe limitation of elevation in aDduction, direct elevation, and aBduction
Down drift of affected eye contralateral version
Over-action contralateral synergist (SR)
- A or V pattern reported
- Forced duction - restricted elevation in adduction
- CHP: chin elevation, head tilt affected side (hypo side), face turn normal side
- Mostly straight primary position (PP) good BSV: rarely hypotropia PP poor/absent BSV
- Palpable click & improvement on re-testing (can resolve)
What is the treatment for congenital Brown’s?
-Often asymptomatic- often no treatment. less problematic as grow older
How do you manage congenital brown’s if they are under 8?
Routine referral to confirm binocularly stable
To monitor (risk of breaking down into tropia)
How do you manage congenital brown’s if they are over 8?
No need to refer if binocularly stable
Routine if symptomatic
How do you manage acquired Brown’s?
-Refer to treat the pathology
What is the treatment for acquired Brown’s?
- Occasionally surgery
- Steroid injection
