Browns syndrome Flashcards
Histology
by Brown in 1950 and it is usually unilateral and there are only 10% bilateral cases and these are occasionally reported in females.
Cong or Acq
It can be congenital or acquired
Frequency
There is an equal frequency in males and females and the RE is more affected than the LE.
Features
Restriction of elevation in adduction
Normal or near normal elevation in abduction
Positive forced duction test
Absence of muscle sequlae except o/a contralateral SR
Further features
- Downdrift on adduction
- Widening of palpebral fissure on adduction
- V pattern (A also reported)
- Improved movement with ‘click’ on repeated testing
- AHP
Youtube summary
https://www.youtube.com/watch?v=jBASYYMhHVA
Grading browns
Mild
Mod
Severe
Mild browns
Position with limited elevation
PP- no
Adduction- no
Elevation in adduction- yes
Moderate browns
Position with limited elevation
PP- no
Adduction- yes
Elevation in adduction- yes
Severe browns has limitated elevation where…
EVERYWHERE
Position with limited elevation
PP- yes
Adduction- yes
Elevation in adduction- yes
Superior oblique anatomy
https://www.youtube.com/watch?v=f_rb6FMVHPk
at 6:43
Aetiology of congenital browns
- Short anterior tendon sheath
- Developmental Anomaly affecting trochlea/superior oblique complex
- Inelastic superior oblique tendon
- Nodule or swelling on the tendon
- LR pulley instability Bhola 2005 (1 case)
- In the CCDD spectrum
CCDD disorders
- CFEOM (congenital fibrosis of extraocular muscles)
- 3rd nerve palsy
- 4th nerve palsy
- 6th nerve palsy
- Moebius syndrome
- Duane syndrome
- Brown syndrome
- Ocular synkinesis syndromes
- Horizontal gaze palsy with progressive scoliosis.
Is Browns a CCDD
It is linked with a congenital SO palsy and there is a proposed mechanism for Browns and Congenital SO palsy
Aetiology in acquired browns
- S.O. tuck
- Injury to trochlea area (less since seat belt law introduced)
- Orbital trauma
- Inflammatory (Elnahry AG, Elnahry GA, 2019)
- Rheumatoid arthritis
- Surgery for blow-out fractures (Ji et al, 2015)
- Comestic blepharoplasty (Wilde et al, 2012)
- Orbital mass (Fard et al, 2011)
- Infection (COVID19, Haliyur et al, 2022; Kızıltunc et al, 2021)
VA and AHP in acquired browns
VA
Usually normal unless associated manifest deviation
AHP
Chin elevation, tilt to affected side and turn to unaffected side
Further investiagtion of browns
usually binocular in pp
CT
Often binocular in p.p. possible hypophoria/exophoria
May have reduced control become manifest without AHP
Binocular Function
Usually good binocular functions
Test for potential BSV if manifest
Plot field of BSV in older child or adult
Measurement
PCT in p.p.
May measure on versions and elevation
Plot Hess chart (dog ear appearance of affected eye) in older child
Differential diagnosis of Browns
IO palsy- muscle sequelae present, A pattern, negative FDT
Double elevator palsy- Elevation limited in all elevated positions , no alphabet pattern, FDT may be negative dependant on aetiology
Management
Observe- 75% show spontaneous improvement (Dawson et al 2009)
Surgery: Indicated if decompensating, mkd AHP or poor cosmesis, Results often disappointing
Surgical options
SO tendon spacer (expands muscle)
Tenotomy
Recession of contralateral SR
Tenotomy
Tenotomy with preservation of intermuscular connective tissue septum
Tenotomy with removal of intermuscular connective tissue septum.
Recession of contralateral SR
Reverse S.O. tuck. Operate on horizontal muscles if large horizontal angle. Tendon Splitting Moghadam (2014) Dubinsky-Pertzov et al(2021)
Trochlea reconstruction in acquired Brown’s
Steroid injection used to
To reduce inflammatory reaction or prevent fibrosis in trauma
Some success in early onset (Trimble 1988) though not sustained
Exaggerated traction test
when done and repeated
Squirrell et al case report in congenital Brown’s.
Performed under GA & steroid injection given following traction test.
Repeated 5months later
Summary
- Restriction of elevation in adduction
- No development of muscle sequelae
- Often improve / resolve
- Surgery only if symptomatic
- To do: Read Ansons / Davis 2014 ed: p 545-51
