Browns Syndrome Flashcards
What did Brown (1950) first find out about with regards to Browns Syndrome?
8 cases restricted elevation in adduction finding that during surgery shortened tendon sheath of superior oblique muscle tendon was found and thus used to be called Superior Oblique Tendon Sheath Syndrome (SOTSS)
The abnormality in most cases involves the superior oblique tendon and/or the trochlear complex.
What is the prevalence rate of Brown’s Syndrome?
Rare - 0.22% of all strabismus up to 10% of cases in vertical strabismus
Who/what does Brown’s Syndrome affect the most?
- Usually unilateral (<10% bilateral)
- RE more commonly affected
- 59% females affected
- Can be congenital or acquired
What is Browns Syndrome?
Superior Oblique + Mechanical Restriction = Restriction of Elevation in Adduction
Tight muscles, limits movement in position of gaze opposite (May be referred to as direct leash)
What do OMs look like between ductions and versions in Browns?
OMs: ductions the same as versions
Retractions may be seen but saccades are normal
What does a Hess Chart look like in Browns?
Hess chart: “squashed” inner and outer fields in area of greatest limitation
What is IOP like in Brown’s Syndrome?
Increases when looking away from limitation
What does the muscle sequelae look like in Brown’s Syndrome?
Only one step (overaction of contralateral synergist)
What does a forced duction test look like in Brown’s Syndrome?
Positive FDT (normally performed before surgery)
What is the purpose of a FDT in Brown’s investigation?
- To differentiate a mechanical from of a non-mechanical cause for the limitation on elevation and differentiates Brown’s syndrome from IO palsy
- To differentiate Brown’s from a tight IR muscle – retropulsion (pushing the globe into the orbit) increases the FDT in Brown’s Syndrome but decreases it if contracture of the IR is present
What is the congenital aetiology of Browns?
Tendon
- Nodule/swelling
- Tight/inelastic
- Short (anterior sheath)
- Congenital fibrosis
Pulley System
- Tight
- Misaligned
Innervation
- Anomalous to SO and IO muscles
- Bifid (muscle split in 2 with another insertion site) sclera insertion of SO
What is Brown’s Syndrome a category of? Disorder-wise
CCDD (Congenital Cranial Dysinnervation Disorder)
What is the systemic aetiology in acquired Browns?
- Dysthyroid disease
- Arthritis
- Lupus
- Sinusitis
- Sjogren Syndrome
What is the ophthalmic aetiology in acquired Browns?
- Blepharoplasty (eyelid lift, is a surgical procedure that removes excess skin and fat from the upper or lower eyelids)
- Glaucoma implant / any implant in superior nasal region
- Orbital floor fracture
- Iatrogenic (following surgery: superior oblique tuck)
- Trochleitis (inflammation of trochlea within the tendon sheath)
- Neoplasms of superior nasal orbit (tumour)
- Trauma
What are some acquired Browns aetiology that aren’t systemic or ophthalmic?
- Cyclic
- Idiopathic
- Inflammation
- Postpartum
- Infection
- Age related degeneration
- Iatrogenic following frontal sinus surgery
What are some features of Browns Syndrome?
- Limitation of elevation in adduction. If restriction of movement is severe, there may also be some limitation of direct elevation and even of elevation in abduction.
- Down-drift of the affected eye on contralateral version, sometimes accompanied by widening of the palpebral fissure.
- o/a of contralateral SR. Other muscle sequelae doesn’t normally develop so there’s no o/a of SO on affected side but o/a of IO on unaffected side is sometimes reported.
- A or V patterns
- Typical Hess chart shows limitation of elevation or no or minimal abnormality in the lower field
Discomfort on attempting elevation in adduction - Improvement in elevation in adduction when repeating testing in that direction. Can get ‘click syndrome’ where you hear a click sound, in some cases this is followed by o/a of ipsilateral IO with restricted movement in downgaze. The ‘click’ can indicate the condition may spontaneously resolve.
- Torsion in upgaze
- Positive FDT
- AHP – head up, head tilt to affected side and head turn to contralateral side. Head up only if syndrome is bilateral and symmetrical. Often Brown’s patients can maintain BSV without AHP.
What does Browns look like in elevation?
Limited elevation in adduction. If restriction of movement is severe, there may also be some limitation of direct elevation and even of elevation in abduction.
What happens in contralateral version in Browns Syndrome?
Down-drift of the affected eye on contralateral version, sometimes accompanied by widening of the palpebral fissure.
What does the muscle sequelae look like in Browns Syndrome?
o/a of contralateral SR. Other muscle sequelae doesn’t normally develop so there’s no o/a of SO on affected side but o/a of IO on unaffected side is sometimes reported
What does a Hess Chart look like in Browns Syndrome?
Typical Hess chart shows limitation of elevation or no or minimal abnormality in the lower field